Collisional Energy Loss of Fast Charged Particles in Relativistic Plasmas

Following an argument by Kirzhnits we rederive an exact expression for the energy loss of a fast charged particle in a relativistic plasma using the quantum field theoretical language. We compare this result to perturbative calculations of the collisional energy loss of an energetic electron or muon in an electron-positron plasma and of an energetic parton in the quark-gluon plasma.Comment: 9 pages, LATEX, 2 PostScript figure

Decay of a Yukawa fermion at finite temperature and applications to leptogenesis

We calculate the decay rate of a Yukawa fermion in a thermal bath using finite temperature cutting rules and effective Green's functions according to the hard thermal loop resummation technique. We apply this result to the decay of a heavy Majorana neutrino in leptogenesis. Compared to the usual approach where thermal masses are inserted into the kinematics of final states, we find that deviations arise through two different leptonic dispersion relations. The decay rate differs from the usual approach by more than one order of magnitude in the temperature range which is interesting for the weak washout regime. We discuss how to arrive at consistent finite temperature treatments of leptogenesis.Comment: 16 pages, 5 figure

The Judiciary in Virginia: Changes and Challenges in Virginia: One Trial Judge\u27s Perspective

With the convening of the 2014 Virginia General Assembly, members of the Senate and House received the anticipated 2013 Judicial Workload Assessment Report-a weighted case load study produced by the National Center for State Courts and commissioned by the legislature during its 2012 session. The purpose of the study was to help guide both the future selection of judges and the allocation of the political boundaries to be served by those judges. The results of the weighted caseload study as contained in the 2013 Report would validate many of those concerns expressed earlier by the 2011 Judicial Boundary Realignment Committee appointed by the Supreme Court. In addition, the 2013 Report would include a myriad of comments and concerns voiced by legislators, lawyers, judges, court personnel, law enforcement, and the general public concerning judicial need in the Commonwealth. This article will seek to describe the results of the 2013 Virginia Judicial Workload Assessment Report within the context of an evolving dialogue in the Virginia General Assembly concerning judicial resources. It is a dialogue that has taken place since the beginning of the Commonwealth and became a focal point during the General Assembly\u27s 2014 session. This dialogue intensified when House Bill 1990 and Senate Bill 1240 were introduced during the General Assembly\u27s 2011 session

The Judiciary in Virginia: Changes and Challenges in Virginia: One Trial Judge\u27s Perspective

With the convening of the 2014 Virginia General Assembly, members of the Senate and House received the anticipated 2013 Judicial Workload Assessment Report-a weighted case load study produced by the National Center for State Courts and commissioned by the legislature during its 2012 session. The purpose of the study was to help guide both the future selection of judges and the allocation of the political boundaries to be served by those judges. The results of the weighted caseload study as contained in the 2013 Report would validate many of those concerns expressed earlier by the 2011 Judicial Boundary Realignment Committee appointed by the Supreme Court. In addition, the 2013 Report would include a myriad of comments and concerns voiced by legislators, lawyers, judges, court personnel, law enforcement, and the general public concerning judicial need in the Commonwealth. This article will seek to describe the results of the 2013 Virginia Judicial Workload Assessment Report within the context of an evolving dialogue in the Virginia General Assembly concerning judicial resources. It is a dialogue that has taken place since the beginning of the Commonwealth and became a focal point during the General Assembly\u27s 2014 session. This dialogue intensified when House Bill 1990 and Senate Bill 1240 were introduced during the General Assembly\u27s 2011 session

Photon-Photon Interaction in a Photon Gas

Using the effective Lagrangian for the low energy photon-photon interaction the lowest order photon self energy at finite temperature and in non-equilibrium is calculated within the real time formalism. The Debye mass, the dispersion relation, the dielectric tensor, and the velocity of light following from the photon self energy are discussed. As an application we consider the interaction of photons with the cosmic microwave background radiation.Comment: REVTEX, 7 pages, 1 PostSrcipt figur

Conserved Density Fluctuation and Temporal Correlation Function in HTL Perturbation Theory

Considering recently developed Hard Thermal Loop perturbation theory that takes into account the effect of the variation of the external field through the fluctuations of a conserved quantity we calculate the temporal component of the Euclidian correlation function in the vector channel. The results are found to be in good agreement with the very recent results obtained within the quenched approximation of QCD and small values of the quark mass ($\sim 0.1T$) on improved lattices of size $128^3\times N_\tau$ at ($N_\tau=40, \ T=1.2T_C$), ($N_\tau=48, \ T=1.45T_C$), and ($N_\tau=16, \ T=2.98T_C$), where $N_\tau$ is the temporal extent of the lattice. This suggests that the results from lattice QCD and Hard Thermal Loop perturbation theory are in close proximity for a quantity associated with the conserved density fluctuation.Comment: 16 pages, 4 figures; One para added in introduction, Fig 1 modified; Accepted in Phys. Rev.

Interference phenomena in the JP=1/2−J^P=1/2^--wave in η\eta photoproduction

The recent precise experimental results for the photoproduction of $\eta$-mesons off the neutron measured with the Crystal Ball/TAPS calorimeter at the MAMI accelerator have been investigated in detail in the framework of the Bonn-Gatchina coupled channel model. The main result is that the narrow structure observed in the excitation function of $\gamma n \rightarrow n\eta$ can be reproduced fully with a particular interference pattern in the $J^P=1/2^-$ partial wave. Introduction of the narrow resonance $N(1685)$ with the properties reported in earlier publications deteriorates the quality of the fit.Comment: 10 pages, 13 figures, accepted for publication in EPJ

Flavor ordering of elliptic flows at high transverse momentum

Based on the quark coalescence model for the parton-to-hadron phase transition in ultra-relativistic heavy ion collisions, we relate the elliptic flow ($v_2$) of high \pt hadrons to that of high \pt quarks. For high \pt hadrons produced from an isospin symmetric and quark-antiquark symmetric partonic matter, magnitudes of their elliptic flows follow a flavor ordering as $(v_{2,\pi}=v_{2,N}) > (v_{2,\Lambda}=v_{2,\Sigma}) > v_{2,K} > v_{2,\Xi} > (v_{2,\phi}=v_{2,\Omega})$ if strange quarks have a smaller elliptic flow than light quarks. The elliptic flows of high \pt hadrons further follow a simple quark counting rule if strange quarks and light quarks have same high \pt spectrum and coalescence probability.Comment: 4 pages, 1 figure, revte