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# High Energy Physics - Phenomenology - Science topic

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Dear colleagues,

Do you have an idea about the source of light through which we see dreams ? and what is the source of light through which we can see the colors we see in dreams?

I wish you all the best

Huda

Actually,I am trying to plot relic abundance of warm dark matter in (2,3)ISS in mathematica 10 and having this problem.I need to diagonalize this heavy Dirac matrix inking Right Handed and sterile states as demanded by the formula which is not diagonal.I have done it for (3,3) ISS with no problem.So,how is it possible?looking forward to your answers.

Majorana fermions do not have vector interaction and hence there is no spin-independent direct search cross section for majorana like WIMPs. Can anyone please show me the proof ?

Can the electron spin reverse? What implications would this bring in terms of defining matter?

If we see the standard model particles, total decay width is 10% or much lower than its mass. One example, for 125 GeV standard model Higgs boson, its total decay width is 4.07*10

^{-3 }GeV. It's almost .0032%. Suppose we have a particle of mass 3 TeV. Can its total decay width be 1 TeV or say 2 TeV. Is there any constraints ? If so, please explain.The top and Higgs mass determination arose the old discussion about electroweak vacuum metastablity. There is an interesting fact that with available data or universe place in the edge of stable and meta-stable zone tends to be inside the meta-stable region. This conclusion confirms up to 3-loop renormalization group and even shows convergence. I know that changing the electroweak vacuum propertionally changes the top and higgs masses. But what I cant realize is that how the stability and meta-stability boundaries move. So to speak, can the universe become stable by new high energy physics emergence as <h>=246Gev replacement?

The Nobel Prize in Physics 1965 was awarded jointly to Sin-Itiro Tomonaga, Julian Schwinger and Richard P. Feynman "for their fundamental work in quantum electrodynamics, with deep-ploughing consequences for the physics of elementary particles".

QED rests on the idea that charged particles (e.g., electrons and positrons) interact by emitting and absorbing photons, the particles that transmit electromagnetic forces.

**These photons are “virtual”**; that is, they cannot be seen or detected in any way because their existence violates the conservation of energy and momentum.In quantum electrodynamics (QED) a charged particle emits exchange force particles continuously.

**This process has no effect on the properties of a charged particle such as its mass and charge. How is it describable?**By the 1950s, when Yang–Mills theory, also known as non-abelian gauge

theory, was discovered, it was already known that Quantum Electrodynamics (QED) gives an extremely accurate account of electromagnetic fields and forces. So it was natural to inquire whether non-abelian gauge theory described other forces in nature, notably the weak force and the strong or nuclear force. The massless nature of classical Yang–Mills waves was a

serious obstacle to applying Yang–Mills theory to the other forces, for the weak and nuclear forces are short range and many of the particles are massive. Hence these phenomena did not appear to be associated with long-range fields describing massless particles. In the 1960s and 1970s, physicists overcame these obstacles to the physical interpretation of non-abelian gauge theory. In the case of the weak force, this was accomplished by the Glashow–Salam– Weinberg electroweak theory. By elaborating the theory with an additional “Higgs field,” one avoided the massless nature of classical Yang–Mills waves. The solution to the problem of massless Yang–Mills fields for the strong interactions has a completely different nature. That

solution did not come from adding fields to Yang–Mills theory, but by discovering a remarkable property of the quantum Yang–Mills theory itself, called “asymptotic freedom”.Asymptotic freedom, together with other experimental and theoretical discoveries made in the 1960s and 1970s involving the symmetries and high-energy behaviour of the strong

interactions, made it possible to describe the nuclear force by a non-abelian gauge theory in which the gauge group is G = SU(3). The non-abelian gauge theory of the strong force is called Quantum Chromodynamics (QCD). But classical non-abelian gauge theory is very different from the observed world of strong interactions; for QCD to describe the strong force successfully, it must have at the quantum level the mass-gap and related color confinement

properties. Both experiment—since QCD has numerous successes in confrontation with experiment—and computer simulations carried out since the late 1970s, have given strong encouragement that QCD does have the properties of mass-gap and color confinement cited above. But they are not fully understood theoretically. In the attached link, http://dx.doi.org/10.13140/RG.2.1.1637.3205 the theoretical understanding of mass-gap and related color confinement property have been provided during mathematical calculation of the gluon emission cross section for QCD process by taking over the corresponding results from closely related aforesaid QED process under the assumption that color interactions in perturbative sector are “a copy of electromagnetic interactions.

As such, the direct mathematical calculation for QCD process has been

avoided because the presence of point-like Dirac particles inside hadrons through Bjorken scaling and the carriage of a substantial portion of proton’s momentum by neutral partons, as revealed by the ‘asymptotic freedom’ based analysis of the data on deep inelastic scattering of leptons by nucleons, do not constitute direct evidence that the aforesaid Dirac particles and neutral partons can be identified with quarks and gluons respectively for making QCD the correct physical theory.

The OPERA-experiment used as detector material 1300t of lead. One of its isotopes is 82-Pb-204 with frequency of 1,40% and half-life period of 4,42E+21s. This isotope decays according the following equation:

82-Pb-204 → 80-Hg-200 + α (iow: 82-pb-204 → 80-hg-200 + 2-he-4)

About 6000 high-energetic α-decays, each followed by some γ-rays happen in the detector material per second. Every α-decay caused a cascade of particle-interactions. Some of this interactions can be the same as the assumed neutrino-interactions.

Is a periodicity visible in the records of the detectors, correlate with the proton-pulses on CERN?

Or do the OPERA-detectors merely observe a natural background noise?

Do the highly precise time-measurement select only assumed neutrino-events?

We know in quantum mechanics position and momentum of a particle do not commute. But in a quantum field theory they must commute if position operator and momentum operator are separated by a space like separation in Heisenberg picture. In general [O

_{1}(x), O_{2}(y)] = 0 ∀ (x − y)^{2}< 0, has to be true. How is this ensured in a quantum field theory ?Second part of the question: Is it also possible to mathematically formulate an equivalent statement of microcausality in the Schrodinger picture ?

Sterile neutrinos can be a candidate for warm dark matter. Recently the news on 7keV sterile neutrino with negligible mixing have raised a few questions about the non resonant production of the sterile neutrinos, since such a small mixing is insufficient to produce the correct dark matter relic density. However, resonant production are possible which takes into account lepton asymmetry. In this context I was wondering if there exists a definite relation between the lepton asymmetry and the relic density.

Action at a distance is the simplest non-local interaction. But then in relativistic local field theories signals cannot travel at velocities more than the speed of light. This is taken into account by the introduction of force mediating vector and scalar fields. However in a 5 or higher dimensional model, we do not know whether signals can travel faster than the speed of light in the 5th coordinate which is (of course) compact. Such effects can only be seen at an energy scale 1/R, where R is the radius of compactification of the extra dimension.

We would like to know of some

**simple examples**of non-local interactions, which are generally discussed in the context of extra dimensional models.Is it true that all non-local interactions imply action at a distance ?

We do not know whether the neutrino is a Dirac particle or a Majorana particle. If neutrino turns out to be a Majorana particle then two additional phases are to be introduced in the 3x3 lepton flavor mixing matrix. Why these phases cannot be removed by field redefinitions. In the two generation case, we know that in the CKM matrix there is no CP violating Dirac phase. Similarly, will the Majorana phases disappear in the two generation case, or, will they continue to be non-zero even in the 2x2 mixing case. In which experiments will they show up.

References:

- J. Schechter and J. W. F. Valle, Phys. Rev. D 23, 1666 (1981)
- J. Schechter and J. W. F. Valle, Phys. Rev. D 22, 2227 (1980)

I have started to study the AdS/CFT correspondence by reading Minahan's introductory review (arXiv:1012.3983). The first equation of that review is the expression for the leading contribution to the $\beta$-function:

$$

\beta(g)=-{g^3\over16\pi^2}\left({11\over3}N-{1\over6}\sum_iC_i-{1\over3}\sum_j\tilde C_j\right),

$$

where $C_i$ are quadratic Casimirs due to bosons and $\tidle C_j$ are those due to fermions. The author cites Gross and Wilczek (1973) as a source of the formula. But there it looks a bit differently:

$$

\beta(g)=-{g^3\over16\pi^2}\left({11\over3}N-{4\over3}\sum T_j\right),

$$

where $T_j={d(R_j)\over d(G)}\tilde C_j$, $d(R)$ and $d(G)$ are dimensions of the representation and of the group.

Forget about the boson contribution (Gross and Wilczek were not interested in it). But the fermion contribution contains there the factor $-4/3\times{d(R_j)\over d(G)}$ instead of $-1/3$ in Minahan's article. The factor 2 is related to the fact that Gross and Wilczek considered Dirac fermions, while Minahan considers the Weyl fermion. Ok. But we are left with the extra $2{d(R_j)\over d(G)}$ factor, which I am unable to cancel.

Could anybody explain me this factor? May it be related somehow to supersymmetry?

The observed Lithium abundance is in disagreement with the standard big bang model. What are the possible solutions to the problem? How much the observations are reliable in this case? Is it possible to exist a method of destruction of Li that we don't considering or it is beyond standard model phenomenon?

Is anyone familiar with any sort of theoretical explanation of the number of chiral families? Any model or idea in this direction would be very interesting and useful.

Nature of dark energy is unknown. It is a form of energy causing expansion of universe. Satellite based experiments such as Planck has estimated that 68.3 % of total matter and energy is in the form of dark energy.

Concept of the equation of state perhaps originated in the study of thermodynamics, describing a relation between two or more state functions such as pressure, volume or temperature. These state functions are macroscopic variables.

How can one formulate an equation of state for dark energy? How do different theories lead to different forms of the equations of state of dark energy ? How can we experimentally test or distinguish between different forms of the equations of state? Are there proposed or ongoing experiments aiming to understand equation of state of dark energy ?

Some say the standard model is stable by the Planck scale, some others claim we must have new physics at the TeV scale, and some claim we need axions (and what else?).

What is the minimum number of new discoveries that is really needed to answer these unexplained observations?

A 7 keV sterile neutrino is a good candidate for warm dark matter.

What are the feynman diagrams by which a 7 keV sterile neutrino can be produced?

What are the decay channels? By which diagram can it decay to 2 photons so that a sharp line at 3.5 keV can be seen?

Vacuum expectation value (VEV) of the Higgs scalar is responsible for fermion

masses and also masses of the W+ W- and Z gauge bosons. Does it mean

that the Higgs particle can extract energy out of vacuum and convert it to a

new form in which gauge bosons and fermions are massive ? For quarks

one can also have QCD correction to masses which are

unrelated to Higgs VEV

Inflaton is the scalar field that causes inflation. Why it is assumed that it is a scalar field with very weak interaction?

LSND experiments observed oscillation between ordinary and sterile

neutrinos. Does the Mini-Boone result confirm LSND data ?

Inflation is a very attractive theory by which one can explain horizon

problem and flatness problem. A successful theory should have

experimental tests. My question is that what is the way to get some

prediction of inflationary theory tested.

Curvature of space can be estimated from Planck satellite data 2013.

There are several small satellite galaxies of milky way. Namely, Draco, Sextans, Carina, Fornax and others. What do we know about how dark matter is distributed in these satellites? Do we know about the amount of dark matter contained in these galaxies?

Any technical or non-technical information is welcome.

Unless there is a symmetry reason to protect the Higgs mass near the

electroweak scale, one loop effects will give large corrections. Is it

super-symmetry or is it something else ? Or is it some extra dimensional

mechanism which is working ? Or is it purely fine tuning of parameters ?

Dark matter density should vary with radial distance to explain flat

rotation curves seen in typical spiral galaxies like the milky way.

What are the popular density profiles. How do they fit with observed

data of the velocities of stars within a galaxy ?

Experimental search for dark matter must rely on some model which tells us how our instruments, which are made of ordinary matter, interact with dark matter. Otherwise we cannot invent the right instrument to detect dark matter.

We know quarks and leptons (including electrons and neutrinos), which make up what is classically known as matter, are all fermions with spin-1/2. The common idea that "matter takes up space" actually comes from the Pauli exclusion principle acting on these particles to prevent the fermions that make up matter from being in the same quantum state. It is also this pressure which prevents stars collapsing inwardly, and which, when it finally gives way under immense gravitational pressure in a dying massive star, triggers inward collapse and the dramatic explosion into a supernova.

Furthermore, elementary particles which are thought of as carrying forces are all bosons with spin-1. They include the photon which carries the electromagnetic force, the gluon (strong force), and the W and Z bosons (weak force).

But elementary fermions with other spins (3/2, 5/2 etc.) are not known to exist, until now and elementary bosons with other spins (0, 2, 3 etc.) were not historically known to exist, although they have received considerable theoretical treatment and are well established within their respective mainstream theories. In particular theoreticians have proposed the graviton (predicted to exist by some quantum gravity theories) with spin 2, and the Higgs boson (explaining electroweak symmetry breaking) with spin 0.

I want to know how 5 phases get absorbed in the quark fields?

This question true for PMNS also.

Suppose Least Count (LC) for some apparatus say 0.1 . But often we used to write 0.1/2 as least count. How this factor "1/2" come into the picture of LC ? We cannot able to measure anything beyond LC by definition. Then why this "1/2" ? Off topic but if you know the answer, please share so that I can understand it clearly...

It is mentioned in many textbooks that cut-off regularization scheme is not Poincare invariant so one has to look for Lorentz invariant schemes like Pauli-Villars, Dimensional regularization schemes. But how one can show using Poincare transformation that cut-off regularization is not Lorentz invariant?

I know that a mass term for an intermediate boson is not compatible with the gauge symmetry. But in principle a mass term for the Dirac field does not violate a gauge symmetry. However to build an electroweak theory consistent with the observation of the non conservation of the parity of the neutrino, the mass Dirac field could not be included and it also adquire mass due to the Higgs mechanism. There is some Standard Model particle having an explicit mass term or all acquire mass, as a result of spontaneous broken of the gauge symmetry and its coupling with the Higgs field?

Reading the Scientific American article (see link) there is suggestion that ATLAS observed not just one Higgs boson but two of them with a ~3 GeV mass difference. The lighter decays to ZZ while the heavier to 2 x photon. My first thought is that it is just a statistical fluctuation and that there is actually only one observed Higgs boson. Any thoughts? Could there really be two of them?

Antiparticle is regarded as 'going backward in space-time'. For some fraction of time positron had been detected by Anderson in cosmic rays. Was it the result from future event?