Long-range pseudorapidity dihadron correlations in $d$+Au collisions at $\sqrt{s_{\rm NN}}=200$ GeV

TL;DR

This study investigates long-range dihadron correlations in deuteron-gold collisions at 200 GeV, revealing a near-side correlation at large pseudorapidity differences and analyzing the Fourier components' dependence on pseudorapidity and multiplicity.

Contribution

It provides the first detailed measurement of long-range pseudorapidity dihadron correlations in $d$+Au collisions, highlighting the scaling behavior and Fourier coefficient dependencies.

Findings

Finite near-side correlated yield at large $igtriangleup\,eta$

Fourier coefficient $V_1$ inversely proportional to multiplicity

Fourier coefficient $V_2$ independent of multiplicity and similar in both directions

Abstract

Dihadron angular correlations in $d$+Au collisions at $\sqrt{s_{\rm NN}}=200$ GeV are reported as a function of the measured zero-degree calorimeter neutral energy and the forward charged hadron multiplicity in the Au-beam direction. A finite correlated yield is observed at large relative pseudorapidity ($\Delta\eta$) on the near side (i.e. relative azimuth $\Delta\phi\sim0$). This correlated yield as a function of $\Delta\eta$ appears to scale with the dominant, primarily jet-related, away-side ($\Delta\phi\sim\pi$) yield. The Fourier coefficients of the $\Delta\phi$ correlation, $V_{n}=\langle\cos n\Delta\phi\rangle$, have a strong $\Delta\eta$ dependence. In addition, it is found that $V_{1}$ is approximately inversely proportional to the mid-rapidity event multiplicity, while $V_{2}$ is independent of it with similar magnitude in the forward ($d$-going) and backward (Au-going) directions.