Hard hadronic diffraction is not hard

TL;DR

This paper challenges the traditional view that hard diffractive processes are suppressed and shows they are actually leading twist, affecting predictions for various diffractive particle productions.

Contribution

It demonstrates that hard diffraction processes are leading twist, contradicting previous assumptions of higher twist classification, and discusses implications for particle production.

Findings

Hard diffraction is a leading twist process.

Breakdown of factorization in hard diffractive interactions.

Implications for diffractive production of gauge bosons, Higgs, and heavy flavors.

Abstract

Hadronic diffractive processes characterised by a hard scale (hard diffraction) contain a nontrivial interplay of hard and soft, nonperturbative interactions, which breaks down factorisation of short and long distances. On the contrary to the expectations based on the factorization hypothesis, assuming that hard diffraction is a higher twist, these processes should be classified as a leading twist. We overview various implications of this important observation for diffractive radiation of Abelian (Drell-Yan, gauge bosons, Higgs boson) and non-Abelian (heavy flavors) particles, as well as direct coalescence into the Higgs boson of the non-perturbative intrinsic heavy flavour component of the hadronic wave function.