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Related papers: Electroweak two-loop corrections to sin^2{\theta}(…

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The most precise measurement of the weak mixing angle sin^2(theta) at LEP is from the forward-backward asymmetry e+e- --> bbbar at the Z-pole. In this note the QED and electroweak radiative corrections to obtain the pole asymmetry from the…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. Freitas , K. Moenig

The leading electroweak MSSM two-loop corrections to the $\rho$-parameter are calculated. They are obtained by evaluating the two-loop self-energies of the Z and the W boson at O(Gf^2 m_t^4) in the limit of heavy scalar quarks. A very…

High Energy Physics - Phenomenology · Physics 2007-05-23 S. Heinemeyer , G. Weiglein

A combination of algebraical and numerical techniques for calculating two-loop top-quark and Higgs-boson corrections to electroweak precision observables like $\Delta r$ or the $\rho$-parameter is presented. The renormalization is performed…

High Energy Physics - Phenomenology · Physics 2011-03-02 S. Bauberger , G. Weiglein

Recent electroweak two-loop corrections in the Minimal Supersymmetric Standard Model (MSSM) are reviewed. They have been obtained with the help of the programs FeynArts and TwoCalc, making use of the recently completed MSSM model file for…

High Energy Physics - Phenomenology · Physics 2009-11-07 S. Heinemeyer

We present a complete calculation of the next-to-next-to-leading (NNLO) electroweak corrections involving closed fermion loops to the $e^+ e^- \to ZH$ process. This has been achieved by using a semi-numerical technique for the two-loop…

High Energy Physics - Phenomenology · Physics 2023-02-01 Ayres Freitas , Qian Song

We present the electroweak corrections for the production of a photon pair through gluon fusion, focusing on the contribution from the first two generations of quarks. The two-loop amplitude is calculated using a series of projection…

High Energy Physics - Phenomenology · Physics 2025-12-09 Gabriele Fiore , Ciaran Williams

Recently, the calculation of fermionic electroweak two-loop corrections to the total width of the Z boson and hadronic Z-peak cross-section in the Standard Model has been presented in arXiv:1310.2256, where "fermionic" refers to diagrams…

High Energy Physics - Phenomenology · Physics 2020-12-24 A. Freitas

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 evaluation of the two-loop MSSM-contributions to the electroweak precision observables M_W and s_w^eff at order(alpha_t^2), order(alpha_t alpha_b), order(alpha_b^2) is presented. These contributions enter via Delta(rho), and it is…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. Haestier , D. Stöckinger , G. Weiglein , S. Heinemeyer

We calculate the two-loop QCD correction to the scalar quark contributions to the electroweak gauge-boson self-energies at zero momentum-transfer in the supersymmetric extension of the Standard Model. We then derive the $O(\alpha_s)$…

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

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

We compute analytically the complete electroweak two-loop corrections to the $B^0-{\bar B}^0$ mixing. These corrections fix the normalization of the electroweak coupling employed in the extraction of $|V_{td}|$ and reduce the theoretical…

High Energy Physics - Phenomenology · Physics 2009-10-31 P. Gambino , A. Kwiatkowski , N. Pott

Numerical calculation of two-loop electroweak corrections to the muon anomalous magnetic moment ($g$-2) is done based on, on shell renormalization scheme (OS) and free quark model (FQM). The GRACE-FORM system is used to generate Feynman…

High Energy Physics - Phenomenology · Physics 2019-04-17 Tadashi Ishikawa , Nobuya Nakazawa , Yoshiaki Yasui

Processes involving only massless or massive quarks at tree-level get corrections from massive (lighter, heavier, or equal-mass) secondary quarks starting at two-loop order, generated by a virtual gluon splitting into a massive quark…

High Energy Physics - Phenomenology · Physics 2024-05-15 Alejandro Bris , Vicent Mateu

We discuss two-loop leading and angular-dependent next-to-leading logarithmic electroweak virtual corrections to arbitrary processes at energies above the electroweak scale. The relevant Feynman diagrams involving soft-collinear gauge…

High Energy Physics - Phenomenology · Physics 2008-11-26 Ansgar Denner , Michael Melles , Stefano Pozzorini

We present the results for the full electroweak two-loop bosonic contributions to the effective leptonic mixing angle of the $Z$ boson, $\sin^2\theta_{\rm eff}$, in the Standard Model. A method applied to extract collinear divergences from…

High Energy Physics - Phenomenology · Physics 2008-11-26 W. Hollik , U. Meier , S. Uccirati

We compute two-loop electroweak corrections to double Higgs boson production in gluon fusion mediated by light quarks in a fully analytical way. We determine a basis of master integrals satisfying canonical differential equations in…

High Energy Physics - Phenomenology · Physics 2025-06-03 Marco Bonetti , Philipp Rendler , William J. Torres Bobadilla

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

Improved predictions for the Z-boson decay width and the hadronic Z-peak cross-section within the Standard Model are presented, based on a complete calculation of electroweak two-loop corrections with closed fermion loops. Compared to…

High Energy Physics - Phenomenology · Physics 2014-01-24 A. Freitas

We give some details of the recently completed calculation of the full two-loop fermionic corrections to the effective leptonic weak mixing angle. Among others, we describe the C++ library DiaGen/IdSolver, which was used to reduce the…

High Energy Physics - Phenomenology · Physics 2009-11-10 M. Awramik , M. Czakon , A. Freitas , G. Weiglein