arXiv subjects

H. Goldberg

Publications and source records attributed to H. Goldberg.

4 recordsLinked to original sources

arXiv2014

End of the cosmic neutrino energy spectrum

There may be a high-energy cutoff of neutrino events in IceCube data. In particular, IceCube does not observe either continuum events above 2 PeV, or the Standard Model Glashow-resonance events expected at 6.3 PeV. There are also no higher energy neutrino signatures in the ANITA and Auger experiments. This absence of high-energy neutrino events motivates a fundamental restriction on neutrino energies above a few PeV. We postulate a simple scenario to terminate the neutrino spectrum that is Lorentz-invariance violating, but with a limiting neutrino velocity that is always smaller than the speed of light. If the limiting velocity of the neutrino applies also to its associated charged lepton, then a significant consequence is that the two-body decay modes of the charged pion are forbidden above two times the maximum neutrino energy, while the radiative decay modes are suppressed at higher energies. Such stabilized pions may serve as cosmic ray primaries.

hep-ph↗

arXiv2010

The Hunt for New Physics at the Large Hadron Collider

The Large Hadron Collider presents an unprecedented opportunity to probe the realm of new physics in the TeV region and shed light on some of the core unresolved issues of particle physics. These include the nature of electroweak symmetry breaking, the origin of mass, the possible constituent of cold dark matter, new sources of CP violation needed to explain the baryon excess in the universe, the possible existence of extra gauge groups and extra matter, and importantly the path Nature chooses to resolve the hierarchy problem - is it supersymmetry or extra dimensions. Many models of new physics beyond the standard model contain a hidden sector which can be probed at the LHC. Additionally, the LHC will be a top factory and accurate measurements of the properties of the top and its rare decays will provide a window to new physics. Further, the LHC could shed light on the origin of neutralino masses if the new physics associated with their generation lies in the TeV region. Finally, the LHC is also a laboratory to test the hypothesis of TeV scale strings and D-brane models. An overview of these possibilities is presented in the spirit that it will serve as a companion to the Technical Design Reports (TDRs) by the particle detector groups ATLAS and CMS to facilitate the test of the new theoretical ideas at the LHC. Which of these ideas stands the test of the LHC data will govern the course of particle physics in the subsequent decades.

hep-ph↗

arXiv2008

Phase transition in the fine structure constant

Within the context of mass-varying neutrinos, we construct a cosmological model that has a phase transition in the electromagnetic fine structure constant αat a redshift of 0.5. The model accommodates hints of a time variable αin quasar spectra and the nonobservance of such an effect at very low redshifts. It is consistent with limits from the recombination and primordial nucleosynthesis eras and is free of instabilities.

hep-ph↗

arXiv1992

Exact Nonperturbative Unitary Amplitudes for 1->8 Transitions in a Field Theoretic Model

We present a quantum mechanical model with an infinite number of (discrete) degrees of freedom, which can serve as a laboratory for multiparticle production in a collision. There is a cubic coupling between modes without, however, any problems associated with unstable ground states. The model is amenable to precise numerical calculations of nonperturbative 1->N transition amplitudes. On an ordinary workstation, time and memory limitations effectively restrict N to be $\le\ 8,$ and we present results for this case. We find (1) that there is reasonable period of time for which there is a constant rate for the 1->8 transition; (2) at the end of the linear period, the eight particle amplitude attains a maximum value $\aemax$ which is about $3-4$ orders of magnitude larger than the comparable amplitude for excitation of the $N=8$ state in the anharmonic oscillator; (3) for values of the coupling in the region where the Born approximation fails, the amplitude is much larger than the naive estimates $A_8\simeq \exp{(-1/\g2)}\ $ or $\ \exp{(-8)};$ it is more like $A_8\sim\exp{(-0.20/\g2)}.$

hep-ph↗