2nd communication: from RERO Explore to swisscovery: Part of RERO's libraries joined the SLSP (Swiss Library Service Platform) network at the beginning of December 2020. See the implications (2nd communication in French / in German) of this change for you as a user.
Title: Characterization of quark gluon plasma as seen through the energy loss of heavy quarks Author:Sheikh, Ashik Ikbal; Ahammed, Zubayer Subject:High Energy Physics - Phenomenology ; Nuclear Theory Description:
The shear viscosity to entropy density ratio ({\eta}/s) of quark gluon plasma produced in ultra- relativistic heavy-ion collisions has been studied from the energy loss of heavy quarks in QGP medium. We have also studied the bulk viscosity to entropy density ratio ({\zeta}/s) and fluidity measure(F) of the medium using the obtained {\eta}/s values. In addition to that, we have estimated the heavy quark bound state potential (V) inside this medium. Our finding of {\eta}/s agrees well with the results obtained by Lattice QCD (LQCD) and functional renormalization group technique.
Identifier:
1803.04123 (ARXIV ID)
Several versions
Effect of the chromo-electromagnetic field fluctuations on heavy quark propagation in a deconfined hadronic medium at energies available at the CERN Large Hadron Collider
Sheikh, Ashik Ikbal, Ahammed, Zubayer, Shukla, Prashant, Mustafa, Munshi G.
Physical Review C, 21 September 2018, Vol.98(3)
[Peer Reviewed Journal]
Title: Heavy flavour Langevin diffusion with the chromo-electromagnetic field fluctuations in the quark-gluon plasma Author:Sheikh, Ashik Ikbal; Ahammed, Zubayer Subject:High Energy Physics - Phenomenology ; Nuclear Theory Description:
The chromo-electromagnetic field is produced due to the motion of partons in a quark-gluon plasma created by relativistic heavy-ion collisions. The fluctuations in the produced chromo-electromagnetic field are important, since they cause heavy quarks to gain energy in the low velocity limit. We study the effect of such fluctuations on heavy quark diffusion in quark-gluon plasma within the framework of Langevin dynamics under the background matter described by the ($3+1$)-dimensional relativistic viscous hydrodynamics. Theoretical calculations of the nuclear modification factor ($R_{AA}$) of heavy mesons ($D$ and $B$ mesons), with the effect of these fluctuations, are compared with experimental measurements in $Au-Au$ collisions at $\sqrt{s_{NN}} = 200$ GeV by the STAR experiment at the BNL Relativistic Heavy Ion Collider (RHIC) and $Pb-Pb$ collisions at $\sqrt{s_{NN}} = 2.76$ and $5.02$ TeV by the ALICE and CMS experiments at the CERN Large Hadron Collider (LHC). We find a significant effect of these fluctuations in describing the the measured $R_{AA}$ of $D$ and $B$ mesons in both RHIC and LHC energies.
Identifier:
1902.02477 (ARXIV ID)
Title: Impact of the chromo-electromagnetic field fluctuations on transport coefficients of heavy quarks and shear viscosity to entropy density ratio of quark-gluon plasma Author:Sheikh, Ashik Ikbal; Ahammed, Zubayer Subject:High Energy Physics - Phenomenology ; Nuclear Theory Description:
The chromo-electromagnetic field fluctuations in the quark-gluon plasma (QGP) play an important role as these field fluctuations result energy gain of heavy quarks. We consider these fluctuations and evaluate the transport coefficients, e.g., drag and diffusion coefficients of charm quarks and shear viscosity to entropy density ratio ($\eta/s$) of the QGP. We find a significant effect of such fluctuations on the transport coefficients. These fluctuations cause a reduction of the drag and diffusion coefficients. We also observe that the shear viscosity to entropy density ratio of the QGP is closer to the value obtained in Lattice QCD (LQCD) and functional renormalization group calculations when the effects of such fluctuations are included. Comment: Accepted in Nucl. Phys. A
Identifier:
1903.10690 (ARXIV ID)
Title: The role of the stochastic color field fluctuations on $J/\psi$ suppression in ultra-relativistic heavy-ion collisions Author:Sheikh, Ashik Ikbal; Ahammed, Zubayer; Mustafa, M. G. Subject:High Energy Physics - Phenomenology ; Nuclear Theory Description:
We consider the effect of the stochastic color field fluctuations in addition to the collisional as well as the radiative energy losses in the propagation of charm quarks in the hot and dense deconfined medium of quarks and gluons created in ultra-relativistic heavy-ion collisions. These fluctuations lead to energy gain of the propagating charm quarks. We construct and solve Langevin transport equations for charm quarks under the evolving background matter described by the ($3+1$)-D relativistic viscous hydrodynamics. Considering the energy gain of charm quarks, the nuclear modification factor $R_{AA}$ of $J/\psi$ is calculated. Interestingly, the experimental measurements for $J/\psi$ suppression in $Au-Au$ collisions at $\sqrt{s_{NN}} = 200$ GeV by PHENIX Collaboration and $Pb-Pb$ collisions at $\sqrt{s_{NN}} = 2.76$ TeV by ALICE and CMS Collaborations, can be nicely described with the effect of these field fluctuations without invoking the regeneration phenomena.
Identifier:
1902.06989 (ARXIV ID)
Several versions
Study of medium modified jet shape observables in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV using EPOS and JEWEL event generators