Cold Nuclear Matter Effects on J/psi Yields as a Function of Rapidity and Nuclear Geometry in Deuteron-Gold Collisions at sqrt(s_NN) = 200 GeV

TL;DR

This study measures J/psi production in deuteron-gold collisions at 200 GeV to understand cold nuclear matter effects, comparing data with theoretical models including shadowing and gluon saturation.

Contribution

It provides high-precision J/psi yield measurements across a wide rapidity range and evaluates their consistency with different nuclear modification models.

Findings

Forward rapidity data challenge models with linear or exponential density dependence.

Data favor models incorporating complex nuclear effects over simple geometric assumptions.

Results improve understanding of cold nuclear matter effects on quarkonium production.

Abstract

We present measurements of J/psi yields in d+Au collisions at sqrt(s_NN) = 200 GeV recorded by the PHENIX experiment and compare with yields in p+p collisions at the same energy per nucleon-nucleon collision. The measurements cover a large kinematic range in J/psi rapidity (-2.2 < y < 2.4) with high statistical precision and are compared with two theoretical models: one with nuclear shadowing combined with final state breakup and one with coherent gluon saturation effects. To remove model dependent systematic uncertainties we also compare the data to a simple geometric model. We find that calculations where the nuclear modification is linear or exponential in the density weighted longitudinal thickness are difficult to reconcile with the forward rapidity data.