Ground and excited charmonium state production in p+p collisions at sqrt(s)=200 GeV

TL;DR

This paper presents measurements of charmonium states in proton-proton collisions at 200 GeV, analyzing their production rates, decay contributions, and dependencies on transverse momentum and rapidity, providing insights into charmonium production mechanisms.

Contribution

It provides new high-statistics measurements of J/psi, psi', and chi_c production, including feed-down fractions and kinematic dependencies, enhancing understanding of charmonium production in p+p collisions.

Findings

Feed-down fraction from psi' is 9.6%

Feed-down fraction from chi_c is 32%

J/psi yield depends on p_T and rapidity

Abstract

We report on charmonium measurements [J/psi(1S), psi'(2S), and chi_c(1P)] in p+p collisions at sqrt(s)=200 GeV. We find that the fraction of J/psi coming from the feed-down decay of psi' and chi_c in the midrapidity region ($|\eta|<0.35$) is 9.6+/-2.4% and 32+/-9%, respectively. We also report new, higher statistics p_T and rapidity dependencies of the J/psi yield via dielectron decay in the same midrapidity range and at forward rapidity (1.2<|eta|<2.4) via dimuon decay. These results are compared with measurements from other experiments and discussed in the context of current charmonium production models.