Nuclear dependence of the production of Υ resonances at 800 GeV

Abstract

The yields of the 1S and the sum of the 2S and 3S \ensuremath{\Upsilon} resonances have been measured for 800-GeV protons incident on targets of $^{2}\mathrm{H}$, C, Ca, Fe, and W. A significant nuclear dependence is seen in the yield per nucleon which, within errors, is the same for the \ensuremath{\Upsilon}(1S) and \ensuremath{\Upsilon}(2S+3D) states. A large decrease in the relative yield from heavy nuclei is found for the range ${\mathit{x}}_{\mathit{F}}$0. Significant nuclear dependence is also observed in the ${\mathit{p}}_{\mathit{t}}$ distribution. Differential cross sections for the \ensuremath{\Upsilon}(1S) for $^{2}\mathrm{H}$ are presented over the ranges 0.24\ensuremath{\le}${\mathit{p}}_{\mathit{t}}$\ensuremath{\le}3.4 GeV/c and -0.15\ensuremath{\le}${\mathit{x}}_{\mathit{F}}$\ensuremath{\le}0.5.