arXiv subjects

Ashish Pandav

Publications and source records attributed to Ashish Pandav.

3 recordsLinked to original sources

arXiv2026

Recent STAR Measurements from the RHIC Beam Energy Scan II

We present selected recent results from the second phase of the Beam Energy Scan program (BES-II) at RHIC, based on high-statistics data collected by the STAR experiment in collider and fixed-target modes, covering $\sqrt{s_{NN}}=3.0$--$27$~GeV. New results from isobar (Ru+Ru, Zr+Zr) collisions at $\sqrt{s_{NN}} = 200$~GeV are also presented. The presented results span bulk properties and strangeness production, femtoscopy, collectivity and hyperon polarization, and fluctuation observables sensitive to the QCD phase structure. Future prospects with newly recorded fixed-target datasets are also briefly outlined.

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arXiv2020

Measurement of cumulants of conserved charge multiplicity distributions in Au+Au collisions from the STAR experiment

We report the collision-centrality dependence of cumulants of event-by-event net-proton, net-charge and net-kaon distributions in Au+Au collisions for center-of-mass energy $\sqrt{s_{NN}}$ = 54.4 GeV from the STAR experiment. Strong collision-centrality dependence is observed for cumulants ($C_{n}, n$ $\leq$ 4) of the net-particle distributions. The cumulant ratios $C_{3}/C_{2}$, $C_{4}/C_{2}$ and $C_{6}/C_{2}$ exhibit a weak collision-centrality dependence. The $C_{6}/C_{2}$ of net-proton and net-charge distributions for most central gold nuclei collisions at $\sqrt{s_{NN}}$ = 54.4 GeV show positive sign while they remain negative at 200 GeV for the same collision system. To understand effects of acceptance and baryon number conservation, the measurements are compared to expectations from the UrQMD and HIJING models calculated within the STAR detector acceptance.

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arXiv2018

Effect of limited statistics on higher order cumulants measurement in heavy-ion collision experiments

We have studied the effect of limited statistics of data on measurement of the different order of cumulants of net-proton distribution assuming that the proton and antiproton distributions follow Possionian and Binomial distributions with initial parameters determined from experimental results for two top center of mass energies ($\sqrt{s_{\mathrm{NN}}}=200$ and $62.4$ GeV) in most central ($0-5$%) Au$+$Au collisions at Relativistic Heavy Ion Collider (RHIC). In this simulation, we observe that the central values for higher order cumulants have a strong dependence on event sample size and due to statistical randomness the central values of higher order cumulants could become negative. We also present a study on the determination of the statistical error on cumulants using delta theorem, bootstrap and sub-group methods and verified their suitability by employing a Monte Carlo procedure. Based on our study we find that the bootstrap method provides a robust way for statistical error estimation on high order cumulants. We also present the exclusion limits on the minimum event statistics needed for determination of cumulants if the signal strength (phase transition or critical point) is at a level of $5$% and $10$% above the statistical level. This study will help the experiments to arrive at the minimum required event statistics and choice of proper method for statistical error estimation for high order cumulant measurements.

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