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The O(alpha^2 mt^2/mw^2) correction to the relation between G_\mu and the vector boson masses is computed in the MSbar scheme, and the results are used to investigate the magnitude of the effect on the theoretical prediction of mw and…

High Energy Physics - Phenomenology · Physics 2009-10-28 G. Degrassi , P. Gambino , A. Vicini

Higher-order results for electroweak precision observables in the Standard Model are analyzed in view of the experimental accuracies achievable at the present and the next generation of colliders, and the indirect prediction of the…

High Energy Physics - Phenomenology · Physics 2009-10-31 S. Heinemeyer , G. Weiglein

The Standard-Model Higgs boson with mass $ M_H >> 2M_Z $ decays almost exclusively to pairs of $W$ and $Z$ bosons. We calculate the dominant two-loop corrections of $ O( G_F^2 M_H^4 )$ to the partial widths of these decays. In the…

High Energy Physics - Phenomenology · Physics 2009-10-28 A. Frink , B. A. Kniehl , D. Kreimer , K. Riesselmann

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

We present a precise analysis of the Higgs mass corrections stemming from vectorlike top partners in supersymmetric models. We reduce the theoretical uncertainty compared to previous studies in the following aspects: (i) including the…

High Energy Physics - Phenomenology · Physics 2015-08-03 Kilian Nickel , Florian Staub

We discuss the experimental and theoretical uncertainties on precision electroweak observables and their relationship to the indirect constraints on the Higgs-boson mass, $\MH$, in the Standard Model (SM). The critical experimental…

We compute the two-loop corrections to the coefficient of the b --> s gamma magnetic penguin present in the limits of heavy top and/or heavy higgs. This kind of corrections affects in a significant way the observables measured at LEP. On…

High Energy Physics - Phenomenology · Physics 2009-10-09 A. Strumia

Higgs decays to gauge boson pairs are a crucial ingredient in the study of Higgs properties, with the decay $H\rightarrow\gamma\gamma$ being particularly sensitive to new physics effects. Assuming all potential new physics occurs at…

High Energy Physics - Phenomenology · Physics 2018-11-26 Sally Dawson , Pier Paolo Giardino

We perform a fit to precise electroweak data to determine the Higgs and top masses. Penalty functions taking into account their production limits are included. We find ${\displaystyle m_H=65^{+245}_{-4}\ GeV}$ and ${\displaystyle…

High Energy Physics - Phenomenology · Physics 2009-10-22 F. del Aguila , M. Martinez , M. Quiros

The calculation of the two-loop corrections to the partial width of an intermediate-mass Higgs boson decaying into a pair of photons is reviewed. The main focus lies on the electroweak (EW) contributions. The sum of the EW corrections…

High Energy Physics - Phenomenology · Physics 2008-11-26 Frank Fugel

The complete set of two-loop electroweak corrections to the decay width of the Higgs boson into two photons is presented. Two-loop contributions involving weak bosons and the top quark are computed in terms of an expansion in the Higgs…

High Energy Physics - Phenomenology · Physics 2010-04-05 Giuseppe Degrassi , Fabio Maltoni

We study the impact of the two-loop electroweak corrections on the production of a Higgs boson via gluon-fusion in proton-proton collisions at LHC energies. We discuss the prescritpion to include the corrections to the hard scattering…

High Energy Physics - Phenomenology · Physics 2007-05-23 U. Aglietti , R. Bonciani , G. Degrassi , A. Vicini

The LEP data and the measurement of $M_W$ confirm the electro weak symmetry breaking by the Higgs mechanism with (2--3)\% accuracy. For the Higgs boson mass, fits to the present data (without the SLD result) give $M_h=121^{+207}_{-118}$ GeV…

High Energy Physics - Phenomenology · Physics 2009-10-28 P. H. Chankowski , S. Pokorski

We analytically calculate the dominant two-loop electroweak correction, of O(G_F^2 m_t^4), to the partial width of the decay of a Higgs boson, with mass M_H << m_t, into a bottom-quark pair, and describe the most important conceptual and…

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

We improve the determination of the Higgs-boson mass in the MSSM with heavy superpartners, by computing the two-loop threshold corrections to the quartic Higgs coupling that involve both the strong and the electroweak gauge couplings.…

High Energy Physics - Phenomenology · Physics 2019-11-15 Emanuele Bagnaschi , Giuseppe Degrassi , Sebastian Paßehr , Pietro Slavich

The effects of loop contributions to the electroweak precision observables and m_h in the MSSM with non-minimal flavour violation (NMFV) are analyzed, including the mixing between third and second generation squarks. The mixing-induced…

High Energy Physics - Phenomenology · Physics 2007-05-23 S. Heinemeyer , W. Hollik , S. Penaranda

The leading corrections to electroweak precision observables in the MSSM with non-minimal flavor violation (NMFV) are calculated and the effects on M_W and sin^2 theta_eff are analyzed. The corrections are obtained by evaluating the full…

High Energy Physics - Phenomenology · Physics 2011-01-27 S. Heinemeyer , W. Hollik , F. Merz , S. Penaranda

If the quadratic divergence of the standard electroweak model and its local variation with mass scale are both assumed to be zero, then a modified one-loop calculation yields m_t = 117 GeV and m_H = 183 GeV. Such a scenario may be the…

High Energy Physics - Phenomenology · Physics 2015-06-25 Ernest Ma

Recent higher-order results for the prediction of the W-boson mass, M_W, within the Standard Model are reviewed and an estimate of the remaining theoretical uncertainties of the electroweak precision observables is given. An updated version…

High Energy Physics - Phenomenology · Physics 2009-11-07 Ayres Freitas , Sven Heinemeyer , Georg Weiglein

If the top is very heavy, m_t >> M_Z, the dominant radiative correction effects in all electroweak precision tests can be exactly characterized in terms of two quantities, the rho-parameter and the GIM violating Z -> b bbar coupling. These…

High Energy Physics - Phenomenology · Physics 2009-10-22 Riccardo Barbieri , Matteo Beccaria , Paolo Ciafaloni , Giuseppe Curci , Andrea Vicere'