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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

In supersymmetric models with minimal particle content and without left-right squark mixing, the conventional wisdom is that the 125.6 GeV Higgs boson mass implies top squark masses of O(10) TeV, far beyond the reach of colliders. This…

High Energy Physics - Phenomenology · Physics 2013-10-02 Jonathan L. Feng , Philipp Kant , Stefano Profumo , David Sanford

We have examined the electroweak radiative corrections in the LEP precision data in view of the new measurements of $M_W$ and $m_t$ as well as the recent progress in the higher order radiative corrections. From the minimal $\chi^2$-fit to…

High Energy Physics - Phenomenology · Physics 2007-05-23 Kyungsik Kang , Sin Kyu Kang

We present the dominant two-loop ${\rm O}\left(G_F^2M_H^4\right)$ electroweak corrections to the fermi\-onic decay widths of a high-mass Higgs boson in the Standard Model. The corrections are negative and quite significant, and are larger…

High Energy Physics - Phenomenology · Physics 2009-09-25 Loyal Durand , Bernd Kniehl , Kurt Riesselmann

We present an analytical calculation of the leading three-loop radiative correction to the rho-parameter in the Standard Model in the large Higgs mass limit. This correction, of order g^6 m_H^4/M_W^4, is opposite in sign to the leading…

High Energy Physics - Phenomenology · Physics 2010-04-05 R. Boughezal , J. B. Tausk , J. J. van der Bij

Using an effective potential approach, we compute two-loop radiative corrections to the MSSM lightest ${\cal CP}$-even Higgs boson mass $M_{h^0}$ to ${\cal O}(\alpha_t^2)$ for arbitrary left-right top-squark mixing and $\tan\beta$. We find…

High Energy Physics - Phenomenology · Physics 2011-01-13 Jose Ramon Espinosa , Ren-Jie Zhang

We calculate a two-loop effective potential to the order of {\cal O}(\lambda_t^2\alpha_s) in the MSSM. We then study the corresponding two-loop corrections to the CP-even Higgs-boson mass for arbitrary \tan\beta and left-right top-squark…

High Energy Physics - Phenomenology · Physics 2009-10-31 Ren-Jie Zhang

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

We consider for the first time the leading large top mass corrections, arising at higher order in electroweak interactions, to the rare decays $K\to\pi\nu\bar\nu$ and the related modes $B\to X_s\nu\bar\nu$ and $B\to l^+l^-$. Higher order…

High Energy Physics - Phenomenology · Physics 2009-10-09 Gerhard Buchalla , Andrzej J. Buras

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 bosonic contributions to the effective weak mixing angle, $\seff$, at the two-loop level in the electroweak interactions. We find their size to be about three times smaller than inferred from simple estimates from…

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

An updated fit to the precision electroweak data and to the direct measurement of the top quark mass $m_t$ provides significant constraints on $m_t$ and on the Higgs boson mass $M_H$: $m_t/\text{GeV}=172\pm 6$ and…

High Energy Physics - Phenomenology · Physics 2008-11-26 John Ellis , G. L. Fogli , E. Lisi

In these proceedings, we summarise our recent calculations of next-to-leading order electroweak corrections to Higgs boson pair and Higgs boson plus jet production. The calculations are divided into different regions. In the high-energy…

High Energy Physics - Phenomenology · Physics 2023-10-24 Hantian Zhang

In this talk the Higgs boson effects in electroweak precision observables are reviewed and the possibility of indirect information on the Higgs mass from electroweak radiative corrections and precision data is discussed.

High Energy Physics - Phenomenology · Physics 2008-02-03 W. Hollik

We review the theoretical status and the future perspectives of the most important electroweak precision observables in the MSSM. This comprises the mass of the W boson, M_W, the effective leptonic mixing angle, sin^2(theta_eff), the mass…

High Energy Physics - Phenomenology · Physics 2009-11-10 S. Heinemeyer

Recent results of two-loop contributions to the muon (g-2) in the Standard Model and its supersymmetric extension are presented. In the SM the EW contributions are fixed according to the Higgs boson mass measured at LHC. In the MSSM we…

High Energy Physics - Phenomenology · Physics 2014-07-29 Helvecio G. Fargnoli , Christoph Gnendiger , Sebastian Paßehr , Dominik Stöckinger , Hyejung Stöckinger-Kim

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

New heavy particles in an SU(2)_L multiplet, sometimes introduced in extensions of the standard model, have highly degenerate tree-level mass M if their couplings to the Higgs bosons are very small or forbidden. However, loop corrections…

High Energy Physics - Phenomenology · Physics 2009-12-22 Youichi Yamada

We compute the two-loop QCD corrections to the neutral Higgs-boson masses in the MSSM, including the effect of non-vanishing external momenta in the self-energies. We obtain corrections of O(alpha_t*alpha_s) and O(alpha*alpha_s), i.e., all…

High Energy Physics - Phenomenology · Physics 2015-06-23 G. Degrassi , S. Di Vita , P. Slavich

The Minimal Supersymmetric extension of the Standard Model (MSSM) predicts the existence of a light neutral Higgs boson. Once found at the LHC, its mass will immediately become a precision observable. The theoretical value of the Higgs mass…

High Energy Physics - Phenomenology · Physics 2014-11-21 Philipp Kant