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

PHENIX reports differential cross sections of $mumu$ 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 ($1.2u003c|eta|u003c2.2$). The $mumu$ pairs from $cbar{c}$, $bbar{b}$, and Drell-Yan are separated using a simultaneous fit to unlike- and like-sign muon pair spectra in mass and $p_T$. The azimuthal opening angle correlation between the muons from $cbar{c}$ and $bbar{b}$ 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 $cbar{c}$ are consistent with {sc pythia} calculations. The $cbar{c}$ data presents narrower azimuthal correlations and softer $p_T$ distributions compared to distributions generated from {sc powheg}. The $bbar{b}$ 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.