178,015 research outputs found
Jet conversions in a quark-gluon plasma
Quark and gluon jets traversing through a quark-gluon plasma not only lose
their energies but also can undergo flavor conversions. The conversion rates
via the elastic and the inelastic scatterings are evaluated in the lowest order in QCD.
Including both jet energy loss and conversions in the expanding quark-gluon
plasma produced in relativistic heavy ion collisions, we have found a net
conversion of quark to gluon jets. This reduces the difference between the
nuclear modification factors for quark and gluon jets in central heavy ion
collisions and thus enhances the and ratios at high
transverse momentum. However, a much larger net quark to gluon jet conversion
rate than the one given by the lowest-order QCD is needed to account for the
observed similar ratios in central Au+Au and p+p collisions at same energy.
Implications of our results are discussed.Comment: version to appear in PR
Remark on approximation in the calculation of the primordial spectrum generated during inflation
We re-examine approximations in the analytical calculation of the primordial
spectrum of cosmological perturbation produced during inflation. Taking two
inflation models (chaotic inflation and natural inflation) as examples, we
numerically verify the accuracy of these approximations.Comment: 10 pages, 6 figures, to appear in PR
Non-Extensive Quantum Statistics with Particle - Hole Symmetry
Based on Tsallis entropy and the corresponding deformed exponential function,
generalized distribution functions for bosons and fermions have been used since
a while. However, aiming at a non-extensive quantum statistics further
requirements arise from the symmetric handling of particles and holes
(excitations above and below the Fermi level). Naive replacements of the
exponential function or cut and paste solutions fail to satisfy this symmetry
and to be smooth at the Fermi level at the same time. We solve this problem by
a general ansatz dividing the deformed exponential to odd and even terms and
demonstrate that how earlier suggestions, like the kappa- and q-exponential
behave in this respect
Possible and Molecular states in a chiral quark model
We perform a systematic study of the bound state problem of and
systems by using effective interaction in our chiral quark model.
Our results show that both the interactions of and states
are attractive, which consequently result in
and bound states.Comment: arXiv admin note: substantial text overlap with arXiv:1204.395
Magnon Mediated Electric Current Drag Across a Ferromagnetic Insulator Layer
In a semiconductor hererostructure, the Coulomb interaction is responsible
for the electric current drag between two 2D electron gases across an electron
impenetrable insulator. For two metallic layers separated by a ferromagnetic
insulator (FI) layer, the electric current drag can be mediated by a
nonequilibrium magnon current of the FI. We determine the drag current by using
the semiclassical Boltzmann approach with proper boundary conditions of
electrons and magnons at the metal-FI interface.Comment: 13 pages, 2 figures: to appear in PR
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