Single and Double differential Drell-Yan cross section measurements using the CMS detector

The neutral current Drell-YanDrell-Yan (DY) process, q $\overline{q}\rightarrow \text {Z}/{\gamma }^{*}\rightarrow l^{+}l^{-}$ , l = $\mu $ , e or $\tau $ , is one of the best-studied benchmark physics processes at the LHC. The large production cross sectionCross section and the experimentally clean final state allows excellent tests for perturbative Quantum Chromodynamics (QCD). A thorough understanding of the tran sverse momentum(p$_T$ ) spectra of the vector bosons at hadron colliders is essential for a future high precision measurement of the mass of the W boson. 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. The phistar ( $\phi ^{*}$ ) variable, which uses the angular correlation of the lepton pairs from Z decay to probe the transverse momenta the vector boson, has intrinsically better resolution and less sensitivity to experimental systematic uncertainties compared to $q_T$ . Results from differential cross-measurements as function of the $\phi ^{*}$ variable will be discussed in the paper.