Resummation of Hadroproduction Cross-sections at High Energy

TL;DR

This paper revisits high energy resummation techniques for hadroproduction cross-sections, showing that running coupling effects significantly reduce previously observed enhancements and providing numerical estimates for various processes at the LHC.

Contribution

It demonstrates that running coupling effects diminish large fixed-coupling enhancements, offering a new explanation for K-factors in perturbative hadroproduction calculations.

Findings

Resummation effects modify B-production cross-section by up to 15% at the LHC.

Gluonic W-production enhancement can reach 50% at large rapidities.

Running coupling reduces infrared singularity effects compared to fixed coupling.

Abstract

We reconsider the high energy resummation of photoproduction, electroproduction and hadroproduction cross-sections, in the light of recent progress in the resummation of perturbative parton evolution to NLO in logarithms of Q^2 and x. We show in particular that the when the coupling runs the dramatic enhancements seen at fixed coupling, due to infrared singularities in the partonic cross-sections, are substantially reduced, to the extent that they are largely accounted for by the usual NLO and NNLO perturbative corrections. This leads to a novel explanation of the large K-factors commonly found in perturbative calculations of hadroproduction cross-sections. We give numerical estimates of high energy resummation effects for inclusive B-production, inclusive jets, Drell-Yan and vector boson production, along with their rapidity distributions. We find that resummation modifies the B-production cross-section at the LHC by at most 15%, but that the enhancement of gluonic W-production may be as large as 50% at large rapidities.