We report a measurement of $e^+e^-$ pairs from semileptonic heavy-flavor decays in $d$$+$Au collisions at $\sqrt{ s_{ _{ NN}}}=200$ GeV. Exploring the mass and transverse-momentum dependence of the yield, the bottom decay contribution can be isolated from charm, and quantified by comparison to { \sc pythia} and { \sc mc@nlo} simulations. The resulting $b\bar{ b}$-production cross section is $\sigma^{ d{ \rm Au}}_{ b\bar{ b}}=1.37{ \pm}0.28({ \rm stat}){ \pm}0.46({ \rm syst})$~mb, which is equivalent to a nucleon-nucleon cross section of $\sigma^{ NN}_{ bb}=3.4\pm0.8({ \rm stat}){ \pm}1.1({ \rm syst})\ \mu$b.
Categories: nucl-ex