Determination of α
                     S using OPAL hadronic event shapes at 
                $\sqrt{s} = 91\mbox{--}209~\mathrm{GeV}$
               and resummed NNLO calculations

We propose a novel idea for probing the Higgs boson couplings through the measurement of hadronic event shape distributions in the decay of the Higgs boson at lepton colliders. The method provides a unique test of the Higgs boson couplings and of QCD effects in the decay of the Higgs boson. It can be used to probe the Yukawa couplings of the light quarks and to further test the mechanism of electroweak symmetry breaking. From a case study for the proposed Circular Electron-Positron Collider, assuming a hypothesis of SM-like theory, light-quark couplings with a strength greater than 9% of the bottom-quark Yukawa coupling in the standard model can be excluded.

Section: Jhep01(2018)038supporting

confidence: 57%

Probing light-quark Yukawa couplings via hadronic event shapes at lepton colliders

Gao

2018

“…This can be briefly compared to previous estimations obtained with Monte Carlo event generator models in similar analyses. Namely, the values 0.001 [67,69] and 0.0005 [71] obtained previously allow us to validate our estimation. We stress that we have not performed any tuning of the adopted hadronization models to the data in order to artificially reduce the related uncertainties.…”

Section: Estimation Of Uncertaintiessupporting

confidence: 75%

“…For instance, in Ref. [69], the χ 2 /ndof for fits with statistical uncertainties only varies for different observables between 0.5 and 60.…”

Section: Fit Proceduresmentioning

confidence: 99%

High precision determination of αs from a global fit of jet rates

Verbytskyi

Banfi

Kardos

et al. 2019

We present state-of-the-art extractions of the strong coupling based on N 3 LO+NNLL accurate predictions for the two-jet rate in the Durham clustering algorithm at e + e − collisions, as well as a simultaneous fit of the two-and three-jet rates taking into account correlations between the two observables. The fits are performed on a large range of data sets collected at LEP and PETRA colliders, with energies spanning from 35 GeV to 207 GeV. Owing to the high accuracy of the predictions used, the perturbative uncertainty is considerably smaller than that due to hadronization. Our best determination at the Z mass is α s (M Z ) = 0.11881 ± 0.00063(exp.) ± 0.00101(hadr.) ± 0.00045(ren.) ± 0.00034(res.), which is in agreement with the latest world average and has a comparable total uncertainty.

“…The antenna functions are derived systematically from physical matrix elements [47][48][49]. This formalism has been applied in the derivation of NNLO corrections to three-jet production in electron-positron annihilation [50][51][52][53][54] and related event shapes [55][56][57][58][59], which were used subsequently in precision determinations of the strong coupling constant [60][61][62][63][64][65][66][67][68][69][70]. The formalism can be extended to include massive fermions [71][72][73][74].…”

Section: Jhep10(2012)047mentioning

confidence: 99%

Antenna subtraction at NNLO with hadronic initial states: double real initial-initial configurations

Gehrmann

Monni

2012

112

Abstract:The antenna subtraction method handles real radiation contributions in higher order corrections to jet observables. The method is based on antenna functions, which encapsulate all unresolved radiation between a pair of hard radiator partons. To apply this method to compute hadron collider observables, initial-initial antenna functions with both radiators in the initial state are required in unintegrated and integrated forms. In view of extending the antenna subtraction method to next-to-next-to-leading order (NNLO) calculations at hadron colliders, we derive the full set of initial-initial double real radiation antenna functions in integrated form.