Precision calculations for the Higgs decays H → ZZ/WW → 4 leptons

Bredenstein, A.; Denner, Ansgar; Dittmaier, S.; Weber, Marcus M.

doi:10.1016/j.nuclphysbps.2006.09.104

Cited by 58 publications

(62 citation statements)

References 36 publications

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“…First results of this calculation had already been presented at the RADCOR05 conference [17]. At this conference also progress on an independent calculation of the electromagnetic corrections to H → ZZ → 4 leptons has been reported by Carloni Calame et al [18].…”

Section: Introductionmentioning

confidence: 83%

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

Bredenstein

Denner

Dittmaier

et al. 2007

J. High Energy Phys.

189

176

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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. †

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Section: Introductionmentioning

confidence: 83%

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

Bredenstein

Denner

Dittmaier

et al. 2007

J. High Energy Phys.

189

176

View full text Add to dashboard Cite

show abstract

“…A number of other SM NLO effects also enter into the h → 4 amplitude [39,51,52] at the percent level or, in certain regions of kinematic phase space, up to the ten percent level for the case of (universal) QED corrections from soft and collinear photon emission [53]. Once the sensitivity to the effective couplings in eq.…”

Section: Jhep09(2015)185mentioning

confidence: 99%

“…At this point, when fitting to data, including the various NLO effects is crucial in order to obtain an accurate measurement which requires a precise prediction for the SM. These NLO effects can be computed [51,52], including photon emission [53], thus allowing for a precise prediction for the SM to which to compare data. Once percent level sensitivity is reached, an NLO EFT analysis may also become necessary [54][55][56].…”

Section: Jhep09(2015)185mentioning

confidence: 99%

New opportunities in h → 4ℓ

Chen

Harnik

Vega-Morales

2015

J. High Energ. Phys.

104

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The Higgs decay h → 4 has played an important role in discovering the Higgs and measuring its mass thanks to low background and excellent resolution. Current cuts in this channel have been optimized for Higgs discovery via the dominant tree level ZZ contribution arising from electroweak symmetry breaking. Going forward, one of the primary objectives of this sensitive channel will be to probe other Higgs couplings and search for new physics on top of the tree level ZZ 'background'. Thanks to interference between these small couplings and the large tree level contribution to ZZ, the h → 4 decay is uniquely capable of probing the magnitude and CP phases of the Higgs couplings to γγ and Zγ as well as, to a lesser extent, ZZ couplings arising from higher dimensional operators. With this in mind we examine how much relaxing current cuts can enhance the sensitivity while also accounting for the dominant non-Higgs continuum qq → 4 background. We find the largest enhancement in sensitivity for the hZγ couplings ( 100%) followed by hγγ ( 40%) and less so for the higher dimensional hZZ couplings (a few percent). With these enhancements, we show that couplings of order Standard Model values for hγγ may optimistically be probed by end of Run-II at the LHC while for hZγ perhaps towards the end of a high luminosity LHC. Thus an appropriately optimized h → 4 analysis can complement direct decays of the Higgs to on-shell γγ and Zγ pairs giving a unique opportunity to directly access the CP properties of these couplings.

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“…We also comment that in principal there are NLO contributions to the h → 4 decay processes, but these are expected to be small at ∼ 125 GeV [48,49] and not relevant until higher precision is obtained once larger data sets are gathered. Eventually however, these effects should be included and their implementation into our framework is currently ongoing.…”

Section: Jhep01(2015)125mentioning

confidence: 96%

8D likelihood effective Higgs couplings extraction framework in h → 4ℓ

Chen

Marco

Lykken

et al. 2015

J. High Energ. Phys.

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We present an overview of a comprehensive analysis framework aimed at performing direct extraction of all possible effective Higgs couplings to neutral electroweak gauge bosons in the decay to electrons and muons, the so called 'golden channel'. Our framework is based primarily on a maximum likelihood method constructed from analytic expressions of the fully differential cross sections for h → 4 and for the dominant irreducible qq → 4 background, where 4 = 2e2µ, 4e, 4µ. Detector effects are included by an explicit convolution of these analytic expressions with the appropriate transfer function over all center of mass variables. Utilizing the full set of observables, we construct an unbinned detector-level likelihood which is continuous in the effective couplings. We consider possible ZZ, Zγ, and γγ couplings simultaneously, allowing for general CP odd/even admixtures. A broad overview is given of how the convolution is performed and we discuss the principles and theoretical basis of the framework. This framework can be used in a variety of ways to study Higgs couplings in the golden channel using data obtained at the LHC and other future colliders.

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Precision calculations for the Higgs decays H → ZZ/WW → 4 leptons

Cited by 58 publications

References 36 publications

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

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

New opportunities in h → 4ℓ

8D likelihood effective Higgs couplings extraction framework in h → 4ℓ

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