Science topic

# Particle Physics - Science topic

Explore the latest questions and answers in Particle Physics, and find Particle Physics experts.
Questions related to Particle Physics
• asked a question related to Particle Physics
Question
In a hypothetical situation where I have two wires, ones cross section is a cylinder, and the others a star. Both have the same cross section area, both have the same length. What are the differences in electrical properties ?
Are there any experiments done looking into this ?
Also what would happen if a wire had a conical shape, by length ?
The electrical properties are frequency dependent and are dependent on the electromagnetic field profile around the wire. For example, in a high frequency situation, the electric current will travel close to the surface of the wire. Consider a coaxial cable: if the center conductor is round (circular) and the shield is circular and collinear, the electric field will be evenly distributed around the center conductor and the current (tangential magnetic field) will also be evenly distributed. Hence, the resistance per unit length of the wire will be 1/(2*pi*a*delta*sigma), where a=radius of wire, delta=skin depth, sigma=wire material conductivity.
Now, suppose we have a "star" shaped wire. The electric field (and longitudinal current) will be concentrated at the points of the star. The effective area of the current flow will be reduced in this case and the wire will have a higher resistance than the smooth round wire.
If you have access too electromagnetic field simulator software, why not try some numerical experiments?
• asked a question related to Particle Physics
Question
The energy of β-electrons resp. positrons reaches very high values in many cases. If one follows the theoretical assumption that electron/positron and the β-neutrino share the constant β-decay energy, one comes to the conclusion that a certain part of the neutrinos has negative energy.
The existence of particles with negative energy would have not only theoretical but also real consequences for particle physics.
According to modern calculations, negative energy does not work (see the answers of Stam Nicolis). However, some mystical feeling of the upcoming discovery does not leave me ...
• asked a question related to Particle Physics
Question
A rigid body with vertical proper length J rises along the Y direction in an inertial frame S(T,X,Y) with constant proper acceleration, therefore me may write the equation of hyperbolic motion of the body along the Y direction as:
1) J2 = Y2 - c2 T2
Using Born´s definition of rigidity, the proper length “J” must be invariant under Lorentz transformations between instant commoving inertial frames where the proper length (squared) J2 coincides with the line element (squared) along the Y direction: Y2 - c2 T2. It is straightforward to see that this is the case just for boosts along the Y direction. If the velocity of the body and its inertial commoving frames have an aditional constant component along the X direction, the line element is different, the vertical length J cannot be invariant in the inertial comoving frames and we get a violation of Born´s rigidity.
And it is a pitty that the students fail to take into account simultaneity of relativity since it is a straighforward consequence of the two more basic priciples of SRT:
1) Constancy of speed of light.
2) Equivalence of inertial frames.
• asked a question related to Particle Physics
Question
Consider two particles A and B in translation with uniformly accelerated vertical motion in a frame S (X,Y,T) such that the segment AB with length L remains always parallel to the horizontal axis X (XA = 0, XB = L). If we assume that the acceleration vector (0, E) is constant and we take the height of both particles to be defined by the expressions YA = YB = 0.5 ET2, we have that the vertical distance between A and B in S is always (see fig. in PR - 2.pdf):
1) YB - YA = 0
If S moves with constant velocity (v, 0) with respect to another reference s(x,y,t) whose origin coincides with the origin of S at t = T = 0, inserting the Lorentz transformation for A (Y = y, T = g(t - vxA/c2), xA = vt) into YA= 0.5 ET2 and the Lorentz transformation for B (Y = y, T = g(t - vxB/c2), xB = vt + L/g) into YB= 0.5 ET2 we get that the vertical distance between A and B in s(x,y,t) is:
2) yB - yA = 0.5 E (L2v2/c4- 2Lvt/c2g)
which shows us that, at each instant of time "t" the distance yB - yA is different despite being always constant in S (eq.1). As we know that the classical definition of translational motion of two particles is only possible if the distance between them remains constant, we conclude that in s the two particles cannot be in translational motion despite being in translational motion in S.
Larissa, I might be wrong but I believe that you wanted to post in another quest on dark matter and dark energy.
• asked a question related to Particle Physics
Question
1960 Gell-Mann detected the 3 quarks (up, down & strange) as crossing points of the Kaons and Pions connections in 3 D. The QM only kept the quarks 2 D (spin & charge) without the construction but only the Lagrangian formula for everything. Is that the exact maximum & end of the particle physics ? The way would be clearly "from the SM to the Higgs field with the 61 - 64 Elementary particles with the Data of each particle (of the real matter) .
The gray matter may come later, but first the real matter with 3.15° K.
In addition to all interesting answers, there is a popularization of a science article on a Russian website:
Pages of History: Quarks - half a century (2014) No. 155 / pp. 10 by Alexey Levin
I think the "Eightfold Path", "finally, quarks!", and "from disbelief to acceptance", these 3 sections give some thoughts on your interesting question.
Best wishes.
• asked a question related to Particle Physics
Question
The classical electron radius is well known and effectively represents the charge radius which is 2.82 X 10^-15 m.
The "physical" radius of the free electron has yet to be determined experimentally but is known to be less than 10^-18 m.
Has any body got a more accurate experimental value for the electron radius
Or has anyone got a handle on the theoretical free electron radius,
From the orbital model of the structure of elementary particles, the electron is structured by the orbital of an integer negative electric charge, orbital whose size is of 2.82 Fm. However, it is often believed that the electron is punctual. This is due to the fact that in high energy collision experiments its structure is not detected, being very light (only 0.51 MeV) in front of the collision energy and so its point-like appearance come from its structural electric charge which is punctual (less than 0.001 Fm).
• asked a question related to Particle Physics
Question
Hello everyone,
As you've probably guessed I'm fairly new to Geant4 and I am working on a project where I have to determine energy deposits in various organs after Irradiating the thyroid with I(131).
For starter I want to use the available human phantom just to get the gist of it but my problem is how should I simulate the radiation, provided that Iodine is concentrated in the thyroid and that it has a half life of 8 days, said Iodine disintegrate by emitting an electron and a gamma ray.
My questions are many:
1/Should I take the thyroid as the point from where the radiation is being emitted?
2/How will the half life be taken into account?
3/Do the organs provided in the example have sensitive detectors or should I create them?
4/How does the scoring goes?
All in all I would appreciate any and all help and if anyone has a clear idea of how I should proceed please your help is most welcome.
Thank you.
Hello,
Thank you Hadi Jabbar Alagealy & Keyvan Tabaei for responding to my question.
I will try to explain myself better so you would get a clear idea of what I am trying to achieve.
I have sent you a message and I would be very glad if you responded.
• asked a question related to Particle Physics
Question
An electron’s electric-magnetic field extends far from the electron’s center of charge. When we designate the electron’s energy, we include the energy in the electron’s electric field. The energy in an electric field external to charge e is: Eext = αħc/2r , where r is radial distance and α is the fine structure constant. For example, the energy in the electric field beyond 1 nanometer from charge e is about 1 eV. NIST specifies an electron’s energy to a standard uncertainty of 1.5x10-4 eV. Therefore, the experimentally measured electron energy includes the electron’s electric field energy extending out to about 5 micrometers. We know an electron’s electric field extends far beyond this distance. Does this mean an electron’s radius also extends indefinitely?
How do you visualize the structure of an electron? Do you include an electron’s electric field as a fundamental part of an electron? If so, how big is your electron model?
Andre,
You are attempting to explain the speed of light using the properties of E and B fields. It is true that these fields are important, but a complete answer must go deeper and answer the question: What is the structure of all fields? If the quantum vacuum is modeled as a sea of Planck length vacuum fluctuations, oscillating at Planck frequency (Wheeler’s “quantum foam”), then the quantum vacuum becomes a quantifiable field. Planck length (Lp) times Planck frequency (ωp) equals the speed of light (Lpωc = c). The quantum vacuum becomes a stiff elastic medium with an enormous impedance and bulk modulus. Waves in this medium propagate at the speed of light. This is proposed to be the single “universal field” that generates all particles, all forces and all other fields.
Support for this statement comes from the fact that this model generates predictions that the gravitational and electrostatic forces between two electrons are related through a square exponent. This falsifiable prediction is proven correct by 8 equations in Section 12 of the attached preprint. This paper also proposes an answer to the question: Is an electron’s electric field part of the electron’s structure? A wave-based electron structure is proposed and tested. This wave-based electron model extends indefinitely. It creates both an electron’s electric and gravitational fields. The energy in an electron’s electric field is a fundamental part of the electron model.
• asked a question related to Particle Physics
Question
But 1960 Gell-Mann constructed a kind of stereo model with Baryon Decuplet, choosing Spin-Strangeness-Charge. Why couldn't we do it even not with the most technical programs? Should particle physics be forever an obscure knowledge for Mathematic secret bees
we have nothing at all as the new cern-results show-
• asked a question related to Particle Physics
Question
Recently, I've been selected for an ICTP program named Physics of Complex Systems. But, I have a keen interest in Particle Physics & Quantum networks. As statistical mechanics involved in Complex systems. One of my professors said that statistical mechanics could be a helpful tool for particle physics.
Dear Lutfa Rahman,
Greetings, Sorry, I mean " System of Particles".
Regards, Saeed
• asked a question related to Particle Physics
Question
is there a deeper fundamental property of neutrino oscillations? How does it work at the field level? is there any advanced mathematical connection or is only a physical fact?
I have a more simple view on the neutrino:
IMO the neutrino is a simple particle with a very weak interaction with matter. This weak interaction gives rise to only a few possible interactions in specific circumstances giving rise to neutrinos with different mass, i.e. there is only one type of neutrino but with different masses according to the interaction which created it.
As far as I know, the neutrino doesn't travel at light speed and, it doesn't follow the mass law "m=m_o gamma".
JES
• asked a question related to Particle Physics
Question
i want to know that going on in this topic and that could be the most important papers ,such as Scattering of two-dimensional massless Dirac electrons by a circular potential barrier and i only want to know more in this topic ,could yo give me an idea?
The cross-section is one of the topics of subjects in research in high physics energy.
The Compton scattering effect is the core of your question .
The two-dimensional Dirac electrons is one both the most problems in quantum mechanics ,this indicate to potential barrier
• asked a question related to Particle Physics
Question
Einstein's time dilation is determined with t’=t(1-v^2/c^2)^1/2. It is thought that the time dilation is confirmed with that the life of the flying mesons is longer than that at rest.
However, this is not true.
First, there does not be the stationary meson. Any particle is always moving. There are only the faster and slower moving mesons.
Second, no experiment for explaining the time dilation determined that what speed was used to distinguish the slower mesons from the faster ones. Or, in another word, are there the slower mesons? And, how much is the difference of the speeds between the slower and faster mesons?
Third, if there were the slower and faster mesons, the mesons are decaying according to a certain law. Thus, the life of some of the slower mesons is longer than that of parts of the slower ones. And, for the same reasons, the life of some of the faster mesons is longer than that of parts of the faster ones. Therefore, no life of both the slower and faster mesons is accordant with t’=t(1-v^2/c^2)^1/2.
dear Sir,
you are right in your investigations. a simple logic one can use in thundering sound and flash of light both occurring simultaneously in the sky, we receive first the flash of light (fast moving muons) and much later the sound (slow moving muons). in accordance with the experimental claim. due to time dilation we should have first received sound (slow muons) and much later the flash of light
• asked a question related to Particle Physics
Question
I recently found a publication that states extruded nanoparticles of roughly 120nm with +/- 1.21nm. This converts to a PDI of roughly 0.00011. Is this reliable? Or even possible?
The PDI reported in the Zetasizer software comes from the normalized second order term of the cumulant fitting. Assuming a Gaussian distribution the relation PDI = (sigma/peak mean)^2 holds.
The calculation is well-described in the international standards. For example ISO22412:2020 and ASTM E2490-09 (15).
• asked a question related to Particle Physics
Question
The fact that the measurement of vanishing distances is physically impossible, which preempts continuity, may lead us to not consider renormalization as a proper procedure in particle physics.
Also, it may lead us to disconsider it, as not needed to define derivatives using infinitesimals, and use Galois fields instead.
We may be pushing our equations too close, to limits where they probably do not apply, and renormalization just tries to solve the symptoms -- to avoid infinities. But the "problem" remains -- there are no infinitesimals in Nature, nor can be created.
Can we not use a concept that we cannot find nor encounter? Infinitesimals do not exist? Then, is renormalization necessary?
HS: thanks. But infinities and infinitesimals do not exist, so they are a pseudo problem. That’s what the question also says, that renormalization, in spite of its Nobel prize fame, is a pseudo problem. They are caused by assuming them to exist, and then "solving" them -- while they are already solved when using the correct formalism to start wit -- which is Galois fields. Nothing is continuous in Nature, not even numbers.
• asked a question related to Particle Physics
Question
Just attended some very interesting lectures as part of the "Higgs Fest" here at Uppsala (http://www.kalendarium.uu.se/en?eventId=4251), but while I think I understood how protons and neutrons gather mass from the Higgs field, I failed to comprehend how the electron gets its mass. - Would be grateful for any enlightenment for a physicist.
Schwinger discussed the electromagnetic mass of electron in his paper in 1983:
Note, this was written by the Author - Schwinger, who got Nobel price for QED theory containing infinities and renormalization of mass + charge of electron.
At present, Standard model assumes all the mass of the electron comes from its Yukawa coupling to the Higgs field:
• asked a question related to Particle Physics
Question
Quarks have emerged from the evidence that protons and neutrons are composite particles. This has led to the formulation of the QCD and the "asymptotic freedom" hypothesis. This theoretical framework explains the bond between nucleons. But the hypothesis of their existence has stumbled upon the impossibility of detecting them as free particles. The question is whether there is any experimental confirmation of their existence as components of nucleons.
Carlos Figueroa The answer to the question is no. But, at LHC, because Quarks are permanently incorporated with protons when these protons are accelerated at sufficiently high speeds the internal motion of the particles inside them gets nullified as per the special theory of relativity. So when head-on collisions of such highly accelerated protons are observed, new clusters of particles are scattered off in different directions and probably in near future, quarks singly would be observed this way because after the scattering it's very hard to hold them.
• asked a question related to Particle Physics
Question
the spin of Δ(1232) is 3/2 ,but its decay product,like nuclear is 1/2,pion is 0, so the spin isn't consistent before and after decay reaction .Is some of the spin angular momentun translate to orbital angular momentum?So what is the trajectory of a free particle that carries orbital angular momentum?
There's nothing particularly new to report about these resonances. The statement about the pion is wrong: it carries orbital angular momentum in theory and in fact. Its trajectory is described in terms of the cross section for observing it-more precisely its own decay products. The calculation is standard and described in any textbook on particle physics.
• asked a question related to Particle Physics
Question
One remembers, first, that all matter used in anything is constructed of atoms, where atoms are made of particles, where quantum mechanics (QM) physically works.
Any physics, chemistry, engineering, computer science, even mathematics -- where the electrons, light, wave, and number behaviors are determining these fields by Nature -- will obey quantum rules, such as NO "law of the excluded middle" and NO "axiom of choice", and where QM principles play main roles.
One reads, for example, at Stanford U. that: the concepts and techniques of quantum mechanics are essential in many areas of engineering and science such as materials science, nanotechnology, electronic devices, and photonics.
Nominations by participants here (in order of appearance) include:
Superfluidity, superconductivity, HVDC with QM rectification by a thyristor (semiconductor), incandescence, laser, quantum decoherence, entanglement, P-type or N-type semiconductors, transistor radio, and the entire known universe for 13.8 billion years so far.
What is your reasoned opinion? What is your best example of QM having visible effects on microscopic and macroscopic scales?
One thing that comes to mind in regards to your primary question is hydrodynamic quantum analogs. These experiments were done at MIT in July of 2013 published in Physical Review Letters E. Dr. Daniel M. Harris displayed that "a coherent wavelike statistical behavior emerges from the complex underlying dynamics and that the probability distribution is prescribed by the Faraday wave mode of the corral." I hope this helps!
• asked a question related to Particle Physics
Question
During my reading about interaction of particles physics, i found there are some interactions that is impossible to occur because, it do not conserve the energy. By more investigation about this point, found that the rest mass of input particles of these type of interactions is less than the rest mass of output particles so, i think now that don't conserve energy because the rest mass not conserved. Is my understanding is correct?
If it is correct, we can by more K.E for input particles make a chance to convert the extra energy (K.E) to mass in output particles and making these interactions are possible (from the equation that relate the energy and mass in relativity $E=m c^2$).
Finally, I have problem to understand the meaning of impossible interactions due to the conservation of energy. An example of these ineractions:
$\Sigma^{0} \rightarrow \Lambda + \pi^{0}$
Thanks
Hi Andre,
Thank you for your comments, regarding 'no longitudinal recoil' and neutrinos emission, etc., and ref. to your paper covering that, The Mechanics of Neutrinos Creation in the 3-Spaces Model. I think that clears up a misunderstanding I had, and the previous 'model' I entertained.
Best Regards, Carl
• asked a question related to Particle Physics
Question
I believe that Higgs boson is not a God Particle and there is much to unveil beyond it...
Thank you..
When it comes to particle physics, I believe that the most pressing questions nowadays are:
- Dark matter, to explain gravitational effects unexplained by the observable matter in the universe. However, maybe the explanation lies in a more advanced theory of gravity.
- CP violation, to explain the matter-atimatter asymetry of the universe. CP violation allows different cross-sections/production rates of particles and antiparticles. Considering the known particles, the Standard Model doesn't have enough sources of CP violation in its interactions to explain the asymetry. However, this is needed assuming that the universe was symmetric in its begining.
- Neutrino masses and if they are Dirac or Majorana particles. All we know is that the neutrino masses are very small (less than 0.1 eV), but we don't have an exact measurement due to current experimental limitations. Also, we don't know if neutrinos are their own antiparticles (if they are Majorana fermions) or not (if they are Dirac fermions). Finally, we don't know how they get their masses, because they can't use the higgs mechanism to do so given that there are only right handed neutrinos and left handed antineutrinos.
• asked a question related to Particle Physics
Question
Contemporary physics is from the view of particle physics a breeding ground for theories which quite misses a serious analysis of all the comprehensive facts collected over decades.
The amount of observed particles (called 'particle zoo') are not used to reconstruct the underlying structures of matter. Additional particles are invented instead by theoretical need. The own subjectivistic theories are described as the truth. There is a inability visible to face the facts. Contradictions are suppressed.
Physics is at a crossroads: Exact science or scientific founded faith.
nice notes
• asked a question related to Particle Physics
Question

As we know, many cosmologists argue that the Universe emerged out of nothing, for example Hawking-Mlodinow (Grand Design, 2010), and Lawrence Krauss, see http://www.wall.org/~aron/blog/a-universe-from-nothing/. Most of their arguments rely on conviction that the Universe emerged out of vacuum fluctuations.
While that kind of argument may sound interesting, it is too weak argument in particular from the viewpoint of Quantum Field Theory. In QFT, the quantum vaccuum is far from the classical definition of vaccuum ("nothing"), but it is an active field which consists of virtual particles. Theoretically, under special external field (such as strong laser), those virtual particles can turn to become real particle, this effect is known as Schwinger effect. See for example a dissertation by Florian Hebenstreit at http://arxiv.org/pdf/1106.5965v1.pdf.
Of course, some cosmologists argue in favor of the so-called Cosmological Schwinger effect, which essentially says that under strong gravitational field some virtual particles can be pushed to become real particles.
Therefore, if we want to put this idea of pair production into cosmological setting, we find at least two possibilities from QFT:
a. The universe may have beginning from vacuum fluctuations, but it needs very large laser or other external field to trigger the Schwinger effect. But then one can ask: Who triggered that laser in the beginning?
b. In the beginning there could be strong gravitational field which triggered Cosmological Schwinger effect. But how could it be possible because in the beginning nothing exists including large gravitational field? So it seems like a tautology.
Based on the above two considerations, it seems that the idea of Hawking-Mlodinow-Krauss that the universe emerged from nothing is very weak. What do you think?
A universe can be created from nothing without any external laser or strong gravitational field. In QFT vacuum real particles can be created and annihilated thereafter provided their lifetime dt and energy dE satisfy the uncertainty relation, roughly dtdE~h where h is the Planck constant.
Owing to the uncertainty relation, borrowing a small amount of energy (dE~0) from vacuum is allowed for a long time. According to some estimates the total energy (including negative gravitational energy) of our Universe is precisely zero or very close to zero. Hence, if the Universe is created as a quantum fluctuation its lifetime can be almost infinite.
• asked a question related to Particle Physics
Question
The great experiment at the LHC has proven the non-existence of quarks.
But current theories claim that 'quarks' are the decaying particles if β-electrons resp. β-positrons arise. If the theories of β-decays are wrong also W-Bosons, Z-Bosons and 'neutrinos' at issue.
Juan,
Physics has no choice as to start from scratch all over again.
The way to declare the observations, experimental results and at least the world by appropriate theories is the way of religions. The most theories of the 20th century are waste.
My Regards! Hans
• asked a question related to Particle Physics
Question
In my opinion velocities more than that of light are imaginary only.We can not observe velocities more than that of light.
Based on this imaginary concept how a field is described and got 'Nobel' for its predicted particle.
Means, the calculation of predictions by standard model and quantum field theory may be correct. But still the most fundamental of quantum mechanics need some modifications which may modify even the standard model also.I feel that these modifications may develop new concepts in cosmology, black holes, dark matter and particle physics.
After considering all your views about 'consciousness of atom' and 'smartness of atom' I felt that it is useless to continue this discussion for me. It is deviated from the topic in the question(a topic on particle physics). So I am not interested to discuss it further.
You may have another forum for its discussion.
All the best...
Regards.
• asked a question related to Particle Physics
Question
I recently prepublished this paper and deposited it on HAL (CNRS open archives):
What do you think ?
Papers to suggest in this area to cross opinions?
Wave-corpuscle duality is actually an historical concept. Already at the time of Newton were controversies on whether light is a wave or a particle. Now we have quantum mechanics but no historical continuity. It was falsely claimed for a long time that classical mechanics was a limiting case of quantum mechanics. It isn't, its limiting case is geometrical optics. A particle has wave and corpuscle aspects, but these aspects are quite partial. In fact we have a classical-quantal duality.
• asked a question related to Particle Physics
Question
Please someone tell me what is the difference in the Target material of world volume and sensitive detector material of chamber volume of B2 Basic example in Geant4 simulation?
I am using QGSP_BERT_HP physics list in B2 Basic example.
I am changing target material to Boron-10, sensitive detector material to Si and particle to neutron in B2 Basic example of Geant4.10.01. I am getting the secondary particles Lithium,alpha and gamma.
If I am changing sensitive detector material to Boron-10, target material to Xe and particle to neutron in the same example. I am getting the same secondary particle. Just at the output file in the bottom there are just displaying the energy deposition. Nothing else everything is the same as above.
I really want to know the difference in Target material and sensitive detector material in B2 Basic example?
Why the event 0 of run 0 does not have any hits despite it has many tracks. On the other hand event0 of run 1 has 352 hits @ Patrik Eschle
• asked a question related to Particle Physics
Question
They are just hypothetical particles.
Dear Natalia S Duxbury.
The axions would be a good candidate for the dark matter for two reasons:
they haven't electric charge and their interaction with matter is very weak. The main problem is that these only speculative particles never observed.
• asked a question related to Particle Physics
Question
While reading the introduction to the Interpretations of the DAMPE electron data, the introduction references how positrons and electrons in large amounts can be used to probe CR sources as well as dark matter. What makes the electron/positron special in this case? Why is it used as oppose to anything else? How is it used?
What makes electrons and positrons special in this regard is that they're the lightest leptons and that they have weak interactions. That's why they're useful probes of new processes-such as those involving dark matter particles, testing the ways these can have weak interactions. So, if it's possible to detect an excess of electrons or positrons that is beyond known backgrounds, this allows to describe possible decay pathways for dark matter particles.
• asked a question related to Particle Physics
Question
It is demonstrable that the chains of decay of muons and tauons finally ending in a single electron resp. positron. The intermediate stages of the different decays are caused on the one hand by the higher mass = energy and on the other hand on various internal energy of the decaying particles.
Therefore muons and espacially tauons show superior number decays what means that additional particles arise during decay. This additional particles are caused by pair production. The arising electrons/positrons are demonstrable the elementary building blocks of all particles and atomic nuclei.
Dear Stam,
1) quarks, gluons, gauge bosons et c. have never been detected, so how do you know anything of their structure?
2) theory of confinement; this is a very great commodity, in this way you don't need to explain why you haven't detected any of the quarks..
3) potential- charge; different signs on the charge change the direction of the force, why? The rest mass has some significant, in your eyes?
4) The force, I would like you to explain how the virtual photons can identify the direction and the velocity of a target charge, having a different direction and velocity than the source charge, and how the interaction from the target charge can find direction and velocity of the source charge and interact correctly?
5) As usual it is easy to explain something when you don't look into the details, or if you use a law including constants and parameters, without explaining why they have the value they have. It is not sufficient to say they have these values because
the experimental results are like this. That doesn't explain any fundamental physics.
• asked a question related to Particle Physics
Question
I need best simulation softwares for particle physics and nuclear physics
Dear Pavan Krishna,
GEANT4 is the best to use.
• asked a question related to Particle Physics
Question
I am looking forward to find a free source Monte Carlo toolkit that might be useful in elementary particle simulations. I need the help and advices of experts in Monte Carlo simulations.
FLUKA is very good in my experience and relatively easy to use. We have found it to be pretty accurate for energy deposition calculations.
• asked a question related to Particle Physics
Question
Modern Physics describes four fundamental interactions naming: Strong Nuclear Interaction, Weak Nuclear Interaction, Electromagnetic Interaction and Gravitational Interaction. Among other three fundamental interactions, the three major questions about gravity remained open;
Why the gravity is extremely weak? Hierarchy Problem
Why the gravity is always attractive force? Even anti matter is attracted to itself and to the matter.
Gravity is not unified with other interactions by successful theory like Chromodynamics or Weak Theory.
Hi Hewa,
some interesting replies here. I also think gravity and the other 'forces' are interactions. Gravity IS linked to quantum theory however, and to GR (read my article for example) which shows the electrostatic interaction is also related. Gravity = GE/c (squared) = [2 x phi (4th) x elementary charge x momentum]/pi (squared), among other expressions. I hope to also show how gravity links with the strong and weak interactions in the near future.
It appears gravity is a property or cost of having mass. Since many of the 'constants' run with the energy scale (e.g. the fine structure constant, gravitational constant, elementary charge) and they are all united via an 'interaction constant', we can have constant change (with energy) in the universe without changing principal ratios. Current 'mainstream' beliefs about masses of galaxies are incorrect, and when suitably modified by running constants, remove the need for ad hoc features like dark energy/matter. [It would actually be more fun, and no less correct to have dark chocolate filling space :)].
Like momentum, gravity is only a 'one-way' deal. You either have it, or not. If you don't, then you don't have mass or wavelength.
Gravity is only a 'weak' interaction in weak energy fields. At large energies (close distances) gravity becomes very strong. It is this aspect that fuels researchers to seek a theory unifying all the 'forces'.
Thank you for asking good questions.
regards,
Terry
• asked a question related to Particle Physics
Question
Dear All
Could you please guide me how to flip spins for A, C, and G type anti-ferromagnetism for and FCC lattice.
please see the attached Figure for simple cubic and FCC. I have drawn spin vectors for simple cubic but have no idea for FCC
Though you asked this question 3 years ago, and might be knowing the answer very well, I would like to paste a link here, may be useful for others.
also suggest to see this book
• asked a question related to Particle Physics
Question
Supersymmetry theory proposes that the super partners of the existing bosons and fermions are extinguished through some symmetry breaking mechanism… though there are some articles that offers few or no exotic particles other than the SM particles, but it would also be the case (in the theoretical model) that the symmetry breaking may cause polarization either only towards bosons or fermions… if not, why/how nature would choose which fermions and bosons among the super particles are to survive? Further, is it at least theoretically possible that the existing bosons and fermions have their super partners within the observed fermions and bosons? I do understand that in the second proposal the constraint of equal mass will be violated.
So far, the Supersymmetry has not been very succsesful in physics. However, mathematically, it is a very beautiful subject, which may explain why it stood so long with theoretical physics.
• asked a question related to Particle Physics
Question
According to common understanding the fundamental interactions of the standard model are mediated by the exchange of so-called gauge bosons (photon, gluon etc.). Now, the e.g. number of gauge bosons is related to the gauge group of the corresponding theory. But the wording "exchange particle" is apparently motivated by the graphical representation of Feynman diagrams. I wonder if we would talk and think differently if this tool of organizing your perturbative expansion would not have been invented.
By the way: the background of this question is the following: Since I believe that Feynman diagrams cannot be interpreted realistically, the notion of (virtual) exchange particles appears to me questionable (i.e. based on an artefact, like the specific solution technique of perturbation theory). But perhaps this “exchange” idea could be motivated also differently and independently.
Dear Oliver,
"...do physicists commit a fallacy in the Whitehead sense or are are we not in the arena of "logical reasoning"? "
That depends. Of course, we can argue logically with Feynman diagrams as long as we and our conversation partners know the mathematical terms symbolized by the lines and stick to the logic of the Feynman rules. Most physicists use Feynman diagrams in this way.
However, if the internal lines are "explained" as particles that are able to leave their mass shell, then this is a fallacy, because such explanations leave the logical arena of the Feynman rules.
Although well-intentioned, such pseudo-explanations are superfluous for the experts and give the laymen a false understanding of particle physics.
Walter
• asked a question related to Particle Physics
Question
I'm doing a particle physics analysis (jet energy regression) by means deep neural network (in keras with tensorflow backend). I have several features (mostly kinematic variables). I trained my model on the HH->bbbb samples (Di-Higgs decaying to 2 pairs of b and anti-b quarks). I normalized this dataset to zero-mean unit variance (z-score normalization). Now, I want to predict using a different sample (HH->2b2g, di-Higgs decaying to a pair of b quarks and two photons). When predicting this dataset, should I normalize it based on the HH->bbbb statistics? When I try to do it, it doesn't predict well, even giving me negative values of pT (transverse momentum (pT) should be > 0). Should I normalize HH->2b2g samples based on its own statistics instead?
Exactly, if you applied the z-score normalization, then just calculate the inverse transformation using your HHbbb statistics (multiplying predictions by the standard deviation and then adding the mean).
• asked a question related to Particle Physics
Question
quantum field theory says:::::: the vacuum state is not truly empty but instead contains fleeting electromagnetic waves and particles that pop into and out of existence.
then sound should travel through vacuum.......do sound travel through vacuum?
The interaction with the virtual quanta of the vacuum is very weak and the sound which is an atomic phenomenon reacts very-very weakly with those virtual states. The neutrinos also go through our bodies or the entire Earth with very few or no interactions.
The vacuum polarization has been observed in specific experiments with and atoms. Another interesting case for vacuum efects is the Casimir Effect.
• asked a question related to Particle Physics
Question
It is possible to analyse particle decays and their interactions to reconstruct the structures of particles and atomic nuclei in a realistic way. This leads inter alia to the result that atomic nuclei are grids of certain types of particles (light mesons) in the highest order according to the number of particles.
This lattice model described the properties of nuclei very good as the binding energy, the well-defined surface of nuclei, all types of decays and so on.
In particular, the usage of additional particles (quarks) which are invented on a theoretical way is not required.
Interesting.
• asked a question related to Particle Physics
Question
I am working a paper on it. The calculations based on Siva's Constant 'K' and Equations of particle physics may be useful in separating two Bio field particles(cause for consciousness) of a DNA existing out side of its main body by developing a Technic. This change in DNA out side body will change the Entire body.
If you believe my opinion or not. I want know your opinions on the above questions...
@Ananth Bommakanti
"technically one can get the gene and engineer future generations, but time travel i mean going into future is more Physical Science".
Genetic Engineering is purely based on genetic material and its sequencing. But for time travel we have to go beyond it. Genetic material is made up of molecules. Molecules made up of atoms. Atoms made up of elementary particles. Elementary particles made up of a single elementary particle which can not be divided further. If we try to divide that the space and time will be changed for the material containing that particles. So you are right that time is physical.
space time are inter related. Space can be converted in to space and vise versa. Quantum physics is based on probability which is due to the position of particle in its own space time where the particle oscillates between future and past.(There the importance of time place a role) If we tried to disturb it(force to be applied) the particle will oscillate in one portion of its space and will time will go in one direction(future/past).
DNA or RNA perse is not life
Yes DNA or RNA are non living chemical/biological matter only.In my words it is a 'link less' material from its 'living' matter. As explained in my papers and in above discussions, living and non living matters will have a difference in material structure. Thus living thing will have a signal current from universe from a particular point of cell and network will be connected to its centralized system(brain for humans). It can adept for life if it is attached again to the network. DNA and main body both will have same frequency(frequency in the sense living body and its DNA will not mach with other).
Unless you are talking about our conscience going to future rather than Physical body.
all the fundamental forces of nature will have different space times with different densities. Density can be calculated by 'K'. We are in gravity space time. So we are sensing our body as defined by biologists, chemists and physicists. The same will exist in all the space times. If we are in electromagnetic space time we can see this body with other elementary particles differ from gravity. In the same way the DNA can also exist in other space times with different elementary particles which are equivalent to our present structure.So body can be transformed in to other space time and can come back.
Sorry for the delay in reply...
• asked a question related to Particle Physics
Question
If the Higgs field were zero instead of 246 GeV, would the Higgs boson have the same mass? What if the field is metastable and the next stable value is much higher, say 10^10 GeV, would the mass of Higgs boson change at that value? And by how much?
Some people say that the Higgs gives the other particles mass, but that’s inaccurate (at best). The Higgs gives only about 2% of the mass of the matter around us in everyday live. The rest is provided by the spontaneous breaking of chiral symmetry and the trace anomaly in QCD. Within the standard model of elementary particles the condensate of the Higgs field provides mass to the quarks and leptons.
The Higgs field itself has a generic mass term by its own, but with the “wrong sign”, so that the local SU(2) x U(1) gauge symmetry is broken to U(1). The great discovery of Brout and Englert, Higgs, and Guralnik, Hagen, Kibble (all three articles in PRL 13, 1964) was that in the case of such a spontaneous breaking of a local gauge symmetry is an exception to Goldstone’s theorem that applies to global gauge symmetries only. In the case of a spontaneously broken local gauge symmetry the “would-be Goldstone bosons” are lumped into the gauge fields of the broken part of the symmetry group and thus provide the longitudinal third component of a massive vector boson, i.e., these gauge bosons become massive. In the case of the electroweak standard model that means that the SU(2) weak-isospin gauge bosons become massive (these are the three W and Z bosons), while the unbroken electromagnetic U(1) keeps its massless gauge boson (the photon). Excitations of the Higgs field above its vacuum expectation value (VEV) appear as physical particles in the theory, and that’s the Higgs boson. It gets its mass from the generic mass term and part of the Higgs-self interaction around the VEV. This leads to an effective mass term for the Higgs boson with the right sign. For the usual choice of a “minimal Higgs sector”, where the Higgs field is a SU(2) weak-isospin doublet (4 real field-degrees of freedom, of which 3 are providing the longitudinal components of the W and Z bosons and 1 describes Higgs-boson particles after spontaneous symmetry breaking).
In the original version of the Standard Model, the fermions are massless. When you try to add a mass term by hand, it violates gauge invariance. If there is a Higgs boson, there would have to be an interaction term between the Higgs boson and the fermions, and that interaction term has the same mathematical form as a mass term for the fermions would have, if there were a mass term, and so therefore you can use the interaction term between the Higgs boson and the fermions for the mass term for the fermions, and thus you end up with a mass term for the fermions.
• asked a question related to Particle Physics
Question
How can I calculate  the sterile neutrino frequency by Boltzmann equation and dY/dT ?
T is temperature
Radiative decay channel and decay rate are attached.
Define a variable z=M/T, where M is the mass of the lightest RH neutrino (sterile with respect to S.M). Then you can calculate B-L asymmetry NB-L which is related to Baryon asymmetry by a numerical factor (Harvey & Turner 1990) by solving a set of two coupled differential equations where independent variables are NB-L and and NN where NN is the number density of the lightest right handed neutrino. For that we have to define three rescaled variables, D=gamma_D/(H z), S=gamma_s/(H z), and W=gamma_W /(H z). Denomenators have nothing to do with frequency, however, it is ia product of Hubble constant and z. Then, the Bolzmann equations are,
• d NN/dz = -(D+S) (NN - NNeq)
• d NB-L/dz = -eps1 D (NN - NNeq) - W NB-L
eps1 is the CP asymmetry parameter.
• asked a question related to Particle Physics
Question
In the conclusion to the attached article I have categorized SR as metaphysics based on five reasons such as 1) insisting on thinking alone by promoting thought experiment rather than real experiment 2) creating thought instruments with unknown and inconsistent characteristics to do thought experiment, etc.
Do you think if this is a fair treatment of SR? Are all five reasons acceptable criteria?
The Principleof Relativity is the proposition that the laws of Nature are the same for all unaccelerated frames of reference. It was proposed by Galileo, not Einstein. Galileo presented it in the form of “thought experiments”.
The constancy of the speed of light in a vacuum is a conseuence of Maxwell’s electromagnetic theory. Since it is a “law of Nature” Galileo’s Principle should apply to it. Thus Einstein arrived at Special Relativity. He arrived at it and presented it, through “thought experiments”.
since then, the theory has been amply verified by real experiments. The role of “thought experiments” in Special Relativity is today only pedagogical. They are an aid to understanding, not an integral part of the theory. I cannot see how they render the theory “metaphysical”.
Vikram sees the “observer” in the theory as a “metaphysical entity”. I disagree. In the real world we all know what an “observer” is - a real human being perceiving things. When I encounter “the observer” while reading about relativity, I take that to mean a physicist equipped with any instruments he may require to recieve and send signals, to measure and record distances and times - not at all a metaphysical entity.
If the employment of “thought experiments” in formulating and understanding a physical theory renders that theory “metaphysical”, then all theoretical physics is metaphysical. Because no theory can exist in the absence of thought.
• asked a question related to Particle Physics
Question
"I thought about quantum mechanics a hundred times more than general relativity, but I still don't understand," Einstein said.
Perhaps the most difficult to understand is the wave-particle duality, which may be because the understanding of it is only in the form of mathematics.In fact, no one can actually verify the wave-particle duality, because the experiment can't verify a single photon.
Electrons orbiting the nucleus of the cycle and the volatility of the particles there are closely linked, we can think of chemical bonds between atoms and atomic are fluctuating, at a certain moment because electronic is only a position on the orbit, and from the time a constantly changing position, the this kind of change has the regularity.When two atoms of electrons near each other, two atoms repel each other, and when electrons in an atom near the nucleus of another atom when they will attract each other, so that can form regularity of volatility.
Inner surface cracks in the double-slit experiment of atom has been in a regular wave conditions, when the particle is trying to through the gap, when near the atom will be fluctuations in the perforated of atomic bomb, a reflection of photonic and electronic electromagnetic ejection in such a state of regular fluctuations, as the accumulation of time and the number of regular interference fringes are formed.The smaller the momentum of a particle is, the larger the Angle of the ejection is, the greater the spacing of the stripes, the longer the wavelength is.
Electronic counter near the double slit to observe, emitting a large number of photon hits the aperture inner surface of atoms, and makes the surface atomic wave interference, can be seen as inhibits such a state of regular wave, the particles will no longer through double slit by regular reflection and ejection, which in turn has emerged two bright stripe.
This is why increasing gap width will not cause interference and diffraction, because of the emitted particles and gap edge contact and collision probability becomes a matter of fact interference and diffraction and crack width, crack of fluctuations, particle momentum, launch position and the Angle of aperture.
No there isn't. All this is understood and taught in physics courses, so it would be useful to actually study quantum mechanics, instead of trying to guess.
These lectures: http://www.feynmanlectures.caltech.edu/III_toc.html might be a good place to start.
• asked a question related to Particle Physics
Question
We understand that moving particles have wave properties and waves have particle properties. Acceleration of particles in mono- or multiple target context creates waves, but wave creation includes constructive or destructive interference.
Can we explain the existence of radiation free multi particle objects like atomic nuclei, atoms or molecules with destructive interference of waves corresponding to the movement of the particles (atomic nuclei and electrons in case of atoms or molecules), which span the object?
Would this view be equivalent to or deeper as the view with the eigenvalues of the Hamiltonean or the Dirac operator?
Can we extend this view (for atomic nuclei and quarks) to a potentially endless series of higher order particles and higher order radiation? (The higher order radiation has to include destructively interfering particle emission.)
Dear Wolfgang
You write "the major difference between the wave function solution and a "resonance phenomena" solution would be the consideration of possible particle paths which lead to the same density profile as the wave function solution and additionally to zero radiation. "
You are absolutely right on all counts. In fact, the introduction of the wave function by Schrödinger was just a first step in precisely exploring the possibility of a precise axial resonance trajectory of the electron that would cause its motion to be contained within the volume defined by the wave function.
For example, the Heisenberg density probability profile of the hydrogen ground state orbital is consistent with a localized electron being stabilized in axial resonance state about a mean distance corresponding to the classical Bohr orbit in the hydrogen atom.
De Broglie wrote in 1924: " the wave of frequency ν with velocity c/β must be in resonance on the whole length of the trajectory. "
De Broglie L. (1923). Ondes et Quanta. Comptes rendus T.177 (1923) 507-510.
When you write "But the analysis of the dynamics of the transition between two atomic states can lead to new knowledge."
This is precisely what Schrödinger and de Broglie were proposing in 1924, but as soon as Heisenberg's statistical distribution gained favour, all research in this direction ware let go.
" To produce a coherent train of light waves of 100 cm length and more, as is observed in fine spectral lines, takes a time comparable with the average interval between transitions. The transition must be coupled with the production of the wave train... For the emitting system is busy all the time in producing the trains of light waves, it has no time left to tarry in the cherished "stationary states", except perhaps in the ground state."
And also:
"For it must have given to de Broglie the same shock and disappointment as it gave to me, when we learnt that a sort of transcendental, almost psychical interpretation of the wave phenomenon had been put forward, which was very soon hailed by the majority of leading theorists as the only one reconcilable with experiment, and which has now become the orthodox creed, accepted by almost everybody, with a few notable exceptions"
Einstein A., Schrödinger E., Pauli W., Rosenfeld L., Born M., Joliot-Curie I. & F., Heisenberg W., Yukawa H., et al. (1953). Louis de Broglie, physicien et penseur. A Tribute to Louis de Broglie for his 60th birthday, each colleague providing one chapter, Einstein even collaborating to 2 distinct chapters, the complete text drafting a detailed overview of the state of knowledge in fundamental physics in 1952. Éditions Albin Michel, Paris.
And also in :
Schrödinger E. (1952). Are there quantum jumps? Brit. J. Philos. Sci. 3 109,233.
You write: "A new finding even could be, that the model of moving particles is not applicable at all. For atom physics this would mean that atomic shells are specific fields, which have nothing to do with moving electrons. "
Right on again. From the electromagnetic mechanics perspective, an electron is not required to be in translational motion about nuclei, but can be stabilized in a least action axial resonance state in an atomic orbital within the volume to be described by a wave function.
Even Zitterbewegung can be related to an apparently stochastic (apparent only, in reality driven by interacting different harmonic oscillating electromagnetic quanta) magnetic interplay between the magnetic energy of the rest mass of the electron and the magnetic energy of its carrying energy.
I have a final paper coming up that will discuss in detail these considerations, but the essence of the development is given in this recent paper starting on page 14, if interested:
Understanding this new mechanics however involves complete reconsideration of the traditional concept of conservative momentum, and understanding adiabatic energy induction in all charges strictly as a function of distance by the Coulomb force.
Best Regards
André
• asked a question related to Particle Physics
Question
Reliable examples of second order phase transition have not been found. why? Second order phase transitions, L.Landau and his successors (by Yuri Mnyukh )
Phase transitions often break symmetries (this is the case of the Ising model). In these cases, the high temperature (low coupling) phase has typically the symmetry of the Hamiltonian H, whereas the low temperature (high coupling) phase shows a lower symmetry (and an enhanced order). Physically, this is because not all the states of H are “accessible” anymore by fluctuations energy wins over entropy in other words. The phenomenon that the system chooses one state during the phase transition is called spontaneous symmetry breaking. For example the Hamiltonian of the Ising model has a spin-flip symmetry, while the ferromagnetic state is either spin-up or spin-down. This symmetry is spontaneously broken during the phase transition as the system selects one of the two possible states as the ground state. The thermodynamic behaviour in each of the phases can be characterized by an order parameter, let us call it m (for magnetisation in the Ising model), and restrict to a scalar order parameter for simplicity (this is fine when discussing most order-disorder phase transitions). The order parameter m changes in a non-analytical way at the phase transition point. The order parameter is usually constructed in that way that m = 0 in the disordered state and m = 1 in a perfectly ordered state.
At first order phase transitions, the order parameter jumps discontinously at the transition temperature, typically Tc, from 0 to a finite value. This involves a latent heat ∆Q = Tc∆S: while T remains constant at the critical value Tc during the transition, the entropy S changes. As the energy in terms of the latent heat cannot be instantaneously redistributed, a mix of phases occurs during the transition (e.g. liquid water and ice at the melting point).
At second order phase transitions, instead, the order parameter increases slowly and continuously from 0 to a finite value at Tc. There is a discontinuity in the specific heat at Tc, while the correlation length and the susceptibility diverge at Tc.
• asked a question related to Particle Physics
Question
Hi all, we have begun a discussion about grovers search with method Clifford algebra, Can anybody make it clear to me?
Ofcourse it will be interesting, but I am little confused about grovers search. I guess you may be using graded algebras. Like to have details.
• asked a question related to Particle Physics
Question
What is the possibility that I'll get a PhD job for research in String Theory and Particle Physics? I'm currently in my 3rd Year of Undergraduate Studies and have done research work in Photonics. Due to unavailability of faculty specialized in relativity, cosmology, particle physics etc., I chose to do research in Photonics. To manage my interests, I studied relativity, particle physics from online resources. What are the chances that I'll get a PhD job at institutes like Perimeter Institute of Theoretical Physics, Institute of Theoretical Physics, Stanford, Kavli IPMU etc.?
Before you start investigating textbooks and study programs in fields of science, you should seriously contemplate whether you want to invest your life and talents in these areas.
The Standard Model of Particle Physics were completed in the mid-1970's. Try to explore which new, experimentally verified, ideas have emerged in the field of theoretical particle physics since then. Likewise, string theory was invented in the late 1960's and superstring theory during 1970's. Try to find out what these theories have contributed to observed physics.
The recent discovery of gravitational waves have opened new ways to explore cosmology and astro(particle) physics. This will hopefully lead to new insights and increased activity, both observationally and theoretically.
• asked a question related to Particle Physics
Question
The Standard Model of particle physics describes the universe in terms of Matter (fermions) and Forces (bosons). Particles of matter transfer discrete amounts of energy by exchanging bosons with each other.
Are these forces directly involved in the interaction between fermions (like collision)? In general, how we can describe the mechanism of exchanging bosons?
Dear Hossein,
The same with me. But to succeed in describing the self-sustaining mutual induction of electric and magnetic fields for localized EM particles, I found that the space geometry needed to be expanded to match the tripple orthogtonal electromagnetic relation.
• asked a question related to Particle Physics
Question
Subject: Particle physics (theory). I am looking for a way to transform v spinors into u spinors in a decay amplitude's expression. Does anyone have an idea? Thank you very much!
It is essentialy a harge conjugation transformationc. For the "standard" representation of the γ-matrices, the relation is v = γ2 u*. For more details google "charge conjugation of Dirac spinors". This should f.i. lead you to https://quantummechanics.ucsd.edu/ph130a/130_notes/node504.html
• asked a question related to Particle Physics
Question
"In physics, string theory is a theoretical framework in which the point-like particles of particle physics are replaced by one-dimensional objects called strings. It describes how these strings propagate through space and interact with each other."  -- Wikipedia.
One dimensional objects are not observed anywhere in nature. Strings are just an idea of locations best represented physically as the intersection of two surfaces. Vibration modes can be made to represent fundamental particles, depending on the character of the intersecting sources.
Infinities are not observed in nature either. There is no way to measure them. So in principle the structure of scientific theory cannot be derived from infinities.
The soundness of string theory is debatable. It needs 26 dimensions or a super symmetry of 12 dimensions. A family of Dark Matter particles is essential in the super symmetry, but the Dark Matter particles have not been found. I give the 26 dimensions a better chance of success.
For your question the answer should be no. Infinities do not help a physical theory.
• asked a question related to Particle Physics
Question
Is there any experimental evidence that some quanton (electron, neutron, proton, photon, so on) ever transmutes into a corpuscle ?
Lots and lots and lots of experimental proofs of their de Broglie wavelength, and Dirac-Schrödinger wave-length, of their de Broglie's intrinsic frequency mc²/h and Dirac-Schrödinger electromagnetic frequency 2 m c²/h.
Lots and lots of experimental proofs of their optical width and optical fuzzy length of each, depending on the experimental condition.
However, these experimental proofs contradict what is taught in every handbook, in every lecture room. What is taught is magical and mystic corpuscles, and calculations of the probability of apparition of magical corpuscle.
But when and how a photon transmutes into corpuscle ?
When and how a proton transmutes into corpuscle ?
When and how a neutron transmutes into corpuscle ?
When and how an electron transmutes into corpuscle ?
For instance, since 1921 the Ramsauer-Townsend effect proves that the electron IS its de Broglie's wave. So the Ramsauer-Townsend effect is heavily censured in every handbooks, in every oral teachings.
So on with the censures of the experimental facts.
Have you an experimental proof of the supposed corpuscles ?
@Yves Pomeau. What you call "wave function" has never existed in the real world. It is a fiction pecular to the Göttingen-København sect and its heirs, still three generations later. This fiction was initiated by Max Born, in order to save the mystic of "corpuscle". It uses the anti-relativistic postulate : the time becomes an universal and simultaneous parameter, like for the mystic god of Isaac Newton.
Please take some real world experimental facts, like the Ramsauer-Townsend effect (documented from 1921, and censured in every handbook of QM), the anti-reflect coatings, the quarter-wave plates for converting plane polarization into circular polarization, or the interferential colours exhibited by many birds, reptiles, fishes, so on, and their variations under large incidences.
All these experimental facts and many others give minorants to the diameters and length of photons, electrons, so on.
And now explain by which mystic and miraculous physics photons and electrons transmute into something corpuscular.
If never corpuscular ar all, why in the earth to devote so much efforts in denying their wave nature ? Why denying the wave mechanism of the Compton scattering ?
Why in the earth denyining so much the teachings of relativity ?
• asked a question related to Particle Physics
Question
I have a Feynman graph in t-channel with vector (X)-scalar(\phi)-scalar(\phi) vertex. Can someone please help me to find out what is the vertex factor for such a process and how can I calculate the matrix element for the same? I am attaching the diagram herewith (the scalars can be Higgs). Thank you in advance.
use this:
and look up any vertex you need or any feyman rules sorce (just make sure to use the same convention during all calculation), you also can you peskins QFT book. If the vertex is effective then you can calculate it using EFT (georgy's notes on EFT are good source) or just name that vertex somehow and do calculation.
• asked a question related to Particle Physics
Question
In two Higgs doublet model (2HDM), how the W and Z bosons get mass?  I am specifically looking for Type II 2HDM case.
Basabendu, take  φ10 and φ20 which are two neutral members of  φ1 and φ2. They will invariably mix with each other at electroweak scale because there is no other quantum number which will distinguish between them. Then form combinations cos α φ10+ sin α φ20  and  -sin α φ10 + cos α φ20. You will get an expression for the mixing angle α in terms of model parameters from the minimization conditions of Higgs potential.
In the Higgs potential, after substituting appropriate VEVs (for simplicity take them real) of two Higgs doublets, among other terms, you should obtain, (φ10)2, (φ20)2 as well as φ10φ20 terms with appropriate coefficients, which will form a 2x2 mass matrix in (φ10, φ20) basis. Upon diagonalization this matrix yields the mixing angle α in terms of model parameters. New basis obtained after diagonalization is actually the mass basis which you are seeking.
• asked a question related to Particle Physics
Question
"Dark matter" was undoubtful invented by theory. This type of matter should declare the shape of the universe 14E9 years after the assumed "Big bang" and it shuold have gravitational effect.
- The gravitation leads to aggregations of gravitational matter as fixed stars, planets, galaxies etc. Therefore "dark matter" cannot exist for the eternity in a finely distributed form somewhere in the universe. There are no observations of celestial bodies which consist of dark matter.
- Different types of gravitational matter should intermix. Why we cannot find traces of "dark matter" on earth? I remind the idea to search for "quarks" in the primary rock on earth.
(I therefore ask you not to link Wikipedia-articles or quote textbooks if possible. Someone who is the opinion that the present theories are right should open his own thread.)
The dark matter is an example of how science ever worked, but in the last 100 - 200 years even more then before. The wildest speculations are cited as science and in a short time people start to speak about such entities as their existence has been proven before. I prefer to look at the dark matter as an act of acceptance that we just haven't understood enough about matter so far. Nothing more. We speak about the universal gravitational attraction but in fact we have no idea about how universal it is. Maybe it works as known just at given scales and completely different at other scales. I don't want to mix the dark energy in this discussion, but just to remark that this concept is even more speculative than the dark matter...
• asked a question related to Particle Physics
Question
This question is initially limited to different types of particle matter.
The standard model assumed leptons, neutrinos, quarks and different bosons as fundamental particles. All the different types of particles have to consist of spezific types of matter with specific properties.
leptons – leptonmatter
electrons - electronmatter
neutrinos – neutrinomatter
quarks – quarkmatter and so on.
Furthermore different bosons, gluons, gravitons etc. and their spezific matters.
The assumption of many different fundamental particles leads to an inconsistency of the term of material matter and to some other inconsistencies.
Is the way to declare the real particles and atomic nuclei and their interactions by inventions of further imaginary particles a deadlock of theory? I remind that the different properties of atoms and their interactions are caused only by different structures of their electron shell and not by specific particles or abstract properties.
Sofia> Are you aware of these discoveries?
I don't claim to be fully updated on everything, but I have chatted a lot with Jens: https://www.ntnu.edu/physics/theoretical/astro
My project meeting today was with a PostDoc whose Ph.D thesis project was oriented around the hard-to-analyse QCD phase transition. And my last article has another former student of Jens as first author. This is an area where the basic equations are believed to be known, but where it is very hard to extract reliable consequences. 99.9% of physics is like that...
Sofia> There are two diagrams
In both cases all the discrete charges I mentioned are zero on both sides of the diagram. For baryon, lepton and electric charges because particles and antiparticles have opposite charges; for the colour charge(s) the story is too complicated to expose here. Colour charge is actually not additive, but behaves more like angular momentum, so I should formally not have included it in my listings (but that would also have been misleading).
Hans-G> The emphasis is on ...
I know we have (slightly) different emphasis, and I know how to correctly adjust for that.
Everything is much older than my ten last opinions about fundamental physics.
Note added: I don't  think it is fair to down-vote Hans on his own blog, for comments which are not that bad. I have up-voted, not because I think the posts really deserved it, but to compensate for what I consider unfair down-voting.
• asked a question related to Particle Physics
Question
Until now only Gell-Mann published  a significant  Picture of the particle physic:
the meson Sextett with the Strangeness +1,0 and -1 by crossing the 0 Point of the Spin-axis  with the incident Charge.
This 0 centre Point could now be the Higgs particle and the W+ and W- ray could be put together to the Charge-Axis. So we can get a Stereo Picture and a total System of the Standard Model "brick box".
Where could this System of the Standard model be published?
To prove the existence of the Higgs boson (that is, that the peak purported to be caused by the Higgs boson is really caused by the Higgs boson,) all of its quantum numbers must be measured, especially the spin that should be zero. Absent that, everything else has no interest.
• asked a question related to Particle Physics
Question
I am looking into how to set up a FTIR system to analyse InAs QDs embedded in GaAs and would like to know which geometry (Transmission or Reflectance) would be the best and cost effective for it. Does the sample placement either before the spectrometer or before the detector make a difference. Additionally, can FTIR be done with the sample placed in space instead of a sample chamber.
FTIR is normally performed with the sample between the interferometer (spectrometer) and the detector. So long as it is in the beam path, a specific sample chamber doesn't matter.
• asked a question related to Particle Physics
Question
How a particle is moving on a one dimensional lattice if we use a Discrete Quantum Walk?
Sanja,
a) How can you reach a one dimensional moving particle?
b) What is a "Discrete Quantum Walk" ?
Theoretically and genuine verbal are both the same!
• asked a question related to Particle Physics
Question
Assume two identical fermions, e.g. 3He, and polarized with the same spin projection, e.g. z-polarized. The fermions are sent from afar to the same detector - see attached picture. The dimensions Δx, Δy, Δz, of the detector and the precision of the linear momentum of the two beams, Δpx, Δpy, Δpz, satisfy the condition
(1) Δx Δpxħ, Δy Δpy < ħ, Δz Δpz < ħ.
The fermions come from a big distance s.t. at the detector the group-velocity of their wave-packets is the same and the wave-packets overlap.
As we know, two identical fermions, identically polarized, are forbidden to occupy the same cell in the phase space. So, what would happen with them? Would their linear momenta bend, so as to avoid one another?
A lot of thanks, Paul.
I believe that the real answer to this question is in the articles that you indicated: the fermions won't go to the same detector. When they get so close that they are about to satisfy the three inequalities in my question, i.e. to enter the same cell in the phase-space, they undergo scattering.
• asked a question related to Particle Physics
Question
Dear all, during the reading of Absorption and Scattering of Light by Small Particles,i find it difficult to understand the process of Mie theory's calculation for particles' optical efficiency. The question is the book refer to a simplification called far filed approximation based on an imaginary spherical particle. By using this approximation, what can we get? Or it is used for what?
In the far field (as Harry has correctly explained) we have Babinet's principle or assumption (or paradox) that the energy removed from the incident light beam by a particle is twice the particle's cross section (multiplied by the incident flux energy) - one unit removed by the shadowing of the particle and one by the diffraction of energy making 2 units in total.  This is where geometric optics (and for particles, the Fraunhofer approximation) applies.   Mie theory will show a (correct) maximum in the scattering coefficient dependent on the size and the relative refractive index..This scattering coefficient can be as high as 5 for TiO2 of 300 nm or so meaning that 1 unit of light energy is lost by the shadowing and 4 units by scattering/diffraction.  This makes TiO2 the most effective (hiding power) white pigment for paints.  See, for example:
August 11th 2011 Optical properties of the three forms of titanium dioxide
and:
October 9th, 2012 The importance of particle size, shape, and rheology in the paints, coatings, and pigments industries
• asked a question related to Particle Physics
Question
Consider a frame of coordinates F, in movement with a velocity V with respect to the lab. Assume that we prepare in the lab a beam of spin 1 bosons, polarized along a direction Q which makes an angle θ with the direction of movement of the frame F.
What will be the direction of polarization of the beam from the point of view of an observer in F?
In the classical mechanics the angular momentum is defined as Lr×p where r is the position of the object and p its linear momentum. To calculate L according to the frame F given r and p in the lab, is not a problem. But how to proceed with the spin. It's an intrinsic property, it is quantized.
Pauli-Lubansky  pseudo vector is defined as Wμ=1/2 εμνρσ Jμρ Pσ where J and P are angular momentum and linear momentum operators. WμWμ is a Lorentz invariant operator which commutes with momentum operator. Similarly PμPμ operator is also Lorentz invariant operator. These two operators can be used to label irreducible representations of the Lorentz group.  Because any elementary particle state should be a representation of the Lorentz group, we can label these states by their rest mass and intrinsic spin which are Lorentz invariant quantities; that is these numbers are universally valid for all those observers who are connected via  Lorentz transformations.
PS: by the term "Lorentz invariant operator" what we mean is that it commutes with generators of Lorentz transformation. "Intrinsic spin" angular momentum is the angular momentum of a free particle as opposed to the orbital angular momentum of a particle under the influence of an external force field due to it's presence inside an atom or in an atomic nucleus.
Note: If we change z --> -z i.e. a reflection then a spin up state will become a spin down state.
• asked a question related to Particle Physics
Question
we know that; Quantum entanglement is a physical phenomenon that occurs when pairs of particles are interact in ways such that the quantum state of each particle cannot be described independently of the others, even when the particles are separated by a large distance...Einstein and others considered such behavior to be impossible, as it violated the local realist view of causality.
it is the biggest problem of Quantum entanglement;
to overcome this problem, i am proposing here a new principle
“identical particles (fermions, bosons) cannot occupy the same position”. If identical particles occupy the same position; they are entangled particles.
that is, Quantum Entanglement is the subject of assuming all particles are at same position though they are separated by large distance!
my assumption is correct or wrong is decided by an experiment or evidence.
evidence: if entangled particles communicate instantaneously, my assumption is absolutely correct and causality problem also solved.
for more details go through attached link....
i am requesting to all unique scholars please comment on this..
Entanglement is not a problem for causality, althought you know the value of some characteristic of a particle farther way than light can travel, there nothing you can do with this informatio that affects causality.
• asked a question related to Particle Physics
Question
I know that
1) Majorana fermions are the antiparticals of its own and the Dirac particals are not anti particals of their own
2) Weyl particals are the half charged Dirac particals.
But how can i understand these concepts using DFT methods
Fermions can be described through the Dirac, Weyl or Majorana representations. According which representation you chose, you are able to study different properties of fermions. For instance if you chose the Dirac representation of electrons, you will be able to describe electromagnetic properties of them. Instead of this, if you chose the Weyl representation, you will be able to describe weak interaction of electrons. So you can write down the Lagrangian density in the representation you want and you can quantify with the method you like.
• asked a question related to Particle Physics
Question
my dear unique scholars i am requesting to comment on my new research result. so please comment on this.
We differentiate two electrons present in a same quantum states in terms of ℓ, the angular momentum quantum number, mℓ, the magnetic quantum number, n, the principal quantum number, and ms, the spin quantum number.
Now you have to add another difference called ‘position’. That is, identical electrons cannot occupy the same position.
modified Pauli Exclusion Principle:
Now I generalize The Pauli Exclusion Principle as “identical particles (fermions, bosons) cannot occupy the same position”.
If identical particles occupy the same position; they are entangled particles.
for suppose, if two electrons reside in the same orbital implies; those particles are entangled particles.
International Journal of Gathering Hypothesis is not a journal which is indexed by the American Mathematical Society (Math Sci.Net database). I also  do not see this journal at the ADS database http://adsabs.harvard.edu/cgi-bin/nph-abs_connect?return_req=no_params&author=Kholodenko,%20Arkady%20L.&db_key=PRE  where I am a regular contributor.  I do see, however,  that journal website claims that it is listed at the ADS database but I've checked this (ADS) database and was not able to find traces of this journal. While giving you an advise I had in mind ONLY journals listed in these databases
• asked a question related to Particle Physics
Question
I am working on charge particles production by DT neutrons. I need to calculate the energy loss correction of charged particles in the sample materials. There are codes like Perten, Crawl, Connect which perform the same. If anyone has used any of these codes or something else then let me know. I am unable to get anyone of these code.
Dear Mayank,
this should be rather easy using the Bethe-Bloch formula. Here's a link to the review from the Particle Data Group:
Best regards,
Alexander
• asked a question related to Particle Physics
Question
"A crayfish was put in a sea water basin from which calcium carbonate had been removed by precipitation; the animal made its shell anyway." //... "Chemical analysis made on animals secreting their shells has revealed that calcium carbonate is formed on the outer side of a membrane although on the opposite side of the membrane, where matter enters, there is no calcium. This fact has left specialists perplexed." (Kervran 1972, p.58)
There has long been debate on this - Kervran's proposition is that crabs routinely transmute magnesium into calcium; Mg + O => Ca.
Kervran (1972, p.52) described experiments performed in 1959 by the French government in the Sahara desert. The government was interested in determining the nutritional requirements of petroleum workers in the extreme heat prevalent in the desert. The second experiment lasted for 240 days and was conducted near Tindouf which has a drier climate. This time each man excreted each day an average of 256 milligrams of magnesium more than he ingested. Under these conditions, after 20 days, each man should have been completely depleted of magnesium; but somehow they survived for 220 days thereafter. It seems difficult to avoid the conclusion that the human body is able to create magnesium.
Kervran, C. Louis. Biological Transmutation. New York: Swan House Publishing Company, 1972
"Ig Nobel" prize 1993
... everywhere I read of this I see a lot of animosity_skillfully_disguised_as_irony. In fact too much for it not to raise an eyebrow.
In http://dx.doi.org/10.1007/s10773-009-0124-9 I show that certain 2-body interactions allow an energy minimum also in a 3rd state (non-fermionic, non-bosonic), which allows entanglement oscillations.
Since the nucleus is all about "condensation" (n-fermions give a lot of gammas before they come together as 1-system, as a 100% entangled state), it is conceivable that bodies that possess said "certain" interaction-type can move on "palier"-states (iso-energetical), but varying in wave-function overlap. [i.e. - dis-entangle]
Iso-energetical part-dis-entanglement (and part-re-entanglement) conceivably could mean transmutation.
Any thoughts on this ?
Remi is right.
The science is differ from religion - it's incorrect to say "just read this sacred book!" in scientific seminar. If you say "theoretically, it is possible", you must show a way - how?!
All biological processes are going on the level of valent electrons, nuclear processes stay away on energy scale. The statement about the possibility of biological nuclear reactions is extremly strong and, obviously, it is necessary to have very serious proofs.
• asked a question related to Particle Physics
Question
We know that ${\gamma_{mu},\gamma_{nu}}$= 2 $g_{\mu\nu}$, where $g_{\mu\nu}$ is the flat metric . That shows spinors are someway related to the metric of space. Can anyone please explain how?
In a curved space metric becomes position dependent gμν→gμν(x).
In a MInkowski space, which is a flat space, Lorentz transformations are global transformations. In a curved space-time Lorentz transformations act differently at each point where one uses the flat tangent space at each point. Therefore one sees that here Lorentz transformations become local. In a curved space-time if a theory contains spinors, then the theory should be invariant under local Lorentz transformations. They are gauge theories of the Lorentz group.
One has to study how Dirac spinors transform locally under the Lorentz group, and the Lorentz covariant derivative which acts on spinors.
• asked a question related to Particle Physics
Question
The quark theory assigns certain quark combinations to the different particles, par example:
Proton p = (uud)
Neutron n = (udd)
ngative delta Δ– = (ddd)
ngative omega Ω– = (sss)
Provided that the quark theory is right, why shold be quark combinations like (ud), (us) or (ds) not possible?
Quarks transform as 3 of SU(3). One can take products of these representations as
3 x 3 = 3bar + 6
3 x 3 x 3 = (3bar +6) x 3= (1+8)+(8+10)
We see that 3 x 3 does not contain a singlet but 3 x 3 x 3 does contain a singlet. Because all terms in the Lagrangian density should be Lorentz invariant and gauge invariant, one cannot have a term like, ud, us or ds.
• asked a question related to Particle Physics
Question
The equation is in the attached file. I would appreciate even approximate solutions with accuracy higher than the Fokker-Planck approximation.
@ Aleksei Bykov: Right, the equation is simplified by introducing x=cos(theta). However, the resulting equation for f does not seem solvable with an arbitrary function g(t, r).
I am mostly interested in the behavior of f at t >> \tau, where the equation can be reduced to the diffusion equation. However, a higher accuracy is desired.
• asked a question related to Particle Physics
Question