B-meson production at forward and backward rapidity in $p$+$p$ and Cu+Au collisions at $\sqrt{s_{_{NN}}}$=200 GeV

The fraction of $ J/\ psi$ mesonswhich come from B-mesondecay, $\textrm{F}_{B{\rightarrow}J/\psi}$, is measured for J/$\psi$ rapidity \mbox{$1.2 0$ in $p$+$p$ and Cu+Au collisions at $\sqrt{s_{_{NN}}}$=200 GeV with the PHENIX detector. The extracted fraction is $\textrm{F}_{B{\rightarrow}J/\psi}$ = 0.025 $\pm$ 0.006( stat) $\pm$ 0.010(syst) for $p$+$p$ collisions. For Cu+Au collisions, $\textrm{F}_{B{\rightarrow}J/\psi}$ is 0.094 $\pm$ 0.028( stat) $\pm$ 0.037(syst) in the Au-going direction ($-2.2 stat) $\pm$ 0.040(syst) in the Cu-going direction ($1.2 B mesonsin Cu+Au collisions is consistent with binary scalingof measured yields in $p$+$p$ at both forward and backward rapidity.