Discriminating the heavy jet production mechanisms in associated $Z$ + heavy flavor events at the LHC

TL;DR

This paper compares two theoretical approaches to heavy jet production in association with Z bosons at the LHC, using new observables to distinguish their formation mechanisms and aligning predictions with recent experimental data.

Contribution

It introduces two kinematic observables to discriminate heavy jet production mechanisms and compares different theoretical schemes with experimental data at 13 TeV.

Findings

The proposed observables effectively differentiate production mechanisms.

Both theoretical approaches show varying degrees of agreement with experimental data.

Recommendations are made for future experimental analyses using these observables.

Abstract

We reconsider the associated $Z$ boson and charm or beauty jet production at the LHC with paying special attention to the formation dynamics of heavy jets. Two different approaches are studied: first one, where heavy quarks are produced in the hard scattering subprocesses, implemented in the Monte-Carlo generator PEGASUS, and another scenario, where the hard scattering is calculated at NLO with MadGraph5_aMC@NLO and TMD parton shower is included (implemented in the Monte-Carlo generator CASCADE3). We compare the predictions obtained in both schemes with latest experimental data for associated $Z + b$ production cross sections and the relative production rate $\sigma(Z + c)/\sigma(Z + b)$ collected by the ATLAS and CMS Collaborations at $\sqrt s = 13$~TeV. We introduce two kinematic observables (denoted as $z_b$ and $p_T^{\rm rel}$) which can be used to discriminate the heavy jet production mechanisms. Using these variables we trace the shape of the simulated $b$-jet events and recommend that these observables be taken into consideration in the forthcoming experimental analyses.