Measurement Of The Z Boson Transverse Momentum Distribution Using Z??~+?~-events At The LHCb Experiment

This thesis describes a measurement of the Z boson transverse momentum dis-tribution using Z??+?-events at the LHCb experiment,the measure result-s are compared t.o RESBOS prediction.The measurement of dilepton t.ransverse momentum(PT)distribution in Z??+?-production could provide stringent test on the Quantum chromodynamics.The data used in this analysis is proton—proton collision data collected at the LHCb experiment in 2016 with a mass cent.er energy of 13 TeV,.integreted luminosity of 1.6fb-1Firstly,we estimate the background contribution for this process.In this experi-ment,where t.he Monte Carlo events are generated with Pythia 8 generator to simu-late the real data?then we use the tag-and-probe method to analyze the Z??+?-events,and determine the reconstruction,ID,trigger efficiency for the high pT?;fi-nally,we unfold the data Z PT using the RooUnfold method to get a precise unfolded result,tht.at,closer its truth level distribution,we performed both efficiencies correc-tions and high-order correction in MC events.The measured results are consistent with the standard model predictions.