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The present status of higher-order results in the electroweak theory is summarised, with particular emphasis on recent two-loop results for the prediction of the W-boson mass in the Standard Model and leading three-loop corrections to the…

High Energy Physics - Phenomenology · Physics 2011-07-19 G. Weiglein

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

Recently, $O(\alpha^3)$ corrections to the muon decay rate and $O(\alpha_s^3)$ to heavy quark decays have been determined by Fael, Sch\"onwald, and Steinhauser. This is the first such perturbative improvement of these important quantities…

High Energy Physics - Phenomenology · Physics 2021-09-13 Michał Czakon , Andrzej Czarnecki , Matthew Dowling

We present the full ${{\cal O}}(\alpha)$ electroweak radiative corrections to associated Higgs top pair production in $e^+e^-$ collisions. We combine these results with a new calculation of the full one-loop QCD corrections. The computation…

High Energy Physics - Phenomenology · Physics 2008-11-26 G. Belanger , F. Boudjema , J. Fujimoto , T. Ishikawa , T. Kaneko , K. Kato , Y. Shimizu , Y. Yasui

The associated production of a Higgs boson with a top-antitop quark pair is a crucial process at the LHC since it allows for a direct measurement of the top-quark Yukawa coupling. We present the computation of the radiative corrections to…

High Energy Physics - Phenomenology · Physics 2023-03-29 Stefano Catani , Simone Devoto , Massimiliano Grazzini , Stefan Kallweit , Javier Mazzitelli , Chiara Savoini

The presently most accurate prediction for the W-boson mass in the Standard Model is obtained by combining the complete two-loop result with the known higher-order QCD and electroweak corrections. The numerical impact of the different…

High Energy Physics - Phenomenology · Physics 2021-11-09 M. Awramik , M. Czakon , A. Freitas , G. Weiglein

The neutralino pair annihilation into two photons in our galactic halo gives a robust dark matter signal, since it would give a quasi-monotonic gamma ray. This process is radiatively-induced, and the full-one loop calculation was done…

High Energy Physics - Phenomenology · Physics 2009-11-07 Junji Hisano , Sh. Matsumoto , Mihoko M. Nojiri

We present a complete analysis of the Heavy Quark Effective Theory Lagrangian at order $1/m^2$ in the leading logarithmic approximation, including effects induced by spectator quarks. At this order new correction terms appear in the…

High Energy Physics - Phenomenology · Physics 2009-10-28 B. Blok , J. G. Körner , D. Pirjol , J. C. Rojas

Determinations of alpha_s are reviewed. Current results are limited to a precision of around 3-20%, largely by theoretical uncertainties. All measurements are consistent with a `world average' value of 0.118 +- 0.005 and there is no…

High Energy Physics - Experiment · Physics 2011-07-19 P. N. Burrows

Results are presented for the momentum dependent two-loop contributions of O(alpha_t alpha_s) to the masses and mixing effects in the Higgs sector of the MSSM. They are obtained in the Feynman-diagrammatic approach using a mixed…

High Energy Physics - Phenomenology · Physics 2014-09-25 S. Borowka , T. Hahn , S. Heinemeyer , G. Heinrich , W. Hollik

This talk discusses and explains the two-loop corrections, also known as the Milan factor, for power corrections to jet-shape observables.

High Energy Physics - Phenomenology · Physics 2007-05-23 G. P. Salam

The calculation of the two-loop corrections to the electroweak gauge boson quartic couplings, growing quadratically with the Higgs boson mass, is reviewed. The potential of the CERN Large Hadron Collider and e+e- linear collider to study…

High Energy Physics - Phenomenology · Physics 2007-05-23 G. Jikia

We review the salient features of next-to-leading-order QCD and electroweak corrections to the scattering of two and the production of three weak gauge bosons at the Large Hadron Collider. Results for the tower of $O(\alpha_s^m\alpha^n)$…

High Energy Physics - Phenomenology · Physics 2026-04-21 S. Dittmaier

A simple procedure to estimate O(alpha_s^3) and O(alpha_s^4) corrections to mass-dependent observables is conjectured. The method is tested in a number of cases where the O(alpha_s^3) contribution is exactly known, and reasonable agreement…

High Energy Physics - Phenomenology · Physics 2009-10-30 K. G. Chetyrkin , B. A. Kniehl , A. Sirlin

We evaluate the two-loop ${\cal O}(\alpha_sG_Fm_t^2)$ correction to the $ZZH$ coupling in the Standard Model by means of a low-energy theorem, assuming that the top quark is much heavier than the Higgs boson. We then construct a…

High Energy Physics - Phenomenology · Physics 2016-09-01 Bernd A. Kniehl , Michael Spira

We report on recent results obtained for the massive operator matrix elements which contribute to the massive Wilson coefficients in deep-inelastic scattering for $Q^2 \gg m_i^2$ in case of sub-processes with two fermion lines and different…

High Energy Physics - Phenomenology · Physics 2011-06-30 J. Ablinger , J. Blümlein , S. Klein , C. Schneider , F. Wissbrock

We analyze the minimal supersymmetric Higgs self-couplings at O(alpha_t alpha_s) within the effective potential approach. The two-loop corrections turn out to be of moderate size in the DRbar scheme if the central scale is chosen as half…

High Energy Physics - Phenomenology · Physics 2014-12-24 Mathias Brucherseifer , Ryan Gavin , Michael Spira

Higher-order corrections to the MSSM Higgs-boson masses are desirable for accurate predictions currently testable at the LHC. By comparing the prediction with the measured value of the discovered Higgs signal, viable parameter regions can…

High Energy Physics - Phenomenology · Physics 2020-12-11 Sophia Borowka , Sebastian Paßehr , Georg Weiglein

We present the dominant two-loop electroweak corrections to the partial decay widths to gluon jets and prompt photons of the neutral CP-odd Higgs boson A^0, with mass M_{A^0} < 2 M_W, in the two-Higgs-doublet model for low to intermediate…

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

We present several advances in the effective field theory calculation of the Higgs mass in MSSM scenarios with heavy superparticles. In particular, we compute the dominant two-loop threshold corrections to the quartic Higgs coupling for…

High Energy Physics - Phenomenology · Physics 2017-06-28 Emanuele Bagnaschi , Javier Pardo Vega , Pietro Slavich