Measurements of e(+)e(-) pairs from open heavy flavor in p plus p and d plus A collisions at root S-NN=200 GeV
Abstract
We report a measurement of e(+)e(-) pairs from semileptonic heavy-flavor decays in p + p collisions at root S-NN = 200 GeV. The e(+)e(-) pair yield from b (b) over bar and c (c) over bar is separated by exploiting a double differential fit done simultaneously in dielectron invariant mass and p(T).
We used three different event generators, PYTHIA, MC@NLO, and POWHEG, to simulate the e(+)e(-) spectra from c (c) over bar and b (b) over bar production. The data can be well described by all three generators within the detector acceptance.
However, when using the generators to extrapolate to 4 pi, significant differences are observed for the total cross section. These difference are less pronounced for b (b) over bar than for c (c) over bar.
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 p(T), and within the statistical accuracy no nuclear modification is seen.