Production of Z^0 bosons with rapidity gaps: exclusive photoproduction in gamma p and p p collisions and inclusive double diffractive Z^0's

TL;DR

This paper extends the k_-factorization formalism to predict the production of Z^0 bosons in gamma p and p p collisions, analyzing distributions and effects relevant for understanding electroweak boson production with rapidity gaps.

Contribution

It introduces a novel application of the k_-factorization formalism to electroweak Z^0 boson production, including predictions for exclusive and inclusive processes with detailed distributions.

Findings

Absorption effects reduce cross sections by a factor of 1.5-2.

Inclusive Z^0 production cross section is about three orders of magnitude larger than exclusive.

Distributions in rapidity, transverse momentum, and azimuthal angle are provided.

Abstract

We extend the k_\perp-factorization formalism for exclusive photoproduction of vector mesons to the production of electroweak Z^0 bosons. Predictions for the gamma p \to Z^0 p and p p \to p p Z^0 reactions are given using an unintegrated gluon distribution tested against deep inelastic data. We present distributions in the Z^0 rapidity, transverse momentum of Z^0 as well as in relative azimuthal angle between outgoing protons. The contributions of different flavours are discussed. Absorption effects lower the cross section by a factor of 1.5-2, depending on the Z-boson rapidity. We also discuss the production of Z^0 bosons in central inclusive production. Here rapidity and (x_{\Pom,1}, x_{\Pom,2}) distributions of Z^0 are calculated. The corresponding cross section is about three orders of magnitude larger than that for the purely exclusive process.