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The complete 2-loop quantum electrodynamic corrections to the muon lifetime are calculated in the Fermi theory. The exact result for the effects of virtual and real photons, virtual electrons, muons as well as e+e- pair creation is Delta…

High Energy Physics - Phenomenology · Physics 2008-11-26 Timo van Ritbergen , Robin G. Stuart

We analyze the one loop correction to $Z\rightarrow \nu\nu$ decay in framework of Minimal R-symmetric Supersymmetric Standard Model(MRSSM) in detail with normal and inverse neutrino mass orderings, as a function of $\tan\beta$, Dirac mass…

High Energy Physics - Phenomenology · Physics 2019-03-27 Ke-Sheng Sun , Jian-Bin Chen , Xiu-Yi Yang , Hai-Bin Zhang

We present the dominant two-loop electroweak corrections to the partial decay widths to gluon jets and prompt photons of the neutral CP-odd Higgs boson A^0, with mass M_{A^0} < 2 M_W, in the two-Higgs-doublet model for low to intermediate…

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

In the supersymmetric extension of the Standard Model we derive the two-loop QCD corrections to the scalar quark contributions to the electroweak precision observables entering via the rho parameter. A very compact expression is derived for…

High Energy Physics - Phenomenology · Physics 2009-07-09 A. Djouadi , P. Gambino , S. Heinemeyer , W. Hollik , C. Jünger , G. Weiglein

A shape-function independent relation is derived between the partial B->X_u+l+nu decay rate with a cut on P_+=E_X-P_X<Delta and a weighted integral over the normalized B->X_s+gamma photon-energy spectrum. The leading-power contribution to…

High Energy Physics - Phenomenology · Physics 2011-02-01 Bjorn O. Lange , Matthias Neubert , Gil Paz

We present the complete 2-loop renormalization group equations of the supersymmetric standard model. We thus explicitly include the full set of $R $-parity violating couplings, including $\kappa_iL_iH_2$. We use these equations to do a…

High Energy Physics - Phenomenology · Physics 2009-09-25 Herbi Dreiner , Heath Pois

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

The dominant electroweak corrections to the production cross sections and partial decay widths of a light Standard-Model Higgs boson, with mass M_H << 2m_t, are due to top-quark loops. By means of a low-energy theorem, we study at the…

High Energy Physics - Phenomenology · Physics 2009-10-30 A. Djouadi , P. Gambino , B. A. Kniehl

A self-consistent version of the left-right (LR) symmetric model is used to examine tree- as well as one-loop level radiative corrections to the muon decay. It is shown that constraints on the heavy sector of the model parameters are…

High Energy Physics - Phenomenology · Physics 2009-11-07 M. Czakon , J. Gluza , J. Hejczyk

We calculate the two-loop $10 \times 10$ anomalous dimension matrix ${\cal O}(\alpha_s^{2})$ involving current-current operators, QCD penguin operators, and electroweak penguin operators especially relevant for $\Delta S=1$ weak…

High Energy Physics - Phenomenology · Physics 2009-10-22 Andrzej J. Buras , Matthias Jamin , Markus E. Lautenbacher , Peter H. Weisz

We present an analysis of the two-loop amplitude of the muon decay in the Standard Model (SM) using algebraic renormalization techniques. In addition, we discuss a manifestly BRST invariant IR regulator for the photon within the SM.

High Energy Physics - Phenomenology · Physics 2007-05-23 P. A. Grassi , T. Hurth

We present a short comment on resummation of double-logarithmic (DL) contributions to decays of W and Z -bosons into charged fermion pairs. We show that resummation of DL corrections to the Z -boson decay leads to standard Sudakov form…

High Energy Physics - Phenomenology · Physics 2009-11-02 B. I. Ermolaev

Fermion mass matrices generally rotate in generation space under scale changes, which can lead to fermions of different generations transmuting into one another. The effect is examined in detail and its cross-section calculated for $\gamma…

High Energy Physics - Phenomenology · Physics 2007-05-23 S. T. Tsou

If dark matter (DM) is a fermion and its interactions with the standard model particles are mediated by pseudoscalar particles, the tree-level amplitude for the DM-nucleon elastic scattering is suppressed by the momentum transfer in the…

High Energy Physics - Phenomenology · Physics 2019-03-20 Tomohiro Abe , Motoko Fujiwara , Junji Hisano

I provide a calculation at full two-loop order of the complex pole squared mass of the W boson in the Standard Model in the pure MS-bar renormalization scheme, with Goldstone boson mass effects resummed. This approach is an alternative to…

High Energy Physics - Phenomenology · Physics 2015-06-10 Stephen P. Martin

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

We present the one-loop radiative corrections to the muon decay in U(1)$_z$ extensions of the standard model. We compute the mass of the $W$ boson using those corrections and compare it to an approximation of the complete one-loop…

High Energy Physics - Phenomenology · Physics 2023-06-26 Zoltán Péli , Zoltán Trócsányi

The link between the electroweak gauge boson masses and the Fermi constant via the muon lifetime measurement is instrumental for constraining and eventually pinning down new physics. We consider the simplest extension of the Standard Model…

High Energy Physics - Phenomenology · Physics 2015-01-09 D. Lopez-Val , T. Robens

The radiatively-induced splitting of masses in electroweak multiplets is relevant for both collider phenomenology and dark matter. Precision two-loop corrections of $\mathcal{O}$(MeV) to the triplet mass splitting in the wino limit of the…

High Energy Physics - Phenomenology · Physics 2018-04-03 James McKay , Pat Scott

The inclusive radiative decay of the B meson is known to provide strong constraints on many popular extensions of the Standard Model. Such constraints crucially depend on precision of the Standard Model predictions. One of the main…

High Energy Physics - Phenomenology · Physics 2020-02-11 M. Misiak , A. Rehman , M. Steinhauser
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