1. chinaXiv:201609.00899 [pdf]

An updated study of $\Upsilon$ production and polarization at the Tevatron and LHC

Yu Feng; Bin Gong; Lu-Ping Wan; Jian-Xiong Wang
Subjects: Physics >> Nuclear Physics

Following the nonrelativistic QCD factorization scheme, by taking latest available measurement on?χb(3P)?into consideration, we present an updated study on the yield and polarization of?Υ(1S,2S,3S)?hadroproduction, and the fractions of?χb(mP)?feed-down in?Υ(nS)?production at QCD next-to-leading order. In the fitting, three schemes are applied with different choice of?χb(mP)?feed-down ratios and NRQCD factorization scale. The results can explain the measurements on yield very well as in our previous work. The polarization puzzle to?Υ(3S)?is now solved by considering the?χb(3P)?feed-down contributions. The ratio of?σ[χb2(1P)]/σ[χb1(1P)]?measurements from CMS can also be reproduced in our prediction. Among the different schemes, the results show little difference, but there are sizeable difference for the fitted long-distance color-octet matrix elements. It may bring large uncertainty when the values are applied in other experiments such as in?ee,?ep?colliders.

submitted time 2016-09-13 Hits620， Downloads370， Comment 0