Upsilon cross section in p+p collisions at sqrt(s) = 200 GeV

TL;DR

This paper measures the Upsilon production cross section in proton-proton collisions at 200 GeV, compares it with theoretical models, and extends Upsilon data to RHIC energies, providing insights into quarkonium production.

Contribution

First measurement of Upsilon cross section at 200 GeV in p+p collisions, testing perturbative QCD models at RHIC energies.

Findings

Measured Upsilon cross section: 114 +/- 38 (stat.) +23,-24 (syst.) pb.

Perturbative QCD at NLO agrees with measurement, Color Singlet Model underestimates.

Results align with global energy trend and extend Upsilon data to RHIC energies.

Abstract

We report on a measurement of the Upsilon(1S+2S+3S) -> e+e- cross section at midrapidity in p+p collisions at sqrt(s)=200 GeV. We find the cross section to be 114 +/- 38 (stat.) +23,-24 (syst.) pb. Perturbative QCD calculations at next-to-leading order in the Color Evaporation Model are in agreement with our measurement, while calculations in the Color Singlet Model underestimate it by 2 sigma. Our result is consistent with the trend seen in world data as a function of the center-of-mass energy of the collision and extends the availability of Upsilon data to RHIC energies. The dielectron continuum in the invariant mass range near the Upsilon is also studied to obtain a combined cross section of Drell-Yan plus (b b-bar) -> e+e-.