Study of weak corrections to Drell-Yan, top-quark pair and dijet Production at high energies with MCFM

TL;DR

This paper implements next-to-leading order electroweak corrections into the MCFM Monte Carlo program for Drell-Yan, top-quark pair, and dijet production, enabling precise high-energy collider predictions.

Contribution

It introduces the first implementation of NLO electroweak corrections for these processes in MCFM, including both full and Sudakov approximation results.

Findings

Electroweak corrections become significant at high energies.

The Sudakov approximation is validated against full NLO corrections.

Combined electroweak and QCD corrections improve prediction accuracy.

Abstract

Electroweak (EW) corrections can be enhanced at high energies due to the soft or collinear radiation of virtual and real $W$ and $Z$ bosons that result in Sudakov-like corrections of the form $\alpha_W^l\log^n(Q^2/M_{W,Z}^2)$, where $\alpha_W =\alpha/(4\pi\sin^2\theta_W)$ and $n\le 2l-1$. The inclusion of EW corrections in predictions for hadron colliders is therefore especially important when searching for signals of possible new physics in distributions probing the kinematic regime $Q^2 \gg M_V^2$. Next-to-leading order (NLO) EW corrections should also be taken into account when their size ($\mathcal{O}(\alpha)$) is comparable to that of QCD corrections at next-to-next-to-leading order (NNLO) ($\mathcal{O}(\alpha_s^2)$). To this end we have implemented the NLO weak corrections to the Neutral-Current Drell-Yan process, top-quark pair production and di-jet production in the parton-level Monte-Carlo program MCFM. This enables a combined study with the corresponding QCD corrections at NLO and NNLO. We provide both the full NLO weak corrections and their Sudakov approximation since the latter is often used for a fast evaluation of weak effects at high energies and can be extended to higher orders. With both the exact and approximate results at hand, the validity of the Sudakov approximation can be readily quantified