A study of final-state radiation in decays of Z bosons produced in pp collisions at 7 TeV

TL;DR

This paper measures the production of photons in Z boson decays at 7 TeV, comparing experimental data with simulations to test the accuracy of theoretical models of final-state radiation.

Contribution

It provides detailed differential cross sections for photon production in Z decays and evaluates the agreement with simulations, enhancing understanding of final-state radiation in high-energy collisions.

Findings

Simulations match data within 5%

Differential cross sections as a function of photon energy and separation

Validation of PYTHIA and POWHEG models for final-state radiation

Abstract

The differential cross sections for the production of photons in Z to mu+ mu- gamma decays are presented as a function of the transverse energy of the photon and its separation from the nearest muon. The data for these measurements were collected with the CMS detector and correspond to an integrated luminosity of 4.7 inverse femtobarns of pp collisions at sqrt(s) = 7 TeV delivered by the CERN LHC. The cross sections are compared to simulations with POWHEG and PYTHIA, where PYTHIA is used to simulate parton showers and final-state photons. These simulations match the data to better than 5%.