Electroweak vector boson production at the LHC as a probe of mechanisms of diffraction

TL;DR

This paper investigates how electroweak vector boson production in proton-proton collisions at the LHC can distinguish between different QCD-based diffraction mechanisms, highlighting specific asymmetry and ratio predictions.

Contribution

It demonstrates that the W production asymmetry and W/Z ratio in diffractive events serve as clear tests to differentiate resolved Pomeron models from soft color interaction models.

Findings

W production asymmetry is zero in the resolved Pomeron model.

W/Z production ratio is rapidity-independent in the resolved Pomeron model.

Soft color interaction model predicts non-zero asymmetry and rapidity-dependent ratios.

Abstract

We show that the double diffractive electroweak vector boson production in the $pp$ collisions at the LHC is an ideal probe of QCD based mechanisms of diffraction. Assuming the resolved Pomeron model with flavor symmetric parton distributions, the $W$ production asymmetry in rapidity equals exactly zero. In other approaches, like the soft color interaction model, in which soft gluon exchanges are responsible for diffraction, the asymmetry is non-zero and equal to that in the inclusive $W$ production. In the same way, the ratio of the $W$ to $Z$ boson production is independent of rapidity in the models with resolved Pomeron in contrast to the predictions of the soft color interaction model.