118540037
Self-energy of strongly interacting fermions in medium: A holographic approach
Abstract We consider the self-energy of strongly interacting fermions in the medium using gauge/gravity duality of D 4 / D 8 system. We study the mass generation of the thermal and/or dense medium and the collective excitation called plasmino, by considering the spectral function of fermion and its dispersion relation. Our results are very different from those of the hard thermal loop method: for zero density, there is no thermal mass or plasmino in any phase. Plasmino in the deconfined phase is not allowed in D 4 / D 8 setup. In the confined phase, there is a plasmino mode only for a window of density.
118679403
Comments on Baryon Melting in Quark Gluon Plasma with Gluon Condensation
We consider a black hole solution with a non-trivial dilaton from IIB super gravity which is expected to describe a strongly coupled hot gauge plasma with non-vanishing gluon condensation present. We construct a rotating and moving baryon to probe the screening and phases of the plasma. Melting of the baryons in hot plasma in this background had been studied previously, however, we show that baryons melt much lower temperature than has been suggested previously.
118385106
Holographic RG flow and sound modes of sQGP
A bstractWe consider the hydrodynamics of strongly interacting quark gluon plasma in finite temperature and density using the holographic duality of charged black hole in anti DeSitter space. We calculate the transport coefficients at arbitrary energy scale by considering the holographic screen at finite radial position. We first calculate the flow of sound velocity in this method and check the consistence with previous result. Then we calculate diffusion constant of charge and find that Einstein relation between susceptibility, conductivity and diffusion constants will hold at arbitrary slice.
14612850
Holographic melting of heavy baryons in plasma with gluon condensation
We propose a Dirac-Born-Infeld (DBI) D5 vertex brane plus N(c) fundamental strings configuration to describe a baryon probe in strongly coupled gauge theory with gluon condensation at finite temperature via AdS/CFT correspondence. We investigate properties of this configuration in a dilaton deformed AdS(5) x S(5) background, in which IIB string theory is dual to super Yang-Mills theory in a state with a constant self-dual gauge field (F(mn) = F(mn)*) background. We find that for most values of temperature T and gluon condensation parameter q (q = pi(2) ), there always exists a screening length L(s). The relation L(s) similar to 1/T has been checked. We give the q dependence of L(s). We calculate the boost velocity nu(nu = - tanh eta) and angular velocity omega dependence of L(s) for a baryon probe, and obtain L(s) = L(0)* (1-nu(2))(1/4) for large nu and L(s) similar to omega(-1), which are consistent with those dependence relations in the point brane plus strings case, and find that the usual relations have been modified by q. We also calculate the mass of baryon and find T dependence of baryon mass.
119251565
Mixed RG flows and hydrodynamics at finite holographic screen
A bstractWe consider a strongly interacting gauge theory at finite temperature and chemical potential and study renormalization group flows of transport coefficients in the framework of gauge/gravity duality. We first study them using the flow equations and compare the results with hydrodynamic results by calculating the Green functions on the arbitrary slice. Two results match exactly. Transport coefficients at arbitrary scale are obtained by calculating hydrodynamics Green functions. When either momentum or charge vanishes, transport coefficients decouple from each other.
123402029
Interpreting N M2 branes
118710048
Probing the fourth generation Majorana neutrino dark matter
The heavy fourth-generation Majorana neutrino can be stable and contribute to a small fraction of the relic density of dark matter (DM) in the Universe. Because of its strong coupling to the standard model particles, it can be probed by the current direct and indirect DM detection experiments even it is a subdominant component of the whole halo DM. Assuming that it contributes to the same fraction of the local halo DM density as that of the DM relic density in the Universe, we show that the current Xenon100 data constrain the mass of the stable Majorana neutrino to be greater than the mass of the top quark. In the mass range from 200 GeV to a few hundred GeV, the effective spin-independent cross section for the neutrino elastic-scattering off nucleon is insensitive to the neutrino mass and mixing, and is predicted to be similar to 1.5 X 10(-44) cm(2), which can be reached by the direct DM detection experiments soon. In the same mass region the predicted effective spin-dependent cross section for the heavy neutrino scattering off proton is in the range of 2 X 10(-40) cm(2) similar to 2 X 10(-39) cm(2), which is within the reach of the ongoing DM indirect search experiments such as IceCube. We demonstrate such properties of the heavy neutrino DM in a fourth-generation model with the stability of the fourth Majorana neutrino protected by an additional generation-dependent U(1) gauge symmetry.
117860662
New Physics (2HDM) Effects on CP Violation
118334948
Non-Hermitian perturbations to the Fritzsch textures of lepton and quark mass matrices
Abstract We show that non-Hermitian and nearest-neighbor-interacting perturbations to the Fritzsch textures of lepton and quark mass matrices can make both of them fit current experimental data very well. In particular, we obtain θ 23 ≃ 45 ° for the atmospheric neutrino mixing angle and predict θ 13 ≃ 3 ° to 6° for the smallest neutrino mixing angle when the perturbations in the lepton sector are at the 20% level. The same level of perturbations is required in the quark sector, where the Jarlskog invariant of CP violation is about 3.7 × 10 − 5 . In comparison, the strength of leptonic CP violation is possible to reach about 1.5 × 10 − 2 in neutrino oscillations.
204003965
Textures and hierarchies in quark mass matrices with four texture-zeros
A systematic analysis on the phenomenologically allowed textures in Hermitian quark mass matrices with four texture-zeros is presented. The current data allow a full determination of the mass matrix elements, provided that the actual number of the parameters in the matrices is less than or equal to ten. Besides the standard texture with zeros located in (1,1) and (1,3) positions, we find four new type of parallel mass matrices. All of them are found to have similar hierarchical structures: three of the nonzero matrix elements are at the same order of magnitude with a small geometric hierarchy, while the remaining one is relatively much smaller. These textures show a possibility that a realistic quark mass matrix may have an approximate flavor $S(2)_{L}\otimes S(2)_{R}$ symmetry, i.e. a partial flavor democracy. The absolute values of the CP violating phases in the matrix elements are found to be either close to their maximum ($\approx 90^\circ$) or very small ($\leq 10^{\circ}$). We also find twenty-six quasi-parallel and seventeen non-parallel textures allowed by the experimental data.
123787607
The Contribution of Reggeon in charge exchange processes
We discuss in this paper The experimental results on maximum psedo-rapidity $\eta_{max}$ distribution in the charge exchange process $e+p\to e+n+X$ in ZEUS Collaboration at HERA. We calculate the contributions of \regg ($\rho$-Reggeon associated with $\rho$ meson) from regge phenomenology and $\pi^{+}$-exchange from pion cloud model. The results show that neither the \regg-exchange nor the pion cloud model alone can explain the experimental data well, but after considering both these two processes together, by using Monte Carlo simulation, a good agreement between theoretical results and experimental data is found. This means that in discussing the large rapidity gap phenomena in deep inelastic scattering, both of the two processes play substantial role.