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Related papers: Two-loop Electroweak Corrections to the Top-Quark …

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In the supersymmetric extension of the Standard Model we derive the two-loop QCD corrections to the scalar quark contributions to the electroweak precision observables entering via the rho parameter. A very compact expression is derived for…

High Energy Physics - Phenomenology · Physics 2009-07-09 A. Djouadi , P. Gambino , S. Heinemeyer , W. Hollik , C. Jünger , G. Weiglein

In the Standard Model Effective Field Theory (SMEFT), operators involving the top quark are generally difficult to probe, and can generate sizable loop contributions to the electroweak precision observables, measured by past and future…

High Energy Physics - Phenomenology · Physics 2022-11-09 Yiming Liu , Yuhao Wang , Cen Zhang , Lei Zhang , Jiayin Gu

We find the leading electroweak corrections to the Lagrangians of heavy-quark effective theory and nonrelativistic QCD. These corrections appear in the Wilson coefficients of the two- and four-quark operators and are considered here at…

High Energy Physics - Phenomenology · Physics 2023-06-06 B. Assi , B. A. Kniehl , J. Soto

Theoretical uncertainties affecting electroweak observables are reviewed and the relevance of two-loop electroweak radiative corrections for the precision tests of the Standard Model is discussed.

High Energy Physics - Phenomenology · Physics 2008-02-03 G. Degrassi , S. Fanchiotti , F. Feruglio , P. Gambino , A. Vicini

The dominant electroweak corrections to the production cross sections and partial decay widths of a light Standard-Model Higgs boson, with mass M_H << 2m_t, are due to top-quark loops. By means of a low-energy theorem, we study at the…

High Energy Physics - Phenomenology · Physics 2009-10-30 A. Djouadi , P. Gambino , B. A. Kniehl

We present an analysis of two-loop mixed QCD and electroweak corrections to the decay of the Z boson into light quarks. We find that the naive factorization of QCD and electroweak corrections does not describe correctly the two-loop…

High Energy Physics - Phenomenology · Physics 2009-10-28 Andrzej Czarnecki , Johann H. Kühn

The top-quark mass can be determined with very high precision from a scan of the total $e^+e^-\to b\bar{b}W^+W^-X$ cross section near the top-pair production threshold. We present the full calculation of electroweak and non-resonant…

High Energy Physics - Phenomenology · Physics 2017-11-03 Martin Beneke , Andreas Maier , Thomas Rauh , Pedro Ruiz-Femenía

We present the first calculation of the two-loop electroweak fermionic correction to the flavour-dependent effective weak-mixing angle for bottom quarks, sin^2 theta_{eff}^{b anti-b}. For the evaluation of the missing two-loop vertex…

High Energy Physics - Phenomenology · Physics 2010-04-21 M. Awramik , M. Czakon , A. Freitas , B. A. Kniehl

Within the framework of the MSSM, we compute the electroweak one-loop supersymmetric quantum corrections to the width $\Gamma (t\rightarrow W^{+}\, b)$ of the canonical main decay of the top quark. The results are presented in two on-shell…

High Energy Physics - Phenomenology · Physics 2011-07-18 David Garcia , Ricardo A. Jimenez , Joan SOLA , Wolfgang Hollik

Using the asymptotic-expansion technique, we compute the dominant two-loop electroweak corrections, of O(G_F m_t^2), to production and decay via a pair of photons or gluons of the CP-odd Higgs boson A^0 in a two-Higgs-doublet model with…

High Energy Physics - Phenomenology · Physics 2008-11-26 Joachim Brod , Frank Fugel , Bernd A. Kniehl

We present the complete analytical result for the two-loop logarithmically enhanced contributions to the high energy asymptotic behavior of the vector form factor and the four-fermion cross section in a spontaneously broken SU(2) gauge…

High Energy Physics - Phenomenology · Physics 2010-11-05 Bernd Jantzen , Johann H. Kühn , Alexander A. Penin , Vladimir A. Smirnov

The effective renormalizable theory describing electromagnetic and strong interactions of quarks of five light flavors ($n_f = 5$ QCD$\times$QED) is considered as a low-energy limit of the full Standard Model. Two-loop relation between the…

High Energy Physics - Phenomenology · Physics 2018-12-31 A. V. Bednyakov

We study the relationship between the $\overline{\mathrm{MS}}$ Yukawa coupling and the pole mass for the bottom and top quarks at the two-loop electroweak order ${\cal O}(\alpha^2)$ in the gaugeless limit of the standard model. We also…

High Energy Physics - Phenomenology · Physics 2015-05-06 Bernd A. Kniehl , Oleg L. Veretin

One-loop radiative corrections to the charged Higgs coupling to two fermions and to the charged Higgs fermionic decay are studied. A renormalization scheme is proposed including the definition of the parameter $\tan\beta$ through the…

High Energy Physics - Phenomenology · Physics 2009-08-12 Marco A. Diaz

We compute the two-loop electroweak correction to the production of the Higgs boson in gluon fusion to higher orders in the dimensional-regularization parameter $\epsilon = (d-4)/2$. We employ the method of differential equations to compute…

High Energy Physics - Phenomenology · Physics 2017-03-08 Marco Bonetti , Kirill Melnikov , Lorenzo Tancredi

A novel approach to study electroweak physics at one-loop level in generic ${\rm SU(2)_L \times U(1)_Y}$ theories is introduced. It separates the 1-loop corrections into two pieces: process specific ones from vertex and box contributions,…

High Energy Physics - Phenomenology · Physics 2008-11-26 K. Hagiwara , D. Haidt , C. S. Kim , S. Matsumoto

A review is given on the quantum correction $\Delta r$ in the $W$--$Z$ mass correlation at the electroweak two-loop level, as derived from the calculation of the muon lifetime in the Standard Model. Exact results for $\Delta r$ and the…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. Freitas , S. Heinemeyer , W. Hollik , W. Walter , G. Weiglein

The electroweak contributions to the forward-backward asymmetry in the production of top-quark pairs at the Tevatron are evaluated at O(alpha^2) and O(alpha*alphas^2). We perform a detailed analysis of all partonic channels that produce an…

High Energy Physics - Phenomenology · Physics 2013-05-29 Wolfgang Hollik , Davide Pagani

The leading heavy-top two-loop corrections to the \Zbb~vertex are determined from a direct evaluation of the corresponding Feynman diagrams in the large \Mt~limit. %The calculation is done in the naive %dimensional regularization scheme…

High Energy Physics - Phenomenology · Physics 2009-09-25 A. Denner , W. Hollik , B. Lampe

Two-loop electroweak corrections to the electron, muon, and tau lepton anomalous magnetic moments have been computed recently. Effects of hadronic contributions to the photon propagator in two-loop QED corrections have also been reanalysed.…

High Energy Physics - Phenomenology · Physics 2011-04-15 Andrzej Czarnecki , Bernd Krause