Impact Of ATLAS Z Boson Transverse Momentum Distribution On PDFs

Parton Distribution Functions(PDFs)is one of the indispensable tools for the theoretical prediction of the proton-proton collider,proton-antiproton collider,leptonhadron collider,and other high energy physics experiments.And it plays an important role in the accurate measurement of high energy physics experiments and the discovery of new physics beyond the standard model.However,the PDF is nonperturbative and cannot be calculated based on first principles.The general approach for obtaining PDFs is to combine new data with the old data that were included to fit old PDFs,and to do a global Quantum Chromodynamic analysis.In this thesis,we use the Error PDF Updating method Package(ePump)to study the impact of the ATLAS 8 TeV Z boson transverse momentum data on the CT14HERA2 parton distribution functions.In this method we do not need to do complicated global QCD analysis,however by inputting new data with associated statistical and systematical uncertainties,and corresponding theory calculations,we obtain quickly a new PDFs that approximates a global analysis.By using numerical calculation tool ResBos and CT14HERA2 PDFs,we calculate the differential scattering cross sections(d?/dpT)of the six transverse momentum distributions of the six different mass regions of the Z boson production process at 8 TeV.Our results show that the predictions from ResBos are consistent with the data within the uncertainties.We then use ePump update the CT14HERA2 PDFs.The results show that the ATLAS 8TeV Z boson transverse momentum data for 12GeV<Mll<30GeV,reduce the central value of the CT14HERA2+ZpT20 d-quark PDF by about 2%relative to the central value of the CT14HERA2 d-quark PDF,at the range 10-4<x<10-2 and at Q=1.3GeV.The data for 30GeV<Mll<46GeV,reduce the central value of the CT14HERA2+ZpT46 d-quark PDF by about 2%relative to the central value of the CT14HERA2 d-quark PDF,at the range 0.6<x<0.9 and at Q=100GeV.The data for 46GeV<Mll<66GeV,reduce the center value of CT14HERA2+ZpT66 d-quark PDF by about 2%relative to the central value of the CT14HERA2 d quark PDF,at the range 10-6<x<10-3 and at Q=100GeV.The data for 66GeV<Mll<116GeV,increase the central value of the CT14HERA2+ZpT116 d-quark PDF by about 16%relative to the center of the CT14HERA2 d-quark PDF,at the range 10-6<x<10-1 and at Q=1.3GeV.