Supersymmetric next-to-next-to-leading order corrections to Higgs boson production in gluon fusion

Abstract

We compute the total cross section for the production of a light CP even Higgs boson within the framework of supersymmetric QCD up to next-to-next-to-leading order. Technical subtleties in connection to the evaluation of three-loop Feynman integrals with many mass scales are discussed in detail and explicit results for the counterterms of the evanescent couplings are provided. The new results are applied to several phenomenological scenarios which are in accordance with the recent discovery at the LHC. In a large part of the still allowed parameter space the K factor of the supersymmetric theory is close to the one of the Standard Model. However, for the case where one of the top squarks is light, a deviation of more than 5% in the next-to-next-to-leading order prediction of the cross section can be observed where at the same time the predicted Higgs boson mass has a value of about 125 GeV.

Towards precise predictions for Higgs-boson production in the MSSM

“…Implementing the existing results for the two-loop contributions to ∆ b [67][68][69], in both the Higgs mass and cross-section calculations, will also reduce the uncertainty in scenarios where the bottom contributions are relevant. Finally, it could be worthwhile to improve the calculation of the gluon-fusion cross section by taking into account the full Higgs-mass dependence of the two-loop squark-gluon 8 contributions [11][12][13]46] -to cover scenarios in which the non-standard Higgs bosons are heavier than the third-generation squarks -and by including the genuine three-loop effects [63,64].…”

“…[62], and an approximate calculation of those contributions, assuming the VHML and specific hierarchies among the superparticle masses, was recently presented in refs. [63,64]. Furthermore, a subset of potentially large tan β-enhanced contributions from diagrams involving sbottomgluino or stop-chargino loops can be resummed in the LO cross section by means of an effective Higgs-bottom coupling [65][66][67][68][69].…”

“…To assess the uncertainty arising from the fact that we neglect the three-loop SUSY contributions to C (2) , we make use of a recent calculation of those contributions in the VHML [63,64]. The calculation is based on an expansion of the relevant Feynman diagrams in terms of certain hierarchies among the different masses, similar to the strategy that was pursued in refs.…”

“…The results of ref. [64] are available in the form of a Mathematica file, which provides the basis for the expansion of C (2) in various hierarchies of the masses mt 1 , mt 2 , mg, m t , and mq, combined with expansions in differences of these masses. Following an algorithm suggested in ref.…”

“…Following an algorithm suggested in ref. [64], these expansions should allow one to derive a numerical approximation for C (2) in any viable MSSM scenario.…”