Anomalous triple gauge couplings in electroweak dilepton tails at the LHC and interference resurrection

TL;DR

This paper investigates the measurement of anomalous triple gauge couplings in electroweak dilepton production at the LHC, highlighting the interference effects and proposing new analysis techniques to improve sensitivity.

Contribution

It introduces the concept of interference resurrection in electroweak processes, proposes the VBFhardness variable for better analysis, and provides a detailed sensitivity study for anomalous couplings at the LHC.

Findings

Interference effects can be enhanced with a new kinematic cut.

The VBFhardness variable effectively controls energy flow into dilepton subprocess.

Sensitivity to anomalous couplings improves with optimized cuts and analysis.

Abstract

We study the electroweak dilepton production with two forward jets at the LHC, aiming to measure the anomalous triple gauge couplings in the Effective Field Theory (EFT) approach. This process exhibits a distinctive feature, namely, the interference between Standard Model (SM) and beyond the SM is resurrected in the inclusive cross section of the full amplitude, including two forward jets. As a concrete illustration, we perform the detailed analytic and numerical study of the interference using a simpler toy process, and discuss the subtlety of the effective W approximation. We propose a new kinematic variable, VBFhardness, that controls the amount of energy flowing into the dilepton subprocess. We show that an appropriate cut on VBFhardness makes the interference resurrection manifest. Finally, we use the invariant mass of the dilepton system as well as the transverse momentum, as done in the literature, to derive the sensitivity to anomalous triple gauge couplings at the LHC and the high luminosity LHC. Our result is compared with the existing limits from the experiments.