Description of $Z$ Boson Mass and $p_T$ Spectrum at LHC Using Leading-Order Event Generators at $\sqrt{s} = 13.6$ TeV

In this paper, we report a study of $Z$ boson kinematic distributions in the $Z$+ 1-jet events from proton-proton ($pp$) collisions at $\sqrt{s}$ = 13.6 TeV at the Large Hadron Collider (LHC) using Leading-Order (LO) event generators. Three LO event generators, namely Pythia8, Herwig7 and Sherpa2, are explored with the implementation of appropriate Parton Shower (PS) and Matrix Element (ME) corrections. The $Z$ boson is reconstructed from oppositely charged di-lepton pairs ($\mu^+\mu^-$ and $e^+e^-$), and the associate leading jet is reconstructed with the anti-$k_T$ algorithm with radius $r$=0.4. The di-lepton invariant mass, $M_{\ell^+\ell^-}$, and the transverse momentum of the reconstructed $Z$ boson, $p_{T}^Z$, distributions are extensively studied by comparing three of the Monte Carlo (MC) predictions. In addition to this, we also explore several other kinematic distributions associated with the candidate lepton and the jet to distinguish the modelling of the LO event generators in depth. Furthermore, various showering modules within these event generators are explored for $Z$ + 1-jet production. While the three of these MC frameworks reproduce the $Z$ + 1-jet kinematics similarly, certain discrepancies in their predictions are identified in some variables. We analyzed them using different statistical tests. The best match of the $p_{T}^Z$ spectra was found between the Pythia8 and Sherpa2 results.
Comment: 29 pages