Photon induced corrections to Drell-Yan production in POWHEG

Abstract

High-precision theoretical predictions for both signal and background processes are crucial for the precision physics program at the LHC and HL-LHC. A prime example is the determination of the effective leptonic weak mixing angle from neutral current Drell-Yan via template-fit methods, where Monte Carlo templates directly serve as input to the measurement, making theoretical uncertainties part of the systematic error affecting the experimental results. In this paper, we focus on photon-induced corrections to neutral current Drell-Yan, as well as on the irreducible $\gamma\gamma \to l^+l^-$ background. We present the implementation of the photon-initiated contributions in the Z_ew-BMNNPV Monte Carlo generator for Drell-Yan production at NLO QCD + NLO EW accuracy matched to QED and QCD parton showers within the POWHEG framework. We discuss phenomenological results for the dilepton invariant-mass distribution and the forward-backward asymmetry in the Z-resonance region and in the TeV range.