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

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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

The prediction of the effective electroweak mixing angle $\sin^2\theta_{\rm eff}^{\rm b}$ in the Standard Model at two-loop accuracy has now been completed by the first calculation of the bosonic two-loop corrections to the $Z{\bar b}b$…

High Energy Physics - Phenomenology · Physics 2016-10-04 Ievgen Dubovyk , Ayres Freitas , Janusz Gluza , Tord Riemann , Johann Usovitsch

We introduce techniques to treat numerically Mellin-Barnes integrals in physical regions, which arise in the need of the computation of Feynman integrals for the electroweak two-loop corrections to the pseudo observables at the Z-boson…

High Energy Physics - Phenomenology · Physics 2018-10-11 Johann Usovitsch , Ievgen Dubovyk , Tord Riemann

Recently exact results for the complete electroweak two-loop contributions to the effective weak mixing angle were published. This paper illustrates the techniques used for this computation, in particular the methods for evaluating the loop…

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

Measurements of electroweak precision observables at future electron-positron colliders, such as the CEPC, FCC-ee, and ILC, will be sensitive to physics at multi-TeV scales. To achieve this sensitivity, precise predictions for the Standard…

High Energy Physics - Phenomenology · Physics 2021-04-07 Lisong Chen , Ayres Freitas

The one-loop corrections to the weak mixing angle $\sin^2\theta_{eff}^b$ derived from the $Z{\bar b}b$ vertex, are known since 1985. It took another 30 years to calculate the complete electroweak two-loop corrections to…

High Energy Physics - Phenomenology · Physics 2016-11-08 I. Dubovyk , A. Freitas , J. Gluza , T. Riemann , J. Usovitsch

We present Standard Model predictions for the complete set of phenomenologically relevant electroweak precision pseudo-observables related to the Z-boson: the leptonic and bottom-quark effective weak mixing angles $\sin^2\theta_{\rm…

High Energy Physics - Phenomenology · Physics 2020-01-13 Ievgen Dubovyk , Ayres Freitas , Janusz Gluza , Tord Riemann , Johann Usovitsch

The leading electroweak MSSM two-loop corrections to the electroweak precision observables are calculated. They are obtained by evaluating the two-loop O(\alpha_t^2), O(\alpha_t \alpha_b), O(\alpha_b^2) contributions to the quantity…

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

We present a complete calculation of the contributions to the effective leptonic weak mixing angle, sin^2theta_eff, generated by closed fermion loops at the two-loop level of the electroweak interactions. This quantity is the source of the…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. Awramik , M. Czakon , A. Freitas , G. Weiglein

The complete two-loop electroweak fermionic corrections to the effective leptonic weak mixing angle, sin^2(theta_eff), are now available. Here we shortly present the methods applied and illustrate the implications on indirect prediction for…

High Energy Physics - Phenomenology · Physics 2007-05-23 M. Awramik , M. Czakon , A. Freitas , G. Weiglein

This article presents results for the last unknown two-loop contributions to the $Z$-boson partial widths and $Z$-peak cross-section. These are the so-called bosonic electroweak two-loop corrections, where "bosonic" refers to diagrams…

High Energy Physics - Phenomenology · Physics 2018-06-27 Ievgen Dubovyk , Ayres Freitas , Janusz Gluza , Tord Riemann , Johann Usovitsch

Future electron-position colliders, such as CEPC and FCC-ee, have the capability to dramatically improve the experimental precision for W and Z-boson masses and couplings. This would enable indirect probes of physics beyond the Standard…

High Energy Physics - Phenomenology · Physics 2020-08-26 Lisong Chen , Ayres Freitas

We present the results from a calculation of the full electroweak two-loop fermionic contributions to the effective leptonic mixing angle of the $Z$ boson, $\sin^2\theta_{eff}$, in the Standard Model. On-shell renormalization and analytic…

High Energy Physics - Phenomenology · Physics 2009-11-11 W. Hollik , U. Meier , S. Uccirati

Recently exact results for the complete fermionic two-loop contributions to the prediction for the W-boson mass from muon decay in the electroweak Standard Model have been published [hep-ph/0007091]. This paper illustrates the techniques…

High Energy Physics - Phenomenology · Physics 2009-11-07 A. Freitas , W. Hollik , W. Walter , G. Weiglein

In calculating electroweak radiative corrections at two-loop level, one encounters Feynman graphs with several different masses on the internal propagators and on the external legs, which lead to complicated scalar functions. We describe a…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. Ghinculov , Y. -P. Yao

The Moller experiment and the P2 experiment aim at measuring the weak mixing angle at low scales. The Moller experiment uses $e^- e^- \rightarrow e^- e^-$-scattering, the P2 experiment uses $e^- N \rightarrow e^- N$-scattering. In both…

High Energy Physics - Phenomenology · Physics 2024-07-12 Nico Böttcher , Niklas Schwanemann , Stefan Weinzierl

We provide a compendium of techniques that can be used to compute $O(N_f\alpha^2)$ corrections to low-energy electroweak processes. Specifically, these are the 2-loop electroweak corrections containing a light fermion loop. It is shown that…

High Energy Physics - Phenomenology · Physics 2007-05-23 R. Akhoury , Paresh Malde , Robin G. Stuart

An improved method is presented for the numerical evaluation of multi-loop integrals in dimensional regularization. The technique is based on Mellin-Barnes representations, which have been used earlier to develop algorithms for the…

High Energy Physics - Phenomenology · Physics 2014-11-20 Ayres Freitas , Yi-Cheng Huang

We derive logarithmically enhanced two-loop virtual electroweak corrections for arbitrary fermion-scattering processes at the TeV scale. This extends results previously obtained for massless fermion scattering to processes that involve also…

High Energy Physics - Phenomenology · Physics 2009-11-19 Ansgar Denner , Bernd Jantzen , Stefano Pozzorini

Some methods for the numerical computation of two-loop non-infrared vertices are reviewed. A new method is also proposed and compared to the old ones. Finally, some preliminary results are presented, concerning the evaluation of the…

High Energy Physics - Phenomenology · Physics 2007-05-23 Sandro Uccirati
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