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The corrections induced by a heavy top on the main precision observables are now available up to O(alpha^2 mt^2/mw^2). The new results imply a significant reduction of the theoretical uncertainty and can have a sizable impact on the…

High Energy Physics - Phenomenology · Physics 2011-03-02 Paolo Gambino

Recent calculations of the two-loop electroweak effects enhanced by powers of the top mass have been implemented in the main electroweak libraries and have an important effect on the indirect determination of the Higgs mass MH. I briefly…

High Energy Physics - Phenomenology · Physics 2007-05-23 Paolo Gambino

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

We present the evaluation of the two-loop O(g^4 mt^2) effects in the partial widths of the Z boson in the MSbar scheme and in two different implementations of the on-shell scheme. We observe a clear reduction of the scheme dependence of the…

High Energy Physics - Phenomenology · Physics 2015-06-25 G. Degrassi , P. Gambino

In order to test the accuracy of the Heavy Top-mass Expansion (HTE) employed in recent two-loop calculations of MW and sin^2theta_eff, we consider their contributions to subtracted quantities of the form MW_sub=MW(mh)-MW(mh0), where mh0 is…

High Energy Physics - Phenomenology · Physics 2009-10-31 P. Gambino , A. Sirlin , G. Weiglein

I discuss the importance of the $O(g^4 m_t^2/\mw^2)$ corrections to the effective electroweak angle and Mw in the indirect determination of the Higgs mass. I emphasize the r\^ole of a very precise Mw measurement on the Mh estimate.

High Energy Physics - Phenomenology · Physics 2007-05-23 Giuseppe Degrassi

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

The two-loop O(g^4 mt^2/mw^2) corrections are incorporated in the theoretical calculation of MW, sin^2 theta_MSbar(MZ), and sin^2 theta_eff, as functions of MH. The analysis is carried out in a previously proposed MSbar formulation and two…

High Energy Physics - Phenomenology · Physics 2008-11-26 G. Degrassi , P. Gambino , A. Sirlin

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

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

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

The utility of precision electroweak measurements for predicting the Standard Model Higgs mass via quantum loop effects is discussed. Current constraints from $m_W$ and $\sinsthw\mzms$ imply a relatively light Higgs $\lsim 154$ GeV which is…

High Energy Physics - Phenomenology · Physics 2007-05-23 William J. Marciano

Electroweak precision observables allow stringent tests of the Standard Model at the quantum level and imply interesting bounds on the mass of the Higgs boson through higher-order loop effects. Very significant constraints come especially…

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

A review of the calculation of the leading three-loop electroweak corrections to the rho-parameter, sin^2 theta_eff and the W-boson mass is presented. The heavy Higgs mass expansion and the renormalization are discussed.

High Energy Physics - Phenomenology · Physics 2007-05-23 R. Boughezal , B. Tausk

The two-loop corrections to the electroweak gauge bosons quartic couplings growing quadratically with the Higgs boson mass are calculated in the Standard Model in the limit of large Higgs mass. The corrections to WWWW, WWZZ and ZZZZ…

High Energy Physics - Phenomenology · Physics 2009-10-30 V. Borodulin , G. Jikia

We identify a novel next-to-leading order renormalization effect in the dimension-six SMEFT with direct phenomenological impact. The Higgs-Yukawa operator that modifies the top-Higgs coupling $\kappa_t$ induces a shift in the $ W $ mass at…

High Energy Physics - Phenomenology · Physics 2026-05-01 Lukas Born , Admir Greljo , Anders Eller Thomsen

We discuss the impact of the two-loop corrections to the Higgs mass in the NMSSM beyond $O(\alpha_S(\alpha_b + \alpha_t))$. For this purpose we use the combination of the public tools SARAH and SPheno to include all contributions stemming…

High Energy Physics - Phenomenology · Physics 2015-03-05 Mark D. Goodsell , Kilian Nickel , Florian Staub

The impact of theoretical and experimental uncertainties on the indirect determination of the Higgs boson mass, MH, in the Standard Model (SM) is discussed. Special emphasis is put on the electroweak precision observables MW (the W boson…

High Energy Physics - Phenomenology · Physics 2007-05-23 U. Baur , R. Clare , J. Erler , S. Heinemeyer , D. Wackeroth , G. Weiglein , D. R. Wood

We present an analytical calculation of the leading three-loop radiative correction to the S-parameter in the Standard Model in the large Higgs mass limit. Numerically, S^(3) = 1.1105*g^4/(1024 pi^3)*m_H^4/M_W^4. When combined with the…

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