Study of dynamical charge fluctuations in the hadronic medium

The dynamical charge fluctuations have been studied in ultra-relativistic heavy-ion collisions by using hadronic model simulations, such as UrQMD and HIJING. The evolution of fluctuations has been calculated at different time steps during the collision as well as different observation window in pseudorapidity (\DelEta). The final state effects on the fluctuations have been investigated by varying $\bigtriangleup\eta$~ and the time steps with the aim of obtaining an optimum observation window for capturing maximum fluctuations. It is found that $\bigtriangleup\eta$~ between 2.0 and 3.5 gives the best coverage for the fluctuations studies. The results of these model calculations for Au+Au collisions at $\sqrt{s_{\rm NN}}$~=~7.7 to 200~GeV and for Pb+Pb collisions at 2.76 TeV are presented and compared with available experimental data from the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC).Comment: 6 pages, 4 Figure

Cumulants of net-strangeness multiplicity distributions at energies available at the BNL Relativistic Heavy Ion Collider

The higher-order cumulants of net-proton number, net-charge, and net-strangeness multiplicity distributions are widely studied to search for the quantum-chromodynamics critical point and extract the chemical freeze-out parameters in heavy-ion collisions. In this context, the event-by-event fluctuations of the net-strangeness multiplicity distributions play important roles in extracting the chemical freeze-out parameter in the strangeness sector. Due to having difficulties in detecting all strange hadrons event by event, the kaon ($K$) and lambda ($\Lambda$) particles serve as a proxy for the strangeness-related observables in heavy-ion collisions. We have studied the net-$K$, net-$\Lambda$, and net-($K$ + $\Lambda$) multiplicity distributions and calculated their different order of cumulants using the ultrarelativistic quantum molecular dynamics model and hadron resonance gas calculation. To adequately account for the net-strangeness cumulants, it has been found that the inclusion of resonance decay contributions in $K$ and $\Lambda$ is necessary.Comment: The title has been modified. Updated following the published versio