J/$\psi$ and $\psi(2S)$ measurement in p+p collisions at $\sqrt{s} =$ 200 and 500 GeV with the STAR experiment

TL;DR

This paper reports measurements of J/psi and psi(2S) production and polarization in proton-proton collisions at 200 and 500 GeV, providing insights into quarkonium production mechanisms at these energies.

Contribution

It presents the first measurements of J/psi production as a function of multiplicity and the psi(2S) to J/psi ratio at 500 GeV in p+p collisions.

Findings

J/psi cross section and polarization measured at both energies.

First measurement of J/psi production versus charged-particle multiplicity.

Psi(2S) to J/psi ratio reported at 500 GeV.

Abstract

In this paper, results on the J/psi cross section and polarization measured via the dielectron decay channel at mid-rapidity in p+p collisions at 200 and 500 GeV in the STAR experiment are discussed. Also, first measurements of the J/psi production as a function of the charged-particle multiplicity density and of psi(2S) to J/psi ratio at 500 GeV are reported.