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1.
Phys Rev Lett ; 131(17): 179901, 2023 Oct 27.
Article in English | MEDLINE | ID: mdl-37955512

ABSTRACT

This corrects the article DOI: 10.1103/PhysRevLett.127.162002.

2.
Phys Rev Lett ; 127(16): 162002, 2021 Oct 15.
Article in English | MEDLINE | ID: mdl-34723588

ABSTRACT

The impact of the finite top-quark mass on the inclusive Higgs production cross section at higher perturbative orders has been an open question for almost three decades. In this Letter, we report on the computation of this effect at next-to-next-to-leading order QCD. For the purely gluonic channel, it amounts to +0.62% relative to the result obtained in the Higgs effective field theory approximation. The formally subleading partonic channels overcompensate this shift, leading to an overall effect of -0.26% at a pp collider energy of 13 TeV, and -0.1% at 8 TeV. This result eliminates one of the main theoretical uncertainties to inclusive Higgs production cross section at the LHC.

3.
Phys Rev Lett ; 114(22): 221801, 2015 Jun 05.
Article in English | MEDLINE | ID: mdl-26196614

ABSTRACT

Weak radiative decays of the B mesons belong to the most important flavor changing processes that provide constraints on physics at the TeV scale. In the derivation of such constraints, accurate standard model predictions for the inclusive branching ratios play a crucial role. In the current Letter we present an update of these predictions, incorporating all our results for the O(α_{s}^{2}) and lower-order perturbative corrections that have been calculated after 2006. New estimates of nonperturbative effects are taken into account, too. For the CP- and isospin-averaged branching ratios, we find B_{sγ}=(3.36±0.23)×10^{-4} and B_{dγ}=(1.73_{-0.22}^{+0.12})×10^{-5}, for E_{γ}>1.6 GeV. Both results remain in agreement with the current experimental averages. Normalizing their sum to the inclusive semileptonic branching ratio, we obtain R_{γ}≡(B_{sγ}+B_{dγ})/B_{cℓν}=(3.31±0.22)×10^{-3}. A new bound from B_{sγ} on the charged Higgs boson mass in the two-Higgs-doublet-model II reads M_{H^{±}}>480 GeV at 95% C.L.

4.
Phys Rev Lett ; 104(16): 162002, 2010 Apr 23.
Article in English | MEDLINE | ID: mdl-20482042

ABSTRACT

We report the results of a next-to-leading order simulation of top quark pair production in association with two jets. With our inclusive cuts, we show that the corrections with respect to leading order are negative and small, reaching 11%. The error obtained by scale variation is of the same order. Additionally, we reproduce the result of a previous study of top quark pair production in association with a single jet.

5.
Phys Rev Lett ; 98(2): 022002, 2007 Jan 12.
Article in English | MEDLINE | ID: mdl-17358597

ABSTRACT

Combining our results for various O(alpha[s]) corrections to the weak radiative B-meson decay, we are able to present the first estimate of the branching ratio at the next-to-next-to-leading order in QCD. We find B(B[over ]-->X[s]gamma)=(3.15+/-0.23) x 10(-4) for Egamma>1.6 GeV in the B[over ]-meson rest frame. The four types of uncertainties:nonperturbative (5%), parametric (3%), higher-order (3%), and m(c)-interpolation ambiguity (3%) have been added in quadrature to obtain the total error.

6.
Phys Rev Lett ; 97(18): 181601, 2006 Nov 03.
Article in English | MEDLINE | ID: mdl-17155534

ABSTRACT

We confirm by explicit computation the conjectured all-orders iteration of planar maximally supersymmetric N=4 Yang-Mills theory in the nontrivial case of five-point two-loop amplitudes. We compute the required unitarity cuts of the integrand and evaluate the resulting integrals numerically using a Mellin-Barnes representation and the automated package of Czakon [Comput. Phys. Commun. 175, 559 (2006)]. This confirmation of the iteration relation provides further evidence suggesting that N=4 gauge theory is solvable.

7.
Phys Rev Lett ; 93(20): 201805, 2004 Nov 12.
Article in English | MEDLINE | ID: mdl-15600915

ABSTRACT

We present a complete calculation of the contributions to the effective leptonic weak mixing angle, sin((2)theta;(lept)(eff), generated by closed fermion loops at the two-loop level of the electroweak interactions. This quantity is the source of the most stringent bound on the mass M(H) of the standard model Higgs boson. The size of the corrections with respect to known partial results varies between -4 x 10(-5) and -8 x 10(-5) for a realistic range of M(H) from 100 to 300 GeV. This translates into a shift of the predicted (from sin((2)theta;(lept)(eff) alone) central value of M(H) by +19 GeV, to be compared with the shift induced by a recent change in the measured top quark mass which amounts to +36 GeV.

8.
Phys Rev Lett ; 89(24): 241801, 2002 Dec 09.
Article in English | MEDLINE | ID: mdl-12484935

ABSTRACT

The last missing correction to the muon lifetime in the standard model at O(alpha(2)) coming from gauge and Higgs boson loops is presented. The associated contribution to the parameter Deltar in the on-shell scheme ranges from 6x10(-5) to -4x10(-5) for Higgs boson masses from 100 GeV to 1 TeV. This result translates into a shift of the W boson mass which does not exceed +/-1 MeV in the same range and amounts, in particular, to approximately -0.8 MeV for a 115 GeV Higgs boson.

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