Pileup Correction on Higher-order Cumulants with Unfolding Approach

TL;DR

This paper investigates the impact of pileup events on higher-order cumulants in heavy-ion collisions and introduces a model-independent unfolding method to correct for pileup effects, enhancing measurement accuracy.

Contribution

It proposes a novel, model-independent unfolding approach for pileup correction in higher-order cumulant measurements, overcoming limitations of previous methods.

Findings

Pileup significantly affects higher-order cumulant measurements.

The proposed unfolding method effectively corrects pileup effects.

Traditional correction methods fail when parameters are derived from Glauber fits.

Abstract

Higher-order cumulants of conserved charge distributions are sensitive observables to probe the critical fluctuations near QCD critical point in heavy-ion collisions. Due to high interaction rate, pileup event can be one of the major sources of background in the measurements of higher-order cumulants. In this paper, we studied the effects of pileup events on higher-order cumulants of proton multiplicity distributions using UrQMD model. It is found that the proposed pileup correction fails if the correction parameters are determined by the Glauber fitting of charged particle multiplicities, which is usually done in the real heavy-ion experiment. To address this, we propose a model independent unfolding approach to determine the parameters in the pileup correction. This approach can be applied in the pileup correction for the future measurement of higher-order cumulants in heavy-ion collision experiment.