Drell--Yan lepton pair production at low invariant masses: transverse-momentum resummation and non-perturbative effects in QCD

TL;DR

This paper provides precise QCD predictions for the transverse momentum distribution of low-mass Drell-Yan lepton pairs, combining advanced resummation techniques with non-perturbative effects and validating against collider data.

Contribution

It introduces a comprehensive approach combining high-order resummation with non-perturbative modeling for low-$q_T$ Drell-Yan production, improving theoretical accuracy and data agreement.

Findings

Excellent agreement with collider data across $4 \,\text{GeV} \leq M \leq 116 \,\text{GeV}$

Precise extraction of non-perturbative form factors and Collins-Soper kernel

Validation of resummation and non-perturbative models at NNLL and NNLO levels

Abstract

We consider the transverse-momentum ($q_T$) distribution of Drell-Yan lepton pairs produced with invariant masses ($M$) from low values up to the $Z$-boson peak ($4\leq M \leq 116$~GeV). We present perturbative predictions obtained by consistently combining the resummation of logarithmically enhanced QCD corrections at small $q_T$ ($q_T \ll M$) up to next-to-next-to-next-to-next-to-leading logarithmic accuracy with the available fixed-order calculations at next-to-next-to-leading order (i.e. $\mathcal{O}(\alpha_S^3)$) valid at large $q_T$. For very low $q_T$ ($q_T\sim \Lambda_{\mathrm{QCD}}$), non-perturbative (NP) QCD effects become dominant and have been included through a NP form factor with a small number of free-parameters. We compare our results with multiple experimental datasets from hadron colliders, finding excellent agreement between theory and data. By fitting the NP parameters, we achieve a precise extraction of the NP form factor and the so-called Collins-Soper kernel.