Diffractive gauge bosons production beyond QCD factorisation

Abstract

We discuss single diffractive gauge bosons (${\gamma }^{\ast },W^{\pm },Z$) production in proton-proton collisions at different (LHC and RHIC) energies within the color dipole approach. The calculations are performed for gauge bosons produced at forward rapidities. The diffractive cross section is predicted as function of fractional momentum and invariant mass of the lepton pair. We found a dramatic breakdown of the diffractive QCD factorisation caused by an interplay of hard and soft interactions. Data from the CDF experiment on diffractive production of $W$ and $Z$ are well explained in a parameter free way.

Comments: 28 pages, 10 figures; a clarification of absorptive corrections has been added, typos corrected; the published version