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NLO-QCD corrections to $Wγj$ production

F. Campanario, C. Englert, M. Spannowsky, D. Zeppenfeld

TL;DR

Problem: Precision predictions for $W\\gamma j$ production are needed to interpret SM processes and constrain anomalous couplings at hadron colliders. Approach: The authors compute NLO-QCD corrections including leptonic decays of the $W$ with full off-shell effects, using Catani–Seymour dipole subtraction and two independent loop-reduction strategies, embedded in the Vbfnlo framework; photon isolation follows the Frixione prescription. Contributions: They deliver total cross sections and differential distributions for the LHC and Tevatron, finding sizable corrections (roughly 34–41% at the LHC, about 30% at the Tevatron) and significant differential K-factors up to about 60%, along with reduced scale uncertainties. Significance: This work provides the first NLO-QCD predictions for $W\\gamma j$ with leptonic decays and off-shell effects, enabling more reliable SM background estimates and informing future BSM searches and jet-veto strategies, with public code planned via Vbfnlo.

Abstract

We calculate the $W^\pmγj + X$-production cross sections at next-to-leading order QCD for Tevatron and LHC collisions. We include leptonic decays of the $W$ to light leptons, with all off-shell effects taken into account. The corrections are sizable and have significant impact on the differential distributions.

NLO-QCD corrections to $Wγj$ production

TL;DR

Problem: Precision predictions for production are needed to interpret SM processes and constrain anomalous couplings at hadron colliders. Approach: The authors compute NLO-QCD corrections including leptonic decays of the with full off-shell effects, using Catani–Seymour dipole subtraction and two independent loop-reduction strategies, embedded in the Vbfnlo framework; photon isolation follows the Frixione prescription. Contributions: They deliver total cross sections and differential distributions for the LHC and Tevatron, finding sizable corrections (roughly 34–41% at the LHC, about 30% at the Tevatron) and significant differential K-factors up to about 60%, along with reduced scale uncertainties. Significance: This work provides the first NLO-QCD predictions for with leptonic decays and off-shell effects, enabling more reliable SM background estimates and informing future BSM searches and jet-veto strategies, with public code planned via Vbfnlo.

Abstract

We calculate the -production cross sections at next-to-leading order QCD for Tevatron and LHC collisions. We include leptonic decays of the to light leptons, with all off-shell effects taken into account. The corrections are sizable and have significant impact on the differential distributions.

Paper Structure

This paper contains 4 sections, 2 equations, 5 figures, 2 tables.

Table of Contents

  1. Introduction
  2. Elements of the Calculation and Checks
  3. Numerical Results
  4. Summary and Outlook

Figures (5)

  • Figure 1: Representative Feynman graph contributing to the virtual corrections to the partonic subprocess $\bar{u} d\rightarrow e^-\bar{\nu}_e \gamma g$ at ${\@fontswitch\mathcal{O}}(\alpha^3\alpha_s^2)$. The crosses mark other points where the photon is attached to the quark line and the $W$ boson.
  • Figure 2: Sample Feynman graph contributing to the partonic real emission subprocess $\bar{u}d\rightarrow e^- \bar{\nu}_e \gamma g g$ at ${\@fontswitch\mathcal{O}}(\alpha^3\alpha_s^2)$. The gluon is attached to the quark and gluon lines at positions marked by the circles. Feynman graph topologies, where the photon is radiated off at different positions analogous to fig. \ref{['fig:graphvirt']}, are not shown.
  • Figure 3: Comparison of the scale dependence of the total cross section of $pp\rightarrow e^-\bar{\nu}_e \gamma j+X$ at LO (dashed), NLO-QCD (solid), and NLO-QCD with the second jet vetoed (dot-dashed) for the cuts chosen as described in the text at the LHC.
  • Figure 4: Comparison of the scale dependence of the total cross section of $pp\rightarrow e^+\nu_e \gamma j+X$ at LO (dashed), NLO-QCD (solid), and NLO-QCD with the second jet vetoed (dot-dashed) for the cuts chosen as described in the text at the LHC.
  • Figure 6: Differential distribution of the photon-lepton separation $R_{\ell \gamma}$ at LO (dashed) and at NLO (solid). The lower panel shows the differential $K$-factor. The dotted line denotes the total $K$-factor of Tab. \ref{['tab:kfactors']}.