14,504 research outputs found
Multi-Channel Electron Transfer Reactions: An Analytically Solvable Model
We propose an analytical method for understanding the problem of
multi-channel electron transfer reaction in solution, modeled by a particle
undergoing diffusive motion under the influence of one donor and several
acceptor potentials. The coupling between the donor potential and acceptor
potentials are assumed to be represented by Dirac Delta functions. The
diffusive motion in this paper is represented by the Smoluchowski equation. Our
solution requires the knowledge of the Laplace transform of the Green's
function for the motion in all the uncoupled potentials.Comment: arXiv admin note: substantial text overlap with arXiv:0903.306
Scaling ansatz with texture zeros in linear seesaw
We investigate scaling ansatz with texture zeros within the framework of
linear seesaw mechanism. In this variant of seesaw mechanism a simplified
expression of effective neutrino mass matrix containing two Dirac type
matrices ( and ) and one Majorana type matrix () is
obtained by virtue of neglecting the global symmetry breaking term in
the mass term of the Lagrangian. Along with the charged lepton mass matrix, the
matrix too, is chosen in a diagonal basis whereas a scaling relation
is incorporated in and with different scale factors. Our goal in
this work is to achieve a completely phenomenologically acceptable
generated by combinations of and containing least number of
independent parameters or maximum number of zeros. At the end of the numerical
analysis it is found that number of zeros in any of the constituent Dirac type
matrices ( and ) of cannot be greater than six in order to
meet the phenomenological requirements. The hierarchy obtained here is normal
and also the values of the two parameters sum mass () and
are below the present experimental lower limit.Comment: 18 pages, 10 tables, 1 figure, Accepted for publication in Physics
Letters
Quark Number Susceptibility in Hard Thermal Loop Approximation
We calculate the quark number susceptibility in the deconfined phase of QCD
using the hard thermal loop (HTL) approximation for the quark propagator. This
improved perturbation theory takes into account important medium effects such
as thermal quark masses and Landau damping in the quark-gluon plasma. We
explicitly show that the Landau damping part in the quark propagator for
spacelike quark momenta does not contribute to the quark number susceptibility
due to the quark number conservation. We find that the quark number
susceptibility only due to the collective quark modes deviates from that of
free one around the critical temperature but approaches free results at
infinite temperature limit. The results are in conformity with recent lattice
calculations.Comment: 9 pages including four figures and this version is accepted for
publication in Euro. Phys. J.
Energy gain of heavy quarks by fluctuations in the QGP
The collisional energy gain of a heavy quark due to chromo-electromagnetic
field fluctuations in a quark-gluon plasma is investigated. The field
fluctuations lead to an energy gain of the quark for all temperatures and
velocities. The net effect is a reduction of the collisional energy loss by
15-40% for parameters relevant at RHIC energies.Comment: 6 pages, 4 figures, extended version, accepted for publication in
Phys. Rev.
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