Radiative corrections to the semileptonic and hadronic Higgs-boson decays H→WW/ZZ→4 fermions

Abstract

Abstract:The radiative corrections of the strong and electroweak interactions are calculated for the Higgs-boson decays H → WW/ZZ → 4f with semileptonic or hadronic four-fermion final states in next-to-leading order. This calculation is improved by higher-order corrections originating from heavy-Higgs-boson effects and photonic final-state radiation off charged leptons. The W-and Z-boson resonances are treated within the complex-mass scheme, i.e. without any resonance expansion or on-shell approximation. The calculation essentially follows our previous study of purely leptonic final states. The electroweak corrections are similar for all four-fermion final states; for integrated quantities they amount to some per cent and increase with growing Higgs-boson mass M H , reaching 7-8% at M H ∼ 500 GeV. For distributions, the corrections are somewhat larger and, in general, distort the shapes. Among the QCD corrections, which include corrections to interference contributions of the Born diagrams, only the corrections to the squared Born diagrams turn out to be relevant. These contributions can be attributed to the gauge-boson decays, i.e. they approximately amount to α s /π for semileptonic final states and 2α s /π for hadronic final states. The discussed corrections have been implemented in the Monte Carlo event generator Prophecy4f. †

Observation of a new boson with mass near 125 GeV in pp collisions at $ \sqrt{s}=7 $ and 8 TeV

“…For the four-fermion final states the total cross section is scaled by the branching fraction B(H → 4 ) calculated with the prophecy4f program [89,90]. The calculations include NLO QCD and EW corrections, and all interference effects up to NLO [25,26,[89][90][91][92][93][94].…”

“…The calculations include NLO QCD and EW corrections, and all interference effects up to NLO [25,26,[89][90][91][92][93][94]. For all the other final states hdecay [91,92] is used, which includes NLO QCD and NLO EW corrections.…”

Higgs production at the lHC

“…Using an adapted version of the program HDECAY [108] which calculates the partial and total Higgs decay widths including the relevant QCD and electroweak higher order 19 This might not be entirely true in the case of the H → W W and H → ZZ decay channels near the 2MW and 2MZ thresholds where the regularization of the spurious spikes that appear when including one-loop electroweak corrections [100,101], might introduce some ambiguities. Furthermore, for heavy Higgs bosons MH > ∼ 500 GeV, additional corrections to the partial H → W W, ZZ widths from the Higgs self-coupling, λHHH ∝ M 2 H become very large [102][103][104]; these uncertainties mostly cancel in the branching ratios, though (but they will substantially affect the cross sections for Higgs production in the vector boson fusion processes which are related to the H → W W/ZZ partial decay widths).…”

Search for the Standard Model Higgs Boson in the Decay ChannelH→ZZ→4linppCollisions atsChatrchyan1, Khachatryan2, Sirunyan3 et al. 2012Phys. Rev. Lett.921100View full textAdd to dashboardCite

“…The total cross section is scaled by the branching fraction BðH ! 4'Þ calculated with PROPHECY4F which includes NLO QCD and electroweak corrections and all interference effects at NLO [24,[38][39][40][41], in particular, effects specific to the 4e and 4 channels. The SM background contribution from ZZ production via q " q is generated at NLO with POWHEG, while other diboson processes (WW, WZ) are generated with PYTHIA with cross sections rescaled to NLO predictions.…”