J/\psi suppression at forward rapidity as a potential probe for QGP formation in colour screening scenario

TL;DR

This paper extends a formalism for J/psi suppression to include full rapidity, transverse momentum, and centrality dependence, comparing predictions with experimental data to probe QGP formation via color screening.

Contribution

It introduces a more general model for J/psi suppression that accounts for rapidity and other dependencies, aligning well with experimental observations without needing sequential decay mechanisms.

Findings

Model agrees with PHENIX data on J/psi suppression.

Larger suppression observed at forward rapidity.

Direct J/psi production scenario is favored.

Abstract

In order to study the properties of $J/\psi$ (1S) in the deconfining medium, we extend our previous formalism [Phys. Lett. B {\bf 656}, 45 (2007)] on $J/\psi$ suppression at mid-rapidity using the colour screening framework. Our formalism is more general as the complete rapidity, transverse momentum and centrality dependence including $J/\psi$ suppression at forward as well as mid-rapidity can be computed directly from it. Careful attention is paid to the role of the medium's proper time in determining the locus of the screening region where $J/\psi$ gets suppressed. Other important ingredients in the calculation are bag model equation of state for QGP, the longitudinal expansion of the QGP fluid obeying Bjorken's boost invariant scaling law and non-sequential/sequential melting of $\chi_c$ (1P) as well as $\psi^{'}$ (2S) higher resonances. Upon comparison with the recent data of PHENIX collaboration on $J/\psi$ suppression at forward and mid-rapidity regions, we find that our model shows a reasonable agreement with the data without incorporating any sequential decay mechanism of higher charmonia states. Furthermore, we observe a larger suppression at forward rapidity in our model which is again well supported by the PHENIX data and also gives a hint that a scenario based on directly produced $J/\psi$'s is preferable.