All posts under category "HEP-PH / Hep-Ph"
The superluminal propagation of neutrinos observed by OPERA collaboration can be interpreted as neutrinos traveling in a pseudoscalar potential which may be generated by a medium. The OPERA differential arrival time data set a constraint on the form of the pseudoscalar potential.
Topological vector currents have gained interest recently with their possible verification at RHIC through the Charge Separation Effect and the Chiral Magnetic Effect. Much work has been done in understanding the role of topological vector currents in astrophysics, specifically in the interiors of n
We show that the energy spectra from dark matter (DM) annihilation into $f^+f^-gamma$ (where $f$ is a light fermion) via chirality preserving interactions are identical in 3 scenarios: (a) DM is a Majorana fermion and the particle exchanged is a scalar, (b) DM is a Majorana fermion and the particle
We examine the ability for the Large Area Telescope (LAT) to constrain Minimal Supersymmetric Standard Model (MSSM) dark matter through a combined analysis of Milky Way dwarf spheroidal galaxies. We examine the Lightest Supersymmetric Particles (LSPs) for a set of ~71k experimentally valid supersymm
This paper reports a new phenomenological analysis of the neutrino burst detected from SN 1987 A, and it reveals the presence of two mass eigenstates. The heavier mass eigenstate has $m_H=21.4 pm 1.2 eV/c^2$, while the lighter one has $m_L=4.0 pm0.5 eV/c^2 $. It is not the first paper to make such a
If a Higgs field is conformally coupled to gravity, then it can give rise to the scale invariant density perturbations. We make use of this result in a realistic inert Higgs doublet model, where we have a pair of Higgs doublets conformally coupled to the gravity in the early universe. The perturbati
High-energy neutrinos, arising from decays of mesons produced through the collisions of cosmic ray particles with air nuclei, form the background in the astrophysical neutrino detection problem. An ambiguity in high-energy behavior of pion and especially kaon production cross sections for nucleon-nu
Lorentz invariance is such an important principle of fundamental physics that it should constantly be subjected to experimental scrutiny as well as theoretical questioning. Distant astrophysical sources of energetic photons with rapid time variations, such as active galactic nuclei (AGNs) and gamma-
The structure of a magnetized quark-hybrid stars (QHS) is modeled using a standard relativistic mean-field equation of state (EoS) for the description of hadronic matter. For quark matter we consider a bag model EoS which is modified perturbatively to account for the presence of a uniform magnetic f
The QCDMAPT program package facilitates computations in the framework of dispersive approach to Quantum Chromodynamics. The QCDMAPT_F version of this package enables one to perform such computations with Fortran, whereas the previous version was developed for use with Maple system. The QCDMAPT_F pac
We search for extended regions of radio emission not associated with Active Galactic Nuclei, known as 'relics', 'halos' and 'mini halo's, in a sample of 70 Abell clusters for which we have radio, optical and X-ray data. AGN can produce particle bubbles of non-thermal emission, which can restrict cos
Interpretation of measurements of the muon charge ratio in the TeV range depends on the spectra of protons and neutrons in the primary cosmic radiation and on the inclusive cross sections for production of $pi^pm$ and $K^pm$ in the atmosphere. Recent measurements of the spectra of cosmic-ray nuclei
Two simple exercises are solved, which educators can use to awake interest of their students in subtleties of the CERN Neutrino beam to Grand Sasso (CNGS) experiment. The first one is about the statistical error of the average departure time of neutrinos from CERN. The second one about a hypothetica
In this article I review model-independent procedures for extracting properties of Weakly Interacting Massive Particles (WIMPs) from direct Dark Matter detection experiments. Neither prior knowledge about the velocity distribution function of halo Dark Matter particles nor about their mass or cross
Recent observational results for the masses and radii of some neutron stars are in contrast with typical observations and theoretical predictions for 'normal' neutron stars. We propose that their unusual properties can be interpreted as the signature of a dark matter core inside them. This interpret
We analytically compute the effects that a mass variation rate dot M/M of a pulsar may have on the changes Deltatau in the times of arrival of its pulses due to test particle companions, and on their orbital dynamics. We apply our results to the planetary system of the PSR B1257+12 pulsar, located i
The Fermi LAT collaboration has recently presented constraints on the gamma-ray signal from annihilating dark matter using separate analyses of a number of dwarf spheroidal galaxies. Since the expected annihilation signal has the same physical properties regardless of the target (except for a normal
The bremsstrahlung cross section for relativistic electrons in a crystal is split into the sum of coherent and incoherent parts (the last is due to a thermal motion of atoms in the crystal). Although the spectrum of incoherent radiation in crystal is similar to one in amorphous medium, the incoheren
It has recently been pointed out that particles falling freely from rest at infinity outside a Kerr black hole can in principle collide with arbitrarily high center of mass energy in the limiting case of maximal black hole spin. Here we aim to elucidate the mechanism for this fascinating result, and
In a recent analysis it was found that the local (z=0) rate at which gamma-ray bursts (GRBs) produce energy in 1 MeV photons, Q_GRB(z=0), is 300 times lower than the local energy production rate in ultra-high energy cosmic-rays. This may appear to be in contradiction with earlier results, according
We point out that if quantum field renormalization is taken into account, and the counterterms are evaluated at the Hubble-radius crossing time or few e-foldings after it, the predictions of slow-roll inflation for both the scalar and tensorial power spectrum change significantly. This leads to a ch
The effects of anomalies in high density QCD are striking. We consider a direct application of one of these effects, namely topological currents, on the physics of neutron stars. All the elements required for topological currents are present in neutron stars: degenerate matter, large magnetic fields
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