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In most of the mass range encompassed by the limits from the direct search and the electroweak precision tests, the Higgs boson of the standard model preferably decays to bottom quarks. We present, in analytic form, the dominant two-loop…

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

We consider the currents formed by a heavy and a light quark within Quantum Chromodynamics and compute the matching to Heavy Quark Effective Theory to three-loop accuracy. As an application we obtain the third-order perturbative corrections…

High Energy Physics - Phenomenology · Physics 2010-04-30 S. Bekavac , A. G. Grozin , P. Marquard , J. H. Piclum , D. Seidel , M. Steinhauser

We compute the dominant two-loop electroweak correction, of O(G_F M_t^2), to the partial width of the decay of an intermediate-mass Higgs boson into a pair of photons. We use the asymptotic-expansion technique in order to extract the…

High Energy Physics - Phenomenology · Physics 2009-11-10 Frank Fugel , Bernd A. Kniehl , Matthias Steinhauser

We present a determination of a new class of three-loop Feynman diagrams describing heavy-to-light transitions. We apply it to find the O(alpha_s^2) corrections to the top quark decay t -> bW and to the distribution of lepton invariant mass…

High Energy Physics - Phenomenology · Physics 2008-11-26 Ian Blokland , Andrzej Czarnecki , Maciej Slusarczyk , Fyodor Tkachov

We compute the two-loop mixed QCD-Electroweak (QCD-EW) corrections to the production of a Higgs boson and a gluon in gluon fusion. The relevant four-point functions with internal massive propagators are expressed as multiple polylogarithms…

High Energy Physics - Phenomenology · Physics 2020-12-09 Marco Bonetti , Erik Panzer , Vladimir A. Smirnov , Lorenzo Tancredi

The dominant electroweak two-loop corrections to the precision observables M_W and s_w^eff are calculated in the MSSM. They are obtained by evaluating the two-loop Yukawa contributions of O(alpha_t^2), O(alpha_t alpha_b), O(alpha_b^2) to…

High Energy Physics - Phenomenology · Physics 2009-11-11 J. Haestier , S. Heinemeyer , D. Stöckinger , G. Weiglein

We describe the analytic calculation of the master integrals required to compute the two-mass three-loop corrections to the $\rho$ parameter. In particular, we present the calculation of the master integrals for which the corresponding…

High Energy Physics - Phenomenology · Physics 2018-07-17 J. Blümlein , A. De Freitas , M. van Hoeij , E. Imamoglu , P. Marquard , C. Schneider

We revisit the contributions of order $\alpha^2(Z\alpha)^5m$ and $\alpha^2(Z\alpha)E_F$, respectively, to the Lamb shift and to the hyperfine splitting from mixed self-energy-vacuum-polarization diagrams, involving fermionic loop. We use…

High Energy Physics - Phenomenology · Physics 2023-08-16 Petr A. Krachkov , Roman N. Lee

We compute the master integrals that arise in the calculation of the leading penguin amplitudes in non-leptonic B-decays at two-loop order. The application of differential equations in a canonical basis enables us to give analytic results…

High Energy Physics - Phenomenology · Physics 2015-06-23 Guido Bell , Tobias Huber

We perform a dedicated study of the $q \bar{q}$-initiated two-loop electroweak-QCD Drell-Yan scattering amplitude in dimensional regularization schemes for vanishing light quark and lepton masses. For the relative order $\alpha$ and…

High Energy Physics - Phenomenology · Physics 2023-01-11 Matthias Heller , Andreas von Manteuffel , Robert M. Schabinger , Hubert Spiesberger

The electroweak corrections at one-loop level to the process $H\rightarrow t{\bar t}$ are calculated, especially the fresh top mass value announced recently by CDF is concerned. For $M_H < 1. TeV$ where a perturbative calculation is valid,…

High Energy Physics - Phenomenology · Physics 2015-06-25 Xiao-Xi Chen , Wen-Gan Ma , Yao-Yang Liu , La-Zhen Sun , Chao-Hsi Chang

Recent developments in the computation of two-loop master integrals for massive Bhabha scattering are briefly reviewed. We apply a method based on expansions of exact Mellin-Barnes representations and evaluate all planar four-point master…

High Energy Physics - Phenomenology · Physics 2009-11-11 Stefano Actis , Michal Czakon , Janusz Gluza , Tord Riemann

We compute the two-loop corrections of O(alpha_s^2) to the Yukawa couplings in the framework of the Minimal Supersymmetric Standard Model (MSSM). The calculation is performed using the effective Lagrangian approach under the approximation…

High Energy Physics - Phenomenology · Physics 2014-11-21 L. Mihaila , C. Reisser

The production of electroweak $Z$ bosons that decay to neutrinos and recoil against jets with large transverse momentum $p_\perp$ is an important background process to searches for dark matter at the Large Hadron Collider (LHC). To fully…

High Energy Physics - Phenomenology · Physics 2020-06-24 Hjalte Frellesvig , Kirill Kudashkin , Christopher Wever

One- and two-dimensional harmonic polylogarithms, HPLs and GPLs, appear in calculations of multi-loop integrals. We discuss them in the context of analytical solutions for two-loop master integrals in the case of massive Bhabha scattering…

High Energy Physics - Phenomenology · Physics 2009-11-11 M. Czakon , J. Gluza , T. Riemann

We calculate analytically the two-loop triangle integrals entering the $\mathcal{O}(\alpha\alpha_s)$ corrections to the $HZV$ vertex with $V=Z^*,\gamma^*$ using the method of differential equations. Our result provides a prototype to study…

High Energy Physics - Phenomenology · Physics 2019-10-23 Yuxuan Wang , Xiaofeng Xu , Li Lin Yang

Based on the Simplified Differential Equations approach, we present results for the two-loop non-planar hexa-box families of master integrals. We introduce a new approach to obtain the boundary terms and establish a one-dimensional integral…

High Energy Physics - Phenomenology · Physics 2022-05-25 Adam Kardos , Costas G. Papadopoulos , Alexander V. Smirnov , Nikolaos Syrrakos , Christopher Wever

We calculate the three-loop master integrals of Ref. [1] [arXiv:1709.02160] in analytic form. This allows us to present the fermionic contributions to the $\Delta B=2$ Wilson coefficients of the $B$-$\bar B$ decay matrix in…

High Energy Physics - Phenomenology · Physics 2022-07-06 Artyom Hovhannisyan , Ulrich Nierste

We present a set of scalar master integrals (MIs) needed for a complete treatment of massive two-loop corrections to Bhabha scattering in QED, including integrals with arbitrary fermionic loops. The status of analytical solutions for the…

High Energy Physics - Phenomenology · Physics 2009-11-10 M. Czakon , J. Gluza , T. Riemann

We compute all two-loop master integrals which are required for the evaluation of next-to-leading order QCD corrections in Higgs boson production via gluon fusion. Many two-loop amplitudes for 2 -> 1 processes in the Standard Model and…

High Energy Physics - Phenomenology · Physics 2010-10-27 Charalampos Anastasiou , Stefan Beerli , Stefan Bucherer , Alejandro Daleo , Zoltan Kunszt