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# Theoretical High Energy Physics - Science topic

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Questions related to Theoretical High Energy Physics

We did not identify the black hole in full detail yet. Does it has an event horizon or apparent horizon. We are trying to modify our theory to resolve the problem of singularity. Is the black hole without singularity still be a black hole? What is the main character of the black hole, the singularity or the event horizon.

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?

Observational data indicates that the cosmological constant has a positive value, resulting in a de Sitter spacetime. In loop quantum gravity, the IR divergences in the Ponzano-Regge model can be made to disappear through q-deforming SU(2) to SUq(2). The classical limit of this Turaev-Viro model is GR with positive cosmological constant.

On the other hand, anti de Sitter spacetime has a number of (potentially) desirable properties as well, for example the AdS/CFT correspondence. This correspondence is used in Light Front holographic QCD and seems to offer some insights into confinement as well as meson and hadron spectroscopy (arxiv:1407.8131). AdS also admits a positive energy operator making it more suitable for a particle interpretation. There has been some work (mostly by Flato and Fronsdal) describing photons and leptons as composites of singleton representations that live in an AdS spacetime.

Would it be possible and sensible to describe spacetime as being anti de Sitter at very small scales and de Sitter at cosmological scales? Perhaps this would be possible through a bi-metric model?

To me it seems that such a model would offer the best of both worlds (LQG without IR divergences, agreement with cosmological observations, AdS/CFT, singleton representations). I am just not sure if such a model would be possible and if it even makes sense to think along these lines. I would very much value any comments people may have.

Thanks in advance!

You have a well-insulated box filled with sodium vapor. The box has been left for a long time. Suppose you punch a small hole into the box and observe the energy distribution around the strong yellow sodium lines at 5896 A and 5890 A. What would the energy distribution look like? Would you see spectral lines? If so, would you see absorption or emission lines?

What is the parameter or mechanism that needs to be considered in order to design a spacecraft that could bend and stretch the fabric of space-time?

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?**It is well known that Bohr model is not totally right. But I recently discovered a very curious inconsistency (if I am right) which I haven't seen explained anywhere.

The first postulate of Bohr theory is that the Orbital momentum of the electron is quantized L=mvr=nh (where h means the Dirac constant). This means that if there is a transition between level n=5 to n=1 (Balmer series) the orbital momentum changes by 4h !!! Based on this rule and his second postulate Bohr finds the right energy for this transition (and all others as well). But this transition is a release of just one photon and a photon has spin 1h . It can add to L as (h,0,−h) . So it can change the orbital momentum with 1,0 or −1 and not by 4. I'm very surprised to make such conclusion.

Am I wrong here?

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.

W

_{R}mass is constrained from K_{L}-K_{S}mass differences in LR model.What does it mean and from where it comes? A detailed calculation will be helpful.LR - Left Right

W_R - right handed W boson

K

_{L,}K_{s}- K-Long and K-short,two neutral kaon stateWhen we compare various cosmological determinations of neutrinos masses, Primack et al, 4.8 eV (1994); Allen et al, 0.6±0.3 eV (2003); Battye et al, 0.3±0.1 eV (2014) and finally Palanque-Delbrouille et al, 0.02±0.06 eV (2015), we see that the results have kept changing in the course of the time; moreover, they contradict each other.

However, the most recent one, appeared after Planck data, is quite impressive and agrees with the conventional picture of the neutrino mass spectrum, expected to obey a hierarchical pattern, and that implies the lower bound of 0.05 eV.

Evidently, this result is of great importance for the search of neutrino mass in laboratory. Do you consider the new result from cosmology reliable? Which systematic effects could threaten it? And, assuming it is correct, how could we test it in laboratories?

Reference to the new work:

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?

Researchers in the fields of cosmology and gravitation, which are also expert at high energy physics .

**A fuller statement of the question:**

What consequences arise (regarding nature or theories) if some of the 10 Poincare-group generators do not correlate with behavior of Z and W bosons, and/or (hypothetical) gravitons?

**Background:**

I may have developed math sufficient to provide an analog for elementary particles to the periodic table for elements. To the extent the resulting catalog of particles pertains to nature, it provides (for all 17 known ordinary-matter particles, some yet-to-be-found ordinary-matter particles, dark-matter particles, dark-energy particles, gravitons, and some other zero-mass bosons) spins, some information about interactions, some masses, numbers of generations (for fermions), and relevant numbers of generators related to the Poincare group (and special relativity).

**Findings:**

- The following particles would correlate with all 10 generators of the Poincare group: leptons, photons, the Higgs boson, and composite (yes, not elementary) particles such as pions and protons.
- The following particles world correlate with 7 generators of the Poincare group: Z boson, W bosons, graviton, and some other zero-mass bosons.
- The following particles would correlate with symmetries other than those discussed above: quarks, gluons, and some other particles.

**Parallel question:**

To what extent would the above findings violate known experimental or observational data?

**Reference:**

"Theory of Particles plus the Cosmos," especially table 2.8.2 in section 2.8. (See attachment.)

Kuhn says leading physicists accepted Newton's theory of gravitation before astronomical measurements were accurate enough to decide the issue ["Structure of Scientific Revolutions" 1962]. Other than this aged example, is there any case in which physicists accepted a new or modified basic theory of physics based on a mathematical derivation from well-accepted theories, before direct empirical evidence was available? The Higgs boson and cosmic inflation have something of this flavor: these theories had substantial credibility before empirical evidence was available because they explained phenomena that were left unexplained by existing theories, but they were not fully accepted in the canon of physics.

Domain walls or boundaries are expected to form when a discrete symmetry is broken spontaneously.

REF:

Y. B. Zeldovich, I. Y. Kobzarev and L. B. Okun, Zh. Eksp. Teor. Fiz. 67 (1974) 3

[Sov. Phys. JETP 40 (1974) 1]; T. W. B. Kibble, J. Phys. A9, 1387 (1976); A. Vilenkin, Phys. Rept. 121 (1985) 263

The M3Y-type interaction is similar to the M3Y-Paris and M3Y-Reid interactions.

The algebra of angular momentum operators in QM are very general and apply equally well to orbital as well as spin angular momentum. However, when we are through with the algebra we get 0,1/2,1,3/2,2,5/2,3 ..... etc as the possible ang. mom. values in units of h-bar. We have particles of both types of spin-- scalars, electrons, photons, baryons, gravitons etc. But why don't we have systems with 1/2, 3/2, 5/2 (in h-bar units) of orbital angular momentum?

The gravitational and coulomb potentials are identical, particularly in the weak gravity limit. The Coulomb interaction remains linear in very high field intensities, such as electrons in nuclear fields. However gravitational field interaction in strong gravity limit (but much less than the strength of nuclear field) is highly non linear. The perihelion of orbit of Mercury in the gravitational field of the Sun is an example of non linearity of gravitational interaction. On the other hand no such phenomenon has been observed in this so called electron's orbits around nucleus.

I want to know whether Lorentz symmetry is conserved for all the velocity ranges or not?

Is the Lorentz invariance completely related to Lorentz symmetry; i.e. if Lorentz symmetry conserved then Lorentz invariance is also conserved or there are certain conditions where the Lorentz invariance conserved while Lorentz symmetry is not? what are they if there are such conditions.

There are many physical problems in which the acceleration causes phenomena of interest. For example, the radiation of accelerated charge. This phenomena must be, obviously. of quantum nature, but, the available descriptions start from classic principles. On the other hand, both in Relativity as in quantum physics, the accelerated systems are strongly "hard of to study". The question goes to inquiry about the state of our mathematical tools for the description of accelerated systems in quantum mechanics.

When using propagators and potentials (like the Yukawa one), time is not explicit. Should we use different forms of the propagators and the potentials in a 4d spacetime with time being a 'regular' spacedimension (except for its irreversibility)? Does the incompleteness of particle physics theories come from the fact that time is always treated separately?

The Higgs boson or Higgs particle is an elementary particle initially theorised in 1964,whose discovery was announced at CERN on 4 July 2012. The discovery confirms the existence of the Higgs field, which is pivotal to the Standard Model and other theories within particle physics. It would explain why some fundamental particles have mass when the symmetries controlling their interactions should require them to be massless, and why the weak force has a much shorter range than the electromagnetic force.

The question has following implications

1) What does the term anisotropy mean ?

2) Because universe is homogeneous and isotropic in general

how does one expect anisotropies ?

3) Is it a purely quantum effect ? or is it possible to have

classical explanations of this phenomenon ?

4) Is there a definite pattern in the anisotropy ? If so

how to explain that pattern ?

5) What are theoretical implications for inflationary theories ?

6) Does anisotropies give any indications on the nature

of dark matter. For example is DM cold or warm ?

I am adding a figure; source is

How can I prove that the Gribov problem is related to quark confinement? We know in QCD, perturbation theory can not be applied in infrared region, so does this have anything to do with Gribov copies? If we restrict the integration region in the fundamental modular region, can IR singularity be removed?

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?

The relativistic equations of energy and momentum forbid the possibility that anybody with nonzero rest mass reaches the speed of light because both quantities tend to infinity. In the case of the photon and neutrino, the problem is saved annulling their masses, so that the equations lead to an indetermination, and opens thus the ability to assign the value E = pc for both quantities. But on the other hand, the measurements indicate that neutrinos have nonzero mass. The question is how this theoretical dilemma is resolved.

If I understand correctly, then any matrix can be diagonalized with real and +ve diagonal entries via a bi-unitary transformation. My question is, given a matrix, are the unitary matrices unique?? Is there any common textbook that provides a simple proof of this fact?

The next part of my question involves the quark sector of the Standard Model. In the gauge basis, the "mass matrix" of the quarks is a general complex one. We can then rotate the left and right handed fields separately to go to the mass basis. Now, my problem is that they are called "mass eigenstates" and the masses are called "eigenvalues". But, the Yukawa matrix in the original gauge basis is an arbitrary complex one which does not necessarily have "eigenvalues" in the usual sense of the term. So, is there any way to understand the meaning of the term "mass eigenstate" in this context ?

Proton lifetime is believed to be comparable to the lifetime of the

universe. What is the most recent experimental numbers of

proton lifetime ? What are the unified models which are ruled

out by the latest data of proton lifetime ?

If density perturbations are scale invariant then the dependence should be more like k^0, where k is the wave number. Then why do we define that scale invariant perturbations has spectral index 1. What is the advantage of this choice?

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 ?

We can extract \sqrt{\gamma^0} but not L^\dagger L = \gamma^0, hence the \gamma^0 is a slap-on over the (covariant) operator, not over the wave-function. What does this represent physically? Is there a C (chg. conj.) operator that exists abstractly (answer: no)?

Their masses are powers of 2 in the Planck length basis. Do you have an explanation for that? Calculations must be done in the (x,y,z,t) space.

The spin of particles is a rational number s=p/q, where the numerator p is a non negative integer and the denominator q is equal to two. I want to know if there is an explanation why other values of the integer q are forbidden. What is the origin of the step equal to 1/2 of the Planck constan h?

The Higgs boson interaction gives mass to matters according to standard model. Does that represent the reason of space time curvature in general relativity?

Special relativity (SR) is valid only in Inertial frames. Lorentz transformations (LT) includes both rotations as well as boosts. But rotations gives accelerated frames so how can we connect these SR and LT? In other words, how does this "rotation" give Lorentz Invariance?

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...

For example in a hydrogen atom, the electron is orbitting the nucleus which implies the electron should have some angular momentum, but we say in the ground state (n=1) the angular momentum (l) is zero. Is there any contradiction here..? Can anyone explain this in detail..?

I know that the symmetry breaking event happened when the universe was opaque, nevertheless the balance between the population of photons and other particles might change due to the expected deceleration processes. The corresponding pressures due to such populations might change, so I wonder if there is any chance that there is some pattern in the evolution of the universe that might reveal extra features of the symmetry-breaking event. One could naively expect that it it is not just a change of reference system since the dynamics are different before and after the event. Is there any chance of tracing a contribution to the profile of the spectrum of the cosmic background radiation?

I know there are interesting questions about the problem of propagating such a symmetry breaking event, domain walls, etc.

I wonder also if the negative mass term (quadratic coupling) of the Higgs would give to it some "special dynamics" before the event, and what would be the classical gravitation interactions for such special dynamical objects. I just wonder if there might be some sort of echoes of the symmetry breaking mechanism (beyond the acquisition of rest-mass for some particles).