Measurement of differential cross sections in the kinematic angular variable φ∗ for inclusive Z boson production in pp collisions at √s = 8 TeV

Measurements of differential cross sections dσ/dφ∗ and double-differential cross sections d²σ/dφ∗d|y| for inclusive Z boson production are presented using the dielectron and dimuon final states. The kinematic observable φ∗ correlates with the dilepton transverse momentum but has better resolution, and y is the dilepton rapidity. The analysis is based on data collected with the CMS experiment at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 19.7fb^-1. The normalised cross section (1/c) dσ/dφ∗, within the fiducial kinematic region, is measured with a precision of better than 0.5% for φ∗ < 1. The measurements are compared to theoretical predictions and they agree, typically, within few percent.