An updated study of Υ production and polarization at the Tevatron and LHC  

作　　者：冯宇 龚斌 万露萍 王建雄 

机构地区：[1]Institute of High Energy Physics,Chinese Academy of Sciences

出　　处：《Chinese Physics C》2015年第12期25-32,共8页中国物理C（英文版）

基　　金：Supported by National Nature Science Foundation of China(11475183);Youth Innovation Promotion Association of CAS(2014010)

摘　　要：Following the nonrelativistic QCD factorization scheme, by taking the latest available measurements of XbJ（3P） into consideration, we present an updated study on the yield and polarization of T（1S, 2S, 3S） hadropro- duction, and the fractions of Xbj（mP） feed-down in T（nS） production at QCD next-to-leading order. In the fitting, three schemes are applied with different choices of XDj（mP） feed-down ratios and NRQCD factorization scale. The results can explain the measurements of yield very well. The polarization puzzle to T（3S） is now solved by consid- ering the XbJ（3P） feed-down contributions. The ratio of σ[Xb2（1P）]/σ[Xbl（IP）] measured by the CMS experiment can also be reproduced in our prediction. Among the different schemes, the results show little difference, but there are sizeable differences for the fitted long-distance color-octet matrix elements. This may bring large uncertainties when the values are applied in theoretical predictions for other experiments such as those at ee, ep colliders.Following the nonrelativistic QCD factorization scheme, by taking the latest available measurements of XbJ（3P） into consideration, we present an updated study on the yield and polarization of T（1S, 2S, 3S） hadropro- duction, and the fractions of Xbj（mP） feed-down in T（nS） production at QCD next-to-leading order. In the fitting, three schemes are applied with different choices of XDj（mP） feed-down ratios and NRQCD factorization scale. The results can explain the measurements of yield very well. The polarization puzzle to T（3S） is now solved by consid- ering the XbJ（3P） feed-down contributions. The ratio of σ[Xb2（1P）]/σ[Xbl（IP）] measured by the CMS experiment can also be reproduced in our prediction. Among the different schemes, the results show little difference, but there are sizeable differences for the fitted long-distance color-octet matrix elements. This may bring large uncertainties when the values are applied in theoretical predictions for other experiments such as those at ee, ep colliders.

关 键 词：non-relativistic quantum chromodynamics next-to-leading order T XbJ feed-down contributions polarization 

分 类 号：O572.243[理学—粒子物理与原子核物理] TL507[理学—物理]