562 research outputs found
Transport coefficients for multi-component gas of hadrons using Chapman Enskog method
The transport coefficients of a multi-component hadronic gas at zero and
non-zero baryon chemical potential are calculated using the Chapman-Enskog
method. The calculations are done within the framework of an -matrix based
interacting hadron resonance gas model. In this model, the phase-shifts and
cross-sections are calculated using -matrix formalism and where required, by
parameterizing the experimental phase-shifts. Using the energy dependence of
cross-section, we find the temperature dependence of various transport
coefficients such as shear viscosity, bulk viscosity, heat conductivity and
diffusion coefficient. We finally compare our results regarding various
transport coefficients with previous results in the literature
One particle distribution function and shear viscosity in magnetic field: a relaxation time approach
We calculate the correction to the one particle distribution
function in presence of magnetic field and non-zero shear viscosity within the
relaxation time approximation. The correction is found to be
electric charge dependent. Subsequently, we also calculate one longitudinal and
four transverse shear viscous coefficients as a function of dimensionless Hall
parameter in presence of the magnetic field. We find that a proper
linear combination of the shear viscous coefficients calculated in this work
scales with the result obtained from Grad's moment method in
\cite{Denicol:2018rbw}. Calculation of invariant yield of in a simple
Bjorken expansion with cylindrical symmetry shows no noticeable change in
spectra due to the correction for realistic values of the magnetic
field and relaxation time. However, when transverse expansion is taken into
account using a blast wave type flow field we found noticeable change in
spectra and elliptic flow coefficients due to the correction. The
is also found to be very sensitive on the magnitude of magnetic
field. Hence we think it is important to take into account the
correction in more realistic numerical magnetohydrodynamics simulations.Comment: 14 pages, 6 figures, revised version, new section added, new figures
added, published in EPJ
Weibull Distribution and the multiplicity moments in collisions
A higher moment analysis of multiplicity distribution is performed using the
Weibull description of particle production in collisions at
SPS and LHC energies. The calculated normalized moments and factorial moments
of Weibull distribution are compared to the measured data. The calculated
Weibull moments are found to be in good agreement with the measured higher
moments (up to 5 order) reproducing the observed breaking of KNO
scaling in the data. The moments for collisions at = 13 TeV are
also predicted.Comment: 5 pages, 3 figure
Charged participants and their electromagnetic fields in an expanding fluid
We investigate the space-time dependence of electromagnetic fields produced
by charged participants in an expanding fluid. To address this problem, we need
to solve the Maxwell's equations coupled to the hydrodynamics conservation
equation, specifically the relativistic magnetohydrodynamics (RMHD) equations,
since the charged participants move with the flow. To gain analytical insight,
we approximate the problem by solving the equations in a fixed background
Bjorken flow, onto which we solve Maxwell's equations. The dynamical
electromagnetic fields interact with the fluid's kinematic quantities such as
the shear tensor and the expansion scalar, leading to additional non-trivial
coupling. We use mode decomposition of Green's function to solve the resulting
non-linear coupled wave equations. We then use this function to calculate the
electromagnetic field for two test cases: a point source and a transverse
charge distribution. The results show that the resulting magnetic field
vanishes at very early times, grows, and eventually falls at later times.Comment: 13 pages, 5 figures. Minor revisions and a new figure showing domain
of influence adde
- …