arXiv subjects

Sukanya Mitra

Publications and source records attributed to Sukanya Mitra.

42 records · Page 3Linked to original sources

arXiv2013

Effect of in-medium spectral density of $D$ and $D^*$ mesons on the $J/ψ$ dissociation in hadronic matter

The one-loop self-energy of the $D$ and $D^*$ mesons in a hot hadronic medium is evaluated using the real time formalism of thermal field theory. The interaction of the heavy open-charm mesons with the thermalized constituents $(π,K,η)$ of the hadronic matter is treated in the covariant formalism of heavy meson chiral perturbation theory. The imaginary parts are extracted from the discontinuities of the self-energy function across the unitary and the Landau cuts. The non-zero contribution from the latter to the spectral density of $D$ and $D^*$ mesons opens a number of subthreshold decay channels of the $J/ψ$ leading to a significant increase in the dissociation width in hadronic matter.

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arXiv2013

Medium effects on the viscosities of a pion gas

The bulk and shear viscosities of a pion gas is obtained by solving the relativistic transport equation in the Chapman-Enskog approximation. In-medium effects are introduced in the $ππ$ cross-section through one-loop self-energies in the propagator of the exchanged $ρ$ and $σ$ mesons. The effect of early chemical freeze-out in heavy ion collisions is implemented through a temperature dependent pion chemical potential. These are found to affect the temperature dependence of the bulk and shear viscosities significantly.

hep-ph↗

arXiv2013

Characterizing quark gluon plasma by thermal photons and lepton pairs

The photon spectra measured by the ALICE collaboration in Pb+Pb collisions at Large Hadron Collider (LHC) energies has been analyzed with a view of extracting the properties of thermal system formed in these collisions. The results of the analysis are compared with the previously studied spectra measured at Super Proton Synchrotron (SPS) and Relativistic Heavy Ion Collider (RHIC) energies. The thermal dilepton spectra from the Pb+Pb collision at LHC energy has been predicted for the initial conditions constrained by the thermal photon spectra at the same collision conditions. The slope of the photon has been used to estimate the rise in the effective degeneracy with the charged particle multiplicity of the system. The slopes of the lepton pair spectra for different invariant mass windows have been used to conjecture the average radial flow velocity of the high temperature phase.

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arXiv2012

Effect of spectral modification of $ρ$ on shear viscosity of a pion gas

We evaluate the shear viscosity of a pion gas in the relativistic kinetic theory approach. The in-medium propagator of the $ρ$ meson at finite temperature is used to evaluate the $π-π$ scattering amplitude in the medium. The real and imaginary parts of the self-energy calculated from one-loop diagrams are seen to have noticeable effects on the scattering cross-section. The consequences on temperature dependence of the shear viscosity evaluated in the Chapman-Enskog and relaxation time approximations are studied.

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arXiv2012

Effect of running coupling on photon emission from quark gluon plasma

We discuss the role of running coupling on the thermal photon yield from quark gluon plasma. It is shown that the photon production rate from the partonic phase is considerably enhanced when running coupling is considered with respect to a fixed value. However, we show by explicit evaluation that although this difference survives the space-time evolution the experimental data cannot distinguish between the two once the hard contribution, which is an essential component of photon production mechanism, is added.

hep-ph↗

arXiv2011

Thermal radiation from an expanding viscous medium

The effects of viscosity on the space time evolution of QGP produced in nuclear collisions at RHIC energies have been studied. The entropy generated due to the viscous motion of the fluid has been taken into account in constraining the initial temperature by the final multiplicity (measured at the freeze-out point). The viscous effects on the photon spectra has been introduced consistently through the evolution dynamics and phase space factors of the particles participating in the production process. We notice a stronger effect on the photon spectra originating from QGP than hadronic matter. A detectable shift is observed in the space-time integrated p_T distribution of photons due to dissipative effects.

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