Psi prime to J/psi Ratio Measurements in PHENIX at RHIC

TL;DR

This paper reports measurements of the ratio of psi' to J/psi production in proton-proton collisions at 200 GeV using the PHENIX detector, providing insights into charmonium production mechanisms.

Contribution

First measurement of the psi' to J/psi ratio in p+p collisions at RHIC energies using dielectron decay channels.

Findings

psi'/J/psi ratio measured as 0.019±0.005(stat)±0.002(sys)

Fractional feed-down from psi' to J/psi is 8.6±2.5%

Results inform charmonium production models at high energies.

Abstract

The ratio of the $\psi'$ over the $J/\psi$ production cross section in the dielectron channel has been measured in $\sqrt{s}=$ 200 GeV $p+p$ collisions with the PHENIX detector at RHIC. The analysis is based on fitting of the dielectron invariant mass spectra in the area around the $J/\psi$ and $\psi'$ signals in order to extract a ratio $\psi'$ over $J/\psi$ of 0.019$\pm 0.005($stat$)\pm 0.002($sys$)$ and a fractional feed-down contribution to $J/\psi$ from $\psi^\prime$ of $8.6 \pm 2.5 %$.