Measurement of differential cross sections in the kinematic angular variable $\phi^*$ for inclusive Z boson production in pp collisions at $\sqrt{s}=$ 8 TeV

TL;DR

This paper reports precise measurements of differential cross sections for inclusive Z boson production in proton-proton collisions at 8 TeV, using the CMS detector, and compares them with theoretical models.

Contribution

It provides the first high-precision measurements of dσ/dφ* and d²σ/dφ*dy for Z bosons at 8 TeV, improving understanding of Z boson kinematics.

Findings

Normalized cross sections measured with better than 0.5% precision for φ* < 1

Measurements agree with theoretical predictions within a few percent

Data covers a broad kinematic range with high statistical accuracy

Abstract

Measurements of differential cross sections d$\sigma$/d$\phi^*$ and double-differential cross sections d$^2\sigma$/d$\phi^*\,$d$|y|$ for inclusive Z boson production are presented using the dielectron and dimuon final states. The kinematic observable $\phi^*$ 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 19.7 fb$^{-1}$. The normalised cross section (1/$\sigma$)$\,$d$\sigma$/d$\phi^*$, within the fiducial kinematic region, is measured with a precision of better than 0.5% for $\phi^*$ < 1. The measurements are compared to theoretical predictions and they agree, typically, within few percent.