Longitudinal scaling property of the charge balance function in Au + Au collisions at 200 GeV

TL;DR

This study measures the charge balance function in Au + Au collisions at 200 GeV, revealing its boost-invariance and a decreasing width with increasing transverse momentum, indicating a longitudinal scaling property.

Contribution

It demonstrates the longitudinal scaling property of the charge balance function across pseudorapidity and transverse momentum ranges in heavy-ion collisions.

Findings

Balance function is boost-invariant within pseudorapidity coverage.

Scaled balance function width is independent of pseudorapidity window size.

Balance function width decreases monotonically with increasing transverse momentum.

Abstract

We present measurements of the charge balance function, from the charged particles, for diverse pseudorapidity and transverse momentum ranges in Au + Au collisions at 200 GeV using the STAR detector at RHIC. We observe that the balance function is boost-invariant within the pseudorapidity coverage [-1.3, 1.3]. The balance function properly scaled by the width of the observed pseudorapidity window does not depend on the position or size of the pseudorapidity window. This scaling property also holds for particles in different transverse momentum ranges. In addition, we find that the width of the balance function decreases monotonically with increasing transverse momentum for all centrality classes.