English

An Updated Study for $\Upsilon$ Production and Polarization at the Tevatron and LHC

High Energy Physics - Phenomenology 2015-10-20 v1

Abstract

Following the nonrelativistic QCD factorization scheme, by taking latest available measurement on χb(3P)\chi_b(3P) into consideration, we present an updated study on the yield and polarization of Υ(1S,2S,3S)\Upsilon(1S,2S,3S) hadroproduction, and the fractions of χb(mP)\chi_b(mP) feed-down in Υ(nS)\Upsilon(nS) production at QCD next-to-leading order. In the fitting, three schemes are applied with different choice of χb(mP)\chi_b(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)\Upsilon(3S) is now solved by considering the χb(3P)\chi_b(3P) feed-down contributions. The ratio of σ[χb2(1P)]/σ[χb1(1P)]\sigma[\chi_{b2}(1P)]/\sigma[\chi_{b1}(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, epee,~ep colliders.

Keywords

Cite

@article{arxiv.1503.08439,
  title  = {An Updated Study for $\Upsilon$ Production and Polarization at the Tevatron and LHC},
  author = {Yu Feng and Bin Gong and Lu-Ping Wan and Jian-Xiong Wang},
  journal= {arXiv preprint arXiv:1503.08439},
  year   = {2015}
}