Higgsstrahlung at NNLL′+NNLO matched to parton showers in GENEVA

Abstract

We present results for the Higgsstrahlung process within the Geneva Monte Carlo framework. We combine the fully differential NNLO calculation with the higher-order resummation in the 0-jettiness resolution variable (beam thrust). The resulting parton-level events are further showered and hadronised by Pythia8. The beam thrust resummation is carried out to NNLL accuracy, which consistently incorporates all singular virtual and real NNLO corrections. It thus provides a natural perturbative connection between the NNLO calculation and the parton shower regime, including a systematic assessment of perturbative uncertainties. In this way, observables which are inclusive over the additional radiation are correct to NNLO, while the description of 0-jet-like resummation variables is improved beyond the parton shower approximation. We provide predictions for the 13 TeV LHC. THEORETICAL FRAMEWORKThe theoretical framework of our calculation is based on the Geneva method, which has been developed in Refs. [23,[28][29][30]. While we report in the following all the necessary ingredients for the specific Higgsstrahlung process under investigation, we refer the interested readers to the original papers where the derivations of the results used here are presented in greater detail.

Higgs decay into massive b-quarks at NNLO QCD in the nested soft-collinear subtraction scheme

“…The impact of the b-quark mass may be sizeable in certain regions of the phase space. Higher-order effects in that process have also been investigated using parton showers [22][23][24]. Another contribution to the Higgs decay width at NNLO is mediated by top-quark loops.…”

New tools and parton shower for Higgs theoretical predictions

“…The method was first tested on jet production in e + e − collisions [8] and later applied to the Drell-Yan process at the LHC [9,10]. More recently, the Higgsstrahlung processes were implemented [11], marking the most complicated final state yet considered. In this section we shall briefly sketch the G method and then show results obtained for the Higgsstrahlung case.…”

“…The rapidity of the hardest lepton and the transverse momentum of the Higgs in Z H production, at various stages in the shower process.Figure fromRef [11]…”

“…The transverse momenta of the Higgs and of the Z H system, at various stages in the shower process and with the gluon fusion channel contributions included. Figure from Ref [11]…”

Bottom quark mass effects in associated WH production with the H→bb¯ decay through NNLO QCD

“…In the context of associated Higgs production, they have been employed in Refs. [30][31][32][33][34][35][36]. For this reason, it is interesting to compare fixed-order and parton-shower results with each other.…”