J/psi Production in sqrt (s_NN)= 200 GeV Cu+Cu Collisions

TL;DR

This paper reports measurements of J/psi production in Cu+Cu collisions at 200 GeV, providing detailed data across rapidity, transverse momentum, and centrality to help distinguish cold from hot nuclear matter effects.

Contribution

It presents the first detailed measurement of J/psi yields in Cu+Cu collisions at 200 GeV, with improved precision over previous Au+Au data, aiding in understanding nuclear matter effects.

Findings

J/psi yields vary with rapidity, transverse momentum, and centrality.

Data constrains cold and hot nuclear matter effects.

Provides benchmark data for small to intermediate collision systems.

Abstract

Yields for J/psi production in Cu+Cu collisions at sqrt (s_NN)= 200 GeV have been measured by the PHENIX experiment over the rapidity range |y| < 2.2 at transverse momenta from 0 to beyond 5 GeV/c. The invariant yield is obtained as a function of rapidity, transverse momentum and collision centrality, and compared with results in p+p and Au+Au collisions at the same energy. The Cu+Cu data provide greatly improved precision over existing Au+Au data for J/psi production in collisions with small to intermediate numbers of participants, providing a key constraint that is needed for disentangling cold and hot nuclear matter effects.