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 $m_\nu$ containing two Dirac type matrices ($m_D$ and $m_{DS}$) and one Majorana type matrix ($m_{RS}$) is obtained by virtue of neglecting the global $U(1)_L$ symmetry breaking term in the mass term of the Lagrangian. Along with the charged lepton mass matrix, the matrix $m_{RS}$ too, is chosen in a diagonal basis whereas a scaling relation is incorporated in $m_D$ and $m_{DS}$ with different scale factors. Our goal in this work is to achieve a completely phenomenologically acceptable $m_\nu$ generated by combinations of $m_D$ and $m_{DS}$ 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 ($m_D$ and $m_{DS}$) of $m_\nu$ 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 ($\sum m_i$) and $|m_{\nu_{ee}}|$ 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.