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We calculate the alpha_s virtual corrections to the decay width for b --> s gluon in the standard model. Also the corresponding order alpha_s bremsstrahlung corrections are systematically calculated in this paper. The combined result is…

High Energy Physics - Phenomenology · Physics 2011-01-05 C. Greub , P. Liniger

We calculate the $O(\a_s)$ virtual corrections to the matrix element for $b \to s \gamma$, taking into account the contributions of the four-Fermi operator $O_2$ and the electromagnetic and color dipole-type operators. The results are…

High Energy Physics - Phenomenology · Physics 2011-01-05 C. Greub , T. Hurth , D. Wyler

We present a new determination of the $B_s$ leptonic decay constant from lattice QCD simulations that use gluon configurations from MILC and a highly improved discretization of the relativistic quark action for both valence quarks. Our…

High Energy Physics - Lattice · Physics 2015-05-30 C. McNeile , C. T. H. Davies , E. Follana , K. Hornbostel , G. P. Lepage

Close to the continuum limit, lattice QCD with mass-degenerate Wilson quarks can be described by Symanzik's effective continuum action, which contains the dimension 5 operator, $m\,{\rm tr}(F_{\mu\nu}F_{\mu\nu})$. Its effect can be…

High Energy Physics - Lattice · Physics 2024-01-12 Mattia Dalla Brida , Roman Höllwieser , Francesco Knechtli , Tomasz Korzec , Alberto Ramos , Stefan Sint , Rainer Sommer

We have calculated the decay constants of B and $D$ mesons with lattice QCD. We use an $O(a)$ improved action that takes light quark actions as a starting point, tuned so that it can be directly applied at the physical masses of the $b$ and…

High Energy Physics - Phenomenology · Physics 2010-11-19 Aida X. El-Khadra , Andreas S. Kronfeld , Paul B. Mackenzie , Sinead M. Ryan , James N. Simone

In this article, we calculate the $B_c^* \to B_c$ electromagnetic form-factor with the three-point QCD sum rules, then study the radiative decays $ B_c^{*\pm} \to B_c^{\pm} \gamma$. Experimentally, we can study the radiative transitions…

High Energy Physics - Phenomenology · Physics 2013-09-09 Zhi-Gang Wang

In this contribution we describe a recent study focused on the lattice calculation of inclusive decay rates of heavy mesons. We show how the inclusive calculation can be achieved starting from four-point lattice correlation functions…

We present an estimate of perturbative QCD corrections to the decay $Z \to Wu\bar d$. A simple approximate approach is described in detail. The difference of masses of $M_Z$ and $M_W$ is used as an expansion parameter. A complete analytical…

High Energy Physics - Phenomenology · Physics 2016-08-24 Andrzej Czarnecki , Kirill Melnikov

We calculate next to leading order QCD corrections to the direct decays b -> J/Psi + X and b -> eta_c + X. The strong renormalization scale dependence is seen to persist also in this order and in fact the rate is driven to an unphysical…

High Energy Physics - Phenomenology · Physics 2010-11-01 L. Bergstrom , P. Ernstrom

We provide a systematic treatment of the previously discovered power-enhanced QED corrections to the leptonic decay $B_q\to \mu^+\mu^-$ ($q = d, s$) in the framework of soft-collinear effective theory (SCET). Employing two-step matching on…

High Energy Physics - Phenomenology · Physics 2022-11-22 Martin Beneke , Christoph Bobeth , Robert Szafron

We discuss the B-meson light-cone wavefunction relevant for QCD factorization approach for exclusive B-meson decays. We derive the operator product expansion for the B-meson light-cone wavefunction, taking into account the local composite…

High Energy Physics - Phenomenology · Physics 2008-11-26 Hiroyuki Kawamura , Jiro Kodaira , Kazuhiro Tanaka

Recent advances in the QCD corrections to $b\to s\gamma$ decay in the MSSM include i.) evaluation of the relevant operators, Wilson coefficients and anomalous dimension matrix elements for the various MSSM effective theories valid at scales…

High Energy Physics - Phenomenology · Physics 2011-01-27 Howard Baer , Michal Brhlik

We compute next-to-next-to-leading order QCD corrections to the partonic processes $b\to c \bar{u} d$ and $b\to c \bar{c} s$, which constitute the dominant decay channels in standard model predictions for $B$-meson lifetimes within the…

High Energy Physics - Phenomenology · Physics 2024-07-11 Manuel Egner , Matteo Fael , Kay Schönwald , Matthias Steinhauser

The leptonic radiative decay $B \to \gamma l\nu$ is of great importance in the determination of $B$ meson wave functions, and evaluating the form factors $ F_{V,A}$ are the essential problem on the study of this channel. We computed…

High Energy Physics - Phenomenology · Physics 2019-01-16 Yue-Long Shen , Zhi-Tian Zou , Yan-Bing Wei

We construct the effective Lagrangian describing QCD in the multi-Regge kinematics. It is obtained from the original QCD Lagrangian by eliminating modes of gluon and quark fields not appearing in this underlying kinematics.

High Energy Physics - Theory · Physics 2009-10-28 R. Kirschner , L. N. Lipatov , L. Szymanowski

The perturbative part of the effective QCD Lagrangian was constructed by the renormalization group approach in the 4-loop approximation. It was extrapolated in the non-perturbative region under the assumption of the existence of gluon…

High Energy Physics - Phenomenology · Physics 2011-04-15 P. A. Kovalenko , L. V. Laperashvili

We investigate two-loop gluino corrections to the effective Lagrangian for $b\to s+\gamma(g)$ in the minimal supersymmetric extension of the standard model (MSSM) at large $\tan\beta$, including the contributions in which quark flavor…

High Energy Physics - Phenomenology · Physics 2009-11-10 Tai-Fu Feng

The Lambda_b to Lambda_c semileptonic decay is analyzed in the framework of heavy quark effective theory to the order of 1/m_c and 1/m_b. The QCD sum rule and large N_c predictions to the decay form factors are applied. It argues that the…

High Energy Physics - Phenomenology · Physics 2011-01-27 Jong-Phil Lee , Chun Liu , H. S. Song

We review the present status of QCD corrections to weak decays beyond the leading logarithmic approximation including particle-antiparticle mixing and rare and CP violating decays. After presenting the basic formalism for these calculations…

High Energy Physics - Phenomenology · Physics 2008-11-26 Gerhard Buchalla , Andrzej J. Buras , Markus E. Lautenbacher

We calculate the Lamb, fine and hyperfine shifts in $b\bar b$ with $n=2$, $l=0,1$. Radiative corrections as well as leading nonperturbative corrections (known to be due to the gluon condensate) are taken into account. The calculation is…

High Energy Physics - Phenomenology · Physics 2009-10-28 S. Titard , F. J. Yndurain