Interplay between IR-Improved DGLAP-CS Theory and the Precision of an NLO ME Matched Parton Shower MC in Relation to LHCb Data

TL;DR

This paper evaluates the accuracy of an exact amplitude-based resummation approach in quantum field theory for precision QCD calculations by comparing its predictions with recent LHCb data on Z/ production, extending previous studies with CMS and ATLAS data.

Contribution

It demonstrates the application of IR-improved DGLAP-CS theory combined with NLO matrix element matched parton shower Monte Carlo to LHCb data, advancing precision QCD modeling for LHC physics.

Findings

Good agreement between theory and LHCb data across extended phase space.

Validation of the resummation approach for precision predictions.

Supports the use of this method for future LHC analyses.

Abstract

We use comparison with recent LHCb data on single Z/\gamma^* production and decay to lepton pairs as a vehicle to study the current status of the application of our approach of {\it exact} amplitude-based resummation in quantum field theory to precision QCD calculations, by realistic MC event generator methods, as needed for precision LHC physics. This represents an extension of the phase space of our previous studies based on comparison with CMS and ATLAS data, as the pseudo-rapidity range measured by the LHCb for leptons in the data we study is 2.0<\eta< 4.5 to be compared with |\eta|<4.6(2.4) in our previous CMS(ATLAS) data comparison for the same processes. The analyses we present here with the LHCb data thus represent an important addition to our previous results, as it is essential that theoretical predictions be able to control all of the measured phase space at LHC. The level of agreement between the new theory and the data continues to be a reason for optimism.