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Aidala, C.*; 長谷川 勝一; 今井 憲一; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他287名*
Physical Review D, 99(7), p.072003_1 - 072003_41, 2019/04
被引用回数:15 パーセンタイル:64.26(Astronomy & Astrophysics)PHENIX reports differential cross sections of pairs from semileptonic heavy-flavor decays and the Drell-Yan production mechanism measured in collisions at GeV at forward and backward rapidity (). The pairs from , , and Drell-Yan are separated using a simultaneous fit to unlike- and like-sign muon pair spectra in mass and . The azimuthal opening angle correlation between the muons from and decays and the pair- distributions are compared to distributions generated using and models, which both include next-to-leading order processes. The measured distributions for pairs from are consistent with calculations. The data presents narrower azimuthal correlations and softer distributions compared to distributions generated from . The data are well described by both models. The extrapolated total cross section for bottom production is [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.
Aidala, C.*; 長谷川 勝一; 今井 憲一; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他287名*
Physical Review D, 98(7), p.072004_1 - 072004_13, 2018/10
被引用回数:2 パーセンタイル:12.69(Astronomy & Astrophysics)Dihadron and isolated direct photon-hadron angular correlations are measured in collisions at GeV. The correlations are sensitive to nonperturbative initial-state and final-state transverse momentum and in the azimuthal nearly back-to-back region . In this region, transverse-momentum-dependent evolution can be studied when several different hard scales are measured. To have sensitivity to small transverse momentum scales, nonperturbative momentum widths of , the out-of-plane transverse momentum component perpendicular to the trigger particle, are measured. These widths are used to investigate possible effects from transverse-momentum-dependent factorization breaking. When accounting for the longitudinal momentum fraction of the away-side hadron with respect to the near-side trigger particle, the widths are found to increase with the hard scale; this is qualitatively similar to the observed behavior in Drell-Yan and semi-inclusive deep-inelastic scattering interactions. The momentum widths are also studied as a function of center-of-mass energy by comparing to previous measurements at GeV. The nonperturbative jet widths also appear to increase with at a similar , which is qualitatively consistent to similar measurements in Drell-Yan interactions.