We study the prediction for the Higgs transverse momentum distribution in gluon fusion and focus on the problem of matching fixed- and all-order perturbative results. The main sources of matching ambiguities on this distribution are investigated by means of a twofold comparison. On the one hand, we present a detailed qualitative and quantitative comparison of two recently introduced algorithms for determining the matching scale [1, 2]. On the other hand, we apply the results of both methods to three widely used approaches for the resummation of logarithmically enhanced contributions at small transverse momenta: the MC@NLO and POWHEG Monte Carlo approaches, and analytic resummation. While the three sets of results are largely compatible in the low-p⊥ region, they exhibit sizable differ- ences at large p⊥. We show that these differences can be significantly reduced by suitable modifications of formally subleading terms in the Monte Carlo implementations. We ap- ply our study to the Standard Model Higgs boson and to the neutral Higgs bosons of the Two-Higgs-Doublet Model for representative scenarios of the parameter space, where the top- and bottom-quark diagrams enter the cross section at different strengths.
|Titolo:||Resummation ambiguities in the Higgs transverse-momentum spectrum in the Standard Model and beyond|
VICINI, ALESSANDRO (Penultimo)
|Parole Chiave:||Higgs Physics; Beyond Standard Model; Resummation; QCD|
|Settore Scientifico Disciplinare:||Settore FIS/02 - Fisica Teorica, Modelli e Metodi Matematici|
|Data di pubblicazione:||gen-2016|
|Digital Object Identifier (DOI):||10.1007/JHEP01(2016)090|
|Appare nelle tipologie:||01 - Articolo su periodico|