Precise predictions for W γγ+jet production at hadron colliders

TL;DR

This work delivers the first next-to-leading order QCD calculation for triboson+jet production, specifically pp → W γ γ + jet + X with leptonic W decays and all off-shell/finite-width effects. The authors implement a comprehensive framework that combines real emission with Catani–Seymour subtraction, high-point virtuals up to hexagons, and an effective current approach to capture W width, using a dynamical scale and Frixione photon isolation. They find sizable K-factors (~1.4) with nontrivial phase-space dependence, notably altering high-mass and high-pT regions of key distributions, which has important implications for searches of anomalous electroweak quartic couplings. These results provide essential guidance for precision phenomenology and for interpreting collider data in the context of potential beyond-Standard-Model effects.

Abstract

In this letter we report on a calculation of W gamma gamma + jet production at next-to-leading order QCD. We include the leptonic decays of the W and take into account all off-shell and finite width effects. This is the first computation which falls into the category of triboson+jet production at next-to-leading order QCD. In total we find sizable corrections with nontrivial phase space dependencies. Therefore, our results are important for phenomenological analyses such as the extraction of anomalous electroweak quartic couplings from inclusive hadron collider data.

Figures (6)

• Figure 1: Selected topologies contributing to $W^-\gamma\gamma$+jet production at NLO; $i=1,2$ denotes the generation index. Note that we do not show the contributions $W^{\star}_n\rightarrow e^-\bar{\nu}_e + (n-2)\gamma$, $2\leq n \leq 4$. These lead to identical configurations from the QCD point of view. The red loops indicate the virtual contributions, giving rise to topologies of up to boxes (a,b), up to pentagons (c) and up to hexagons (d).
• Figure 2: Fermion loop contributions to $W\gamma\gamma$+jet production at NLO; $i=1,2,3$ denotes the generation index. $q$ stands for all (anti)quark flavors of the incoming (anti)proton. Note that analogous $gg\gamma$ triangle contributions are forbidden by Furry's theorem. Not shown are topologies where the polarization vector $W^{\star}_2$ is attached to the initial state (anti)quark, and where the internal and external gluon are attached at opposite corners of the box.
• Figure 3: Scale variation of the $\ell^\pm \nu \gamma\gamma$+jet production cross sections at the LHC ($\ell$ = $e$, $\mu$). The cuts are described in the text and we take the invariant $W\gamma\gamma$ mass $m_{W\gamma\gamma}$ as central dynamical reference scale. The left panel shows the variation of the LO and NLO $W^+\gamma\gamma$+jet production cross sections when we change only the factorization scale, only the renormalization scale, or both jointly. For $W^-\gamma\gamma$+jet production the right panel shows the individual contributions to the NLO cross section, as discussed in the text. Here we also present results where we have applied a veto on events with two identified jets having both a transverse momentum larger than 50 GeV.
• Figure 4: Differential $\max p_T^j$ distribution for $W^-\gamma\gamma$+jet production. The chosen cuts and scales are described in text. The horizontal line in the lower panel displays the $K$ factor for total inclusive production, Tab. \ref{['tab:xsecs']}.
• Figure 5: $W\gamma\gamma$ invariant mass distribution for $W^-\gamma\gamma$+jet production. The chosen cuts and scales are described in text. The horizontal line in the lower panel displays the $K$ factor for total inclusive production, Tab. \ref{['tab:xsecs']}.