Higgs production via gluon fusion in the POWHEG approach in the SM and in the MSSM

E Bagnaschi,P Slavich,G Degrassi,A Vicini

doi:10.1007/jhep02(2012)088

Abstract

Abstract We consider the gluon fusion production cross section of a scalar Higgs boson at NLO QCD in the SM and in the MSSM. We implement the calculation in the POWHEG approach, and match the NLO-QCD results with the PYTHIA and HERWIG QCD parton showers. We discuss a few representative scenarios in the SM and MSSM parameter spaces, with emphasis on the fermion and squark mass effects on the Higgs boson distributions.

Highlights

JHEP02(2012)088 breaking is determined by the ratio of vacuum expectation values of their neutral components, tan β ≡ v2/v1
We identify three regions: i) for sufficiently large tan β and sufficiently small mA the squark contribution is modest, ranging between −10% and +5%; this region roughly coincides with the one in which the total MSSM cross section is dominated by the tan β-enhanced bottom quark contribution, and is larger than the SM cross section; ii) a transition region, where the corrections rapidly become as large as −30%; this region coincides with the one in which the SM and MSSM cross sections are similar to each other; iii) for sufficiently large mA the squark correction is almost constant, ranging between −40% and −30%; this region coincides with the one in which the MSSM cross section is smaller than the corresponding SM cross section
We have presented a new implementation5 in the POWHEG approach of the process of Higgs boson production via gluon fusion in the SM and in the MSSM

Summary

SM results

The current public release of POWHEG [95] contains matrix elements evaluated in the HQET. It gives the user the possibility of rescaling the term B(Φ 1) in eq (2.1) by a normalization factor defined as the ratio between the exact Born contribution where the full dependence from the top and bottom masses is kept into account and the Born contribution evaluated in the HQET. In the following we describe the modifications we have introduced in the code to include the full fermion-mass dependence at the NLO and the effect of the two-loop EW corrections

Modifications in POWHEG

SM: numerical results

MSSM results

MSSM: numerical results

Conclusions