QCD transverse-momentum resummation in gluon fusion processes

By S. Catani, M. Grazzini. 2010

166 citations recorded by the source corpus.

Abstract We consider the production of a generic system of non-strongly interacting particles with a high total invariant mass M in hadron collisions. We examine the transverse-momentum ( q T ) distribution of the system in the small- q T region ( q T ≪ M ), and we present a study of the perturbative QCD contributions that are enhanced by powers of large logarithmic terms of the type ln ( M 2 / q T 2 ) . These terms can be resummed to all orders in QCD perturbation theory. The partonic production mechanism of the final-state system can be controlled by quark–antiquark ( q q ¯ ) annihilation and/or by gluon fusion. The resummation formalism for the q q ¯ annihilation subprocess is well established, and it is usually extrapolated to the gluon fusion subprocess. We point out that this naive extrapolation is not correct, and we present the all-order resummation formula for the q T distribution in gluon fusion processes. The gluon fusion resummation formula has a richer structure than the resummation formula in q q ¯ annihilation. The additional structure originates from collinear correlations that are a specific feature of the evolution of the colliding hadrons into gluon partonic states. In the q T cross section at small values of q T , these gluon collinear correlations produce coherent spin correlations between the helicity states of the initial-state gluons and definite azimuthal-angle correlations between the final-state particles of the observed high-mass system.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/0f96466efbbbda33f8e99643f65c30384aa28a1c

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In Nuclear and High Energy Physics

Citations in the corpus

Elements of a theory for multiparton interactions in QCD (2011, background): “In addition, ladder graphs allow the transitions g → δg and q → δg from unpolarized collinear distributions to linearly polarized gluons at high k, as has been observed in the study of single Higgs production in [84, 85].”
Calculation of the transverse parton distribution functions at next-to-next-to-leading order (2014, background): “Note that the gluon TPDF is a Lorentz tensor [27, 29, 38, 39] in the space perpendicular to n and n̄.”
A formalism for the systematic treatment of rapidity logarithms in Quantum Field Theory (2012, methodology): “The authors of [48, 49, 72] who have performed the highest order resummations of the transverse momentum spectrum to date have used the resummation formula given in [44].”
Transverse-momentum resummation: Higgs boson production at the Tevatron and the LHC (2011, background): “To obtain reliable predictions, these logarithmically-enhanced terms have to be systematically resummed to all perturbative orders [23–36].”
Merging H/W/Z + 0 and 1 jet at NLO with no merging scale: a path to parton shower + NNLO matching (2012, background): “[28], which clarifies how to incorporate variables parametrizing the momenta of such particles in the b-space resummation formalism.”