Measurements of e+e− pairs from open heavy flavor in p + p and d + A collisions at √ sNN = 200 GeV

We report a measurement of e+e− pairs from semileptonic heavy-flavor decays in p + p collisions at √sNN = 200 GeV. The e+e− pair yield from bb¯ and cc¯ is separated by exploiting a double differential fit done simultaneously in dielectron invariant mass and pT . We used three different event generators, PYTHIA,MC@NLO, and POWHEG, to simulate the e+e− spectra from cc¯ and bb¯ production. The data can be well described by all three generators within the detector acceptance. However, when using the generators to extrapolate to 4π, significant differences are observed for the total cross section. These difference are less pronounced for bb¯ than for cc¯. The same model dependence was observed in already published d + A data. The p + p data are also directly compared with d + A data in mass and pT , and within the statistical accuracy no nuclear modification is seen.