Conserved charge fluctuations using the $D$-measure in heavy-ion collisions

Abstract

We study the net-charge fluctuations, $D$-measure variable, in high energy heavy-ion collisions in heavy-ion jet interaction generator (HIJING), ultrarelativistic quantum molecular dynamics (UrQMD) and hadron resonance gas (HRG) models for various center-of-mass energies (\sqsn). The effect of kinematic acceptance and resonance decay, in the pseudorapidity acceptance interval ($Δη$) and lower transverse momentum ($p_{T}^{min}$) threshold, on fluctuation measures are discussed. A strong dependence of $D$ with the $Δη$ in HIJING and UrQMD models is observed as opposed to results obtained from the HRG model. The dissipation of fluctuation signal is estimated by fitting the $D$-measure as a function of the $Δη$. An extrapolated function for higher $Δη$ values at lower \sqsn is different from the results obtained from models. Particle species dependence of $D$ and the effect of the $p_T^{min}$ selection threshold are discussed in HIJING and HRG models. The comparison of $D$, at midrapidity, of net-charge fluctuations at various \sqsn obtained from the models with the data from the ALICE experiment is discussed. The results from the present work as a function of $Δη$ and \sqsn will provide a baseline for comparison to experimental measurements.

9 pages, 8 figures. Published in Physical Review C