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Related papers: Two-Loop O(alpha_s G_F M_Q^2) Heavy-Quark Correcti…

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The electroweak corrections of order ${\cal O}(\alpha_{\rm em} m^2_{t,b}/m^2_w)$ and ${\cal O}(\alpha_{\rm em} m^3_{t,b}/m^3_w)$ to Higgs boson associated production with top quark pair are calculated at $e^+e^-$ colliders in the standard…

High Energy Physics - Phenomenology · Physics 2007-05-23 Xiao-Hong Wu , Chong Sheng Li , Jian Jun Liu

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

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

By means of a heavy-top-quark effective Lagrangian, we calculate the three-loop corrections of O(alpha_s^2 G_F M_t^2) to the H->bb-bar partial decay width of the standard-model Higgs boson with intermediate mass M_H<<2M_t. We take advantage…

High Energy Physics - Phenomenology · Physics 2009-10-30 K. G. Chetyrkin , B. A. Kniehl , M. Steinhauser

The non-decoupling effects of heavy Higgs bosons on the process $e^+e^- \to W^+_LW^-_L$ are discussed in the two Higgs-doublet model. The one-loop corrections to the cross section are calculated by using the equivalence theorem and the…

High Energy Physics - Phenomenology · Physics 2009-10-30 Shinya Kanemura , Hide-Aki Tohyama

We discuss a recent analysis of a dominant two-loop electroweak correction, of O(G_F M_t^2), to the partial width of the decay of an intermediate-mass Higgs boson into a pair of photons. The asymptotic-expansion technique was used in order…

High Energy Physics - Phenomenology · Physics 2007-05-23 Bernd A. Kniehl

At proton colliders, Higgs particles are dominantly produced in the gluon--gluon fusion mechanism. The Higgs--gluons coupling is mediated by heavy quark loops, and the process can serve to count the number of heavy strongly interacting…

High Energy Physics - Phenomenology · Physics 2011-01-13 A. Djouadi , P. Gambino

In the Minimal Supersymmetric Standard Model (MSSM) we present the corrections to the heavy neutral CP-even Higgs-boson production in the WW-fusion and Higgs-strahlung channel, e+e- -> \bar nu nu H, taking into account all O(\alpha)…

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

Higgs-boson production in association with W or Z bosons, p pbar -> WH/ZH + X, is the most promising discovery channel for a light Standard Model Higgs particle at the Fermilab Tevatron. We present the calculation of the electroweak…

High Energy Physics - Phenomenology · Physics 2009-11-10 M. L. Ciccolini , S. Dittmaier , M. Krämer

We present in analytic form the O(alpha_s^5) correction to the H->gg partial width of the standard-model Higgs boson with intermediate mass M_H<2M_t. Its knowledge is useful because the O(alpha_s^4) correction is sizeable (around 20%). For…

High Energy Physics - Phenomenology · Physics 2016-09-06 P. A. Baikov , K. G. Chetyrkin

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 numerical results on the recently completed $O(\alpha^2)$ initial state corrections to the process $e^+e^- \rightarrow \gamma^*/Z^*$, which is a central process at past and future high energy and high luminsoity colliders for…

High Energy Physics - Phenomenology · Physics 2020-01-08 J. Blümlein , A. De Freitas , C. G. Raab , K. Schönwald

The Higgs low-energy theorem gives a simple and elegant way to estimate the couplings of the Higgs boson to massless gluons and photons induced by loops of heavy particles. We extend this theorem to take into account possible nonlinear…

High Energy Physics - Phenomenology · Physics 2015-03-20 M. Gillioz , R. Grober , C. Grojean , M. Muhlleitner , E. Salvioni

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

With the standard model working well in describing the collider data, the focus is now on determining the standard model parameters as well as for any hint of deviation. In particular, the determination of the couplings of the Higgs boson…

High Energy Physics - Phenomenology · Physics 2021-07-28 Pankaj Agrawal , Biswajit Das

We calculate the full ${\cal O}(\alpha_{ew})$ electroweak corrections to the Higgs pair production process $e^+ e^- \to H H Z$ at an electron-positron linear collider in the standard model, and analyze the dependence of the Born cross…

High Energy Physics - Phenomenology · Physics 2015-06-25 Zhang Ren-You , Ma Wen-Gan , Chen Hui , Sun Yan-Bin , Hou Hong-Sheng

The decay of the Standard Model Higgs boson into four leptons via a virtual W-boson or Z-boson pair is one of the most important decay modes in the Higgs-boson search at the LHC. We present the complete electroweak radiative corrections of…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. Bredenstein , A. Denner , S. Dittmaier , M. M. Weber

We consider the prospects for detecting effects due to the Higgs exchange diagram in high energy mu^+ mu^-$, e^+ e^-, and tau^+ tau^- collisions producing a pair of W bosons. The processes l^+l^- -> W^+W^- (with l=mu,e,tau) are analyzed,…

High Energy Physics - Phenomenology · Physics 2009-07-30 U. Baur , E. Brewer

The processes e+e- -> t tbar/b bbar + Higgs allow to measure the Yukawa couplings between Higgs bosons and heavy quarks in supersymmetric theories. The complete set of next-to-leading order SUSY-QCD corrections to the cross sections of…

High Energy Physics - Phenomenology · Physics 2010-04-05 Petra Häfliger , Michael Spira

We compute the dominant two-loop electroweak correction, of O(G_F M_t^2), to the partial width of the decay of an intermediate-mass Higgs boson into a pair of photons. We use the asymptotic-expansion technique in order to extract the…

High Energy Physics - Phenomenology · Physics 2009-11-10 Frank Fugel , Bernd A. Kniehl , Matthias Steinhauser