Correlations of Feed-down Hadrons in a Thermal Model

TL;DR

This study investigates how strong decays influence fluctuations of net quantum numbers and balance functions in a thermal hadron gas, highlighting their significant impact on experimental measurements related to QCD phase transition signals.

Contribution

It provides a comprehensive analysis of feed-down effects on particle yields and correlations using a thermal model with detailed decay channels, relevant for QCD critical point searches.

Findings

Decays significantly affect stable particle yields.

Feed-down impacts net quantum number fluctuations.

Results are relevant for RHIC and LHC measurements.

Abstract

We examine the potential impact of strong decays on the magnitude of fluctuations of net quantum numbers and integrals of balance functions based on a thermal hadron gas model. The calculations are based on a comprehensive list of known hadrons with masses up to 2.5 GeV/$c^2$ and include all decays of these hadrons with known branching fractions. The calculations are performed at vanishing baryo-chemical potential for temperatures between 140 and 200 MeV. We show that the decays feed-down substantially impact the single yield of measurable ``stable particles" as well as those of correlated densities of these species. Decays can then potentially have large and non-trivial impacts on measurements of net quantum number cumulants and balance functions. These observations are particularly important in the context of the search for the QCD critical point at the RHIC Beam Energy Scan as well as efforts to determine chemical susceptibilities near the phase transition at RHIC or LHC energies. Results obtained in this work also shed light on the importance of feed-down in measurements of balance functions in elementary p-p and nucleus-nucleus collisions.