Measurements of μμ pairs from open heavy flavor and Drell-Yan in p + p collisions at √s= 200 GeV

摘要

PHENIX reports differential cross sections of μμ pairs from semileptonic heavy-flavor decays and the Drell-Yan production mechanism measured in p ~+ p collisions at √s= 200 GeV at forward and backward rapidity (1.2 < |η| < 2.2). The μμ pairs from cc, bb, and Drell-Yan are separated using a template fit to unlike- and like-sign muon pair spectra in mass and pT. The azimuthal opening angle correlation between the muons from cc and bb decays and the pair-pT distributions are compared to distributions generated using PYTHIA and POWHEG models, which both include next-to-leading order processes. The measured distributions for pairs from cc are consistent with PYTHIA calculations. The cc data present narrower azimuthal correlations and softer pT distributions compared to distributions generated from POWHEG. The bb data are well described by both models. The extrapolated total cross section for bottom production is 3.75± 0.24(stat)±~(0.35)_(0.50)(syst)± 0.45(global) [μb], which is consistent with previous measurements at the Relativistic Heavy Ion Collider in the same system at the same collision energy and is approximately a factor of 2 higher than the central value calculated with theoretical models. The measured Drell-Yan cross section is in good agreement with next-to-leading-order quantumchromodynamics calculations.