Production of Y(1S) Mesons from chib Decays in pp(bar) Collisions at sqrt(s)=1.8 TeV

Abstract

We have reconstructed the radiative decays $χ_{b}(1P) \to Υ(1S) γ$ and $χ_{b}(2P) \to Υ(1S) γ$ in $p \bar{p}$ collisions at $\sqrt{s} = 1.8$ TeV, and measured the fraction of $Υ(1S)$ mesons that originate from these decays. For $Υ(1S)$ mesons with $p^Υ_{T}>8.0$ GeV/$c$, the fractions that come from $χ_{b}(1P)$ and $χ_{b}(2P)$ decays are $(27.1\pm6.9(stat)\pm4.4(sys))%$ and $(10.5\pm4.4(stat)\pm1.4(sys))%$, respectively. We have derived the fraction of directly produced $Υ(1S)$ mesons to be $(50.9\pm8.2(stat)\pm9.0(sys))%$.