Reduction of PDF uncertainty in the measurement of the weak mixing angle at the ATLAS experiment  

作　　者：Yao Fu Siqi Yang Minghui Liu Liang Han Tie-Jiun Hou Carl Schmidt Chen Wang C-P.Yuan 付尧;杨思奇;刘明辉;韩良;侯铁君;Carl Schmidt;王晨;C-P.Yuan(Department of Modern Physics,University of Science and Technology of China,Jinzhai Road 96,Hefei 230026,China;Department of Physics,College of Sciences,Northeastern University,Shenyang 110819,China;Department of Physics and Astronomy,Michigan State University,East Lansing,MI 48823,USA)

机构地区：[1]Department of Modem Physics,University of Science and Technology of China,Jinzhai Road 96,Hefei 230026,China [2]Department of Physics,College of Sciences,Northeastern University,Shenyang 110819,China [3]Department of Physics and Astronomy,Michigan State University,East Lansing,MI 48823,USA

出　　处：《Chinese Physics C》2021年第5期1-18,共18页中国物理C（英文版）

基　　金：the National Natural Science Foundation of China(11721505,11875245);the U.S.National Science Foundation(PHY-2013791)。

摘　　要：We investigate the parton distribution function(PDF)uncertainty in the measurement of the effective weak mixing angle sin2θ^(l)_(eff)at the CERN Large Hadron Collider(LHC).The PDF-induced uncertainty is large in proton-proton collisions at the LHC due to the dilution effect.The measurement of the Drell-Yan forward-backward asymmetry(ApB)at the LHC can be used to reduce the PDF uncertainty in the sin2θ^(l)_(eff)measurement.However,when including the full mass range of lepton pairs in the AFB data analysis,the correlation between the PDF updating procedure and the sin2θ^(l)_(eff) extraction leads to a sizable bias in the obtained sin2θ^(l)_(eff)value.From our studies,we find that the bias can be significantly reduced by removing Drell-Yan events with invariant mass around the Z-pole region,while most of the sensitivity in reducing the PDF uncertainty remains.Furthermore,the lepton charge asymmetry in the^boson events as a function of the rapidity of the charged leptons,A±(ηl),is known to be another observable which can be used to reduce the PDF uncertainty in the sin2θ^(l)_(eff)measurement.The constraint from A±(ηl)is complementary to that from AFB,and thus no bias affects the sin2θ^(l)_(eff)extraction.The studies are performed using the error PDF Updating Method Package(ePump),which is based on Hessian updating methods.In this article,the CT14HERA2 PDF set is used as an example.

关 键 词：parton distribution function weak mixing angle hadron collider experiment ELECTROWEAK 

分 类 号：O572.214[理学—粒子物理与原子核物理]