Eur. Phys. J. C (2011) 71: 1727
https://doi.org/10.1140/epjc/s10052-011-1727-x

Regular Article - Theoretical Physics

The small x gluon and production at the LHC

¹ Institute for Particle Physics Phenomenology, University of Durham, Durham, DH1 3LE, UK
² Petersburg Nuclear Physics Institute, Gatchina, St. Petersburg, 188300, Russia

^* e-mail: a.d.martin@durham.ac.uk

Received: 29 June 2011
Published online: 19 August 2011

Abstract

We study open production at large rapidity at the LHC in an attempt to pin down the gluon distribution at very low x. For the LHC energy of 7 TeV, at next-to-leading order (NLO), there is a large factorization scale uncertainty. We show that the uncertainty can be greatly reduced if events are selected in which the transverse momenta of the two B-mesons balance each other to some accuracy, that is |p_1T+p_2T|<k₀. This will fix the scale μ_F≃k₀, and will allow the LHCb experiment, in particular, to study the x-behaviour of gluon distribution down to x∼10⁻⁵, at rather low scales, μ∼2 GeV. We evaluate the expected cross sections using, for illustrative purposes, various recent sets of Parton Distribution Functions.