T. Affolder et al., Production of Upsilon(1S) Mesons from chi(b) decays in p(p)over-bar collisions at root s=1.8 TeV, PHYS REV L, 84(10), 2000, pp. 2094-2099
We have reconstructed the radiative decays chi(b)(1P) --> Y(1S)gamma and ch
i(b)(2P) --> Y(1S)gamma in (p) over bar p collisions at root s = 1.8 TeV, a
nd measured the fraction of Y(1S) mesons that originate-from these decays.
For Y(1S) mesons with p(T)(Y) > 8.0 GeV/c, the fractions that come from chi
(b)(1P) and chi(b)(2P) decays are [27.1 +/- 619(stat) +/- 4.4(syst)]% and [
10.5 +/- 4.4(stat) +/- 1.4(syst)]%, respectively. We have derived the fract
ion of directly produced Y(1S) mesons to be [50.9 +/- 8.2(stat) +/- 9.0(sys
t)]%.