arXiv subjects

Dushmanta Sahu

Publications and source records attributed to Dushmanta Sahu.

38 records · Page 3Linked to original sources

arXiv2020

Multiplicity Dependence of Shear Viscosity, Isothermal Compressibility and Speed of Sound in $pp$ collisions at $\sqrt{s}$ = 7 TeV

In order to understand the detailed dynamics of systems produced in $pp$ collisions, it is essential to know about the Equation of State (EoS) and various thermodynamic properties. In this work, we study the shear viscosity to entropy density ratio, isothermal compressibility and speed of sound of the system by considering a differential freeze-out scenario. We have used a thermodynamically consistent Tsallis non-extensive statistics to have a better explanation for the dynamics of $pp$ collision systems. While the shear viscosity to entropy density ratio provides information about the measure of fluidity of a system formed in high energy collisions, the isothermal compressibility gives a clear idea about the deviation of the system from a perfect fluid. The speed of sound in the system as a function of $\langle dN_{\rm ch}/dη\rangle$ gives us a vivid picture of the dynamics of the system. The results show quite an intuitive perspective on high multiplicity $pp$ collisions and give us a limit of $\langle dN_{\rm ch}/dη\rangle$ $\gtrsim$ (10 - 20), after which a change in the dynamics of the system may be observed.

hep-ph↗

arXiv2020

Role of event multiplicity on hadronic phase lifetime and QCD phase boundary in ultrarelativistic collisions at energies available at the BNL Relativistic Heavy Ion Collider and CERN Large Hadron Collider

Hadronic resonances, having very short lifetime, like $\rm{K}^{*0}$, can act as useful probes to understand and estimate lifetime of hadronic phase in ultra-relativistic proton-proton, p--Pb and heavy-ion collisions. Resonances with relatively longer lifetime, like $ϕ$ meson, can serve as a tool to locate the QGP phase boundary. We estimate a lower limit of hadronic phase lifetime in Cu--Cu and Au--Au collisions at RHIC, and in pp, p--Pb and Pb--Pb collisions at different LHC collision energies. Also, we obtain the effective temperature of $ϕ$ meson using Boltzmann-Gibbs Blast-Wave function, which gives an insight to locate the QGP phase boundary. We observe that the hadronic phase lifetime strongly depends on final state charged-particle multiplicity, whereas the QGP phase and hence the QCD phase boundary shows a very weak multiplicity dependence. This suggests that the hadronisation from a QGP state starts at a similar temperature irrespective of charged-particle multiplicity, collision system and collision energy, while the endurance of hadronic phase is strongly dependent on final state charge-particle multiplicity, system size and collision energy.

hep-ph↗