Study of Z bosons plus jets events using variables sensitive to double-parton scattering in pp collisions at 13 TeV

TL;DR

This paper investigates double-parton scattering in proton-proton collisions at 13 TeV by analyzing Z boson plus jets events, measuring differential cross sections, and comparing distributions with various event generator predictions to improve simulation models.

Contribution

It introduces new measurements of Z + jets events sensitive to double-parton scattering effects and evaluates the impact of different hadronization and multiparton interaction models.

Findings

Distributions depend on hadronization and MPI parameters

Measurements provide input for refining simulation models

Differential cross sections for Z + ≥1 and ≥2 jets are reported

Abstract

Double-parton scattering is investigated using events with a Z boson and jets. The Z boson is reconstructed using only the dimuon channel. The measurements are performed with proton-proton collision data recorded by the CMS experiment at the LHC at $\sqrt{s} =$ 13 TeV, corresponding to an integrated luminosity of 35.9 fb$^{-1}$ collected in the year 2016. Differential cross sections of Z + $\geq$ 1 jet and Z + $\geq$ 2 jets are measured with transverse momentum of the jets above 20 GeV and pseudorapidity $|\eta|$ $\lt$ 2.4. Several distributions with sensitivity to double-parton scattering effects are measured as functions of the angle and the transverse momentum imbalance between the Z boson and the jets. The measured distributions are compared with predictions from several event generators with different hadronization models and different parameter settings for multiparton interactions. The measured distributions show a dependence on the hadronization and multiparton interaction simulation parameters, and are important input for future improvements of the simulations.