Measurement of φ∗ variable in drell-yan events in p-p collisions using CMS detector at LHC

Abstract

Transverse momentum spectra of vector bosons in Drell-Yan events have always been interesting observables since they test the theoretical description of the process. At lower end the spectrum tests the model of underlying event while the high tail can be compared with predictions from perturbative QCD. However the measurements at LHC are limited due to the resolution in the measurement of momenta of the daughter leptons, electron and muon, in particular. A novel variable phistar has been proposed recently which uses the angular correlation of the lepton pairs from Z decay to probe the transverse momenta the vector boson and hence has less systematic error.