Measurements of $\mu\mu$ pairs from open heavy flavor and Drell-Yan in $p+p$ collisions at $\sqrt{s}=200$ GeV

TL;DR

This paper measures muon pairs from heavy-flavor decays and Drell-Yan processes in proton-proton collisions at 200 GeV, comparing results to theoretical models and providing insights into heavy-flavor production mechanisms.

Contribution

It provides the first detailed differential cross sections of muon pairs from heavy-flavor decays and Drell-Yan at this energy, with model comparisons and extrapolated cross sections.

Findings

car{c} data aligns with Pythia, but shows narrower azimuthal correlations

bar{b} data agrees with both Pythia and POWHEG models

Extrapolated bottom production cross section matches previous RHIC results

Abstract

PHENIX reports differential cross sections of $\mu\mu$ pairs from semileptonic heavy-flavor decays and the Drell-Yan production mechanism measured in $p$$+$$p$ collisions at $\sqrt{s}=200$ GeV at forward and backward rapidity ($1.2<|\eta|<2.2$). The $\mu\mu$ pairs from $c\bar{c}$, $b\bar{b}$, and Drell-Yan are separated using a template fit to unlike- and like-sign muon pair spectra in mass and $p_T$. The azimuthal opening angle correlation between the muons from $c\bar{c}$ and $b\bar{b}$ decays and the pair-$p_T$ distributions are compared to distributions generated using {\sc pythia} and {\sc powheg} models, which both include next-to-leading order processes. The measured distributions for pairs from $c\bar{c}$ are consistent with {\sc pythia} calculations. The $c\bar{c}$ data presents narrower azimuthal correlations and softer $p_T$ distributions compared to distributions generated from {\sc powheg}. The $b\bar{b}$ data are well described by both models. The extrapolated total cross section for bottom production is $3.75{\pm}0.24({\rm stat}){\pm}^{0.35}_{0.50}({\rm syst}){\pm}0.45({\rm global})$[$\mu$b], 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 two higher than the central value calculated with theoretical models. The measured Drell-Yan cross section is in good agreement with next-to-leading-order quantum-chromodynamics calculations.