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One of the most important O($\alpha_s^2$) corrections to the $B \to X_s \gamma$ branching ratio originates from interference of contributions from the current-current and photonic dipole operators. Its value has been estimated using an…

High Energy Physics - Phenomenology · Physics 2017-07-06 Mikolaj Misiak , Abdur Rehman , Matthias Steinhauser

We complete the next-to-next-to-leading order QCD calculation of the branching ratio for B -> X_s l^+ l^- including recent results for the three-loop anomalous dimension matrix and two-loop matrix elements. These new contributions modify…

High Energy Physics - Phenomenology · Physics 2011-10-18 Christoph Bobeth , Paolo Gambino , Martin Gorbahn , Ulrich Haisch

We complete the calculation of the element $\Gamma_{12}^q$ of the decay matrix in $B_q-\bar{B}_q$ mixing, $q=d,s$, to order $\alpha_s$ in the leading power of the Heavy Quark Expansion. To this end we compute one- and two-loop contributions…

High Energy Physics - Phenomenology · Physics 2022-02-28 Marvin Gerlach , Ulrich Nierste , Vladyslav Shtabovenko , Matthias Steinhauser

We present our results for the NNLL virtual corrections to the matrix elements of the operators O_1 and O_2 for the inclusive process b\to s\ell^+\ell^- in the kinematical region q^2>4m_c^2, where q^2 is the invariant mass squared of the…

High Energy Physics - Phenomenology · Physics 2009-05-20 Christoph Greub , Volker Pilipp , Christof Schüpbach

We calculate the leading order corrections to the anti-B --> X(s) gamma decay in the standard model with two large flat universal extra dimensions. We find that the contributions involving the exchange of Kaluza-Klein modes of the physical…

High Energy Physics - Phenomenology · Physics 2008-11-26 Ayres Freitas , Ulrich Haisch

We compute the differential B -> X_s gamma decay width in the Standard Model as a function of the photon energy using Dressed Gluon Exponentiation (DGE). The resummed spectrum is matched with the fixed-order expansion, making use of the…

High Energy Physics - Phenomenology · Physics 2010-10-27 Jeppe R. Andersen , Einan Gardi

We compute next-to-next-to-leading order perturbative corrections to the decay width difference of mass eigenstates and the charge-parity asymmetry $a_{\rm fs}$ in flavour-specific decays of neutral $B$ mesons. In our calculation we take…

High Energy Physics - Phenomenology · Physics 2025-05-30 Marvin Gerlach , Ulrich Nierste , Pascal Reeck , Vladyslav Shtabovenko , Matthias Steinhauser

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

We calculate nonperturbative ${\cal O}(\Lambda^2_{QCD}/m^2_c)$ corrections to the dilepton invariant mass spectrum and the forward-backward charge asymmetry in $B\to X_se^+e^-$ decay using a heavy quark expansion approach. The method has…

High Energy Physics - Phenomenology · Physics 2016-09-06 G. Buchalla , G. Isidori , S. -J. Rey

We compute NNLO (${\cal O}(\alpha_s^2)$) corrections to the hard-scattering kernels entering the QCD factorization formula for $B\to V\gamma$ decays, where $V$ is a light vector meson. We give complete NNLO results for the dipole operators…

High Energy Physics - Phenomenology · Physics 2008-11-26 Ahmed Ali , Ben D. Pecjak , Christoph Greub

We briefly summarize the current status of perturbative calculations at next-to-next-to-leading-order (NNLO) accuracy in the \bar{B}\to X_s\gamma decay rate as well as that of non-perturbative power-corrections.

High Energy Physics - Phenomenology · Physics 2010-11-02 Thorsten Ewerth

We present NNLL results for the double differential decay width dGamma(b -> X_s l+ l-)/(dsh dcos(theta)), where theta is the angle between the momenta of the b-quark and the l+, measured in the rest-frame of the lepton pair. From these…

High Energy Physics - Phenomenology · Physics 2008-11-26 H. M. Asatrian , K. Bieri , C. Greub , A. Hovhannisyan

The $O(\alpha m_t^2/m_w^2)$ and $O(\alpha \alpha_s m_t^2/m_w^2)$ corrections to the partial decay width $\Gamma(Z \rightarrow b + \bar{b})$ are computed using the current algebra formulation of radiative corrections. This framework allows…

High Energy Physics - Phenomenology · Physics 2009-10-22 Giuseppe Degrassi

In this contribution, the recent calculation of next-to-next-to-leading order QCD and next-to-leading order electroweak corrections to the decay $B_s\to \mu^+\mu^-$ is reviewed, and a detailed discussion of the uncertainty of the theory…

High Energy Physics - Phenomenology · Physics 2014-06-27 Matthias Steinhauser

We construct a factorization theorem that allows to systematically include QCD corrections to the contribution of the electromagnetic dipole operator in the effective weak Hamiltonian to the $\bar B_s \to \mu^+\mu^-$ decay amplitude. We…

High Energy Physics - Phenomenology · Physics 2023-02-08 Thorsten Feldmann , Nico Gubernari , Tobias Huber , Nicolas Seitz

We report on the calculation of next-to-next-to-leading order (NNLO) QCD corrections to the width difference $\Delta \Gamma_s$ in the neutral $B$-meson mixing process $B^0_s - \bar{B}^0_s$. These contributions represent an important step in…

High Energy Physics - Phenomenology · Physics 2021-10-26 Vladyslav Shtabovenko

We compute the next-to-next-to-leading order (NNLO) QCD corrections to b \to c l \bar \nu_l decay rate at a fully differential level. Arbitrary cuts on kinematic variables of the decay products can be imposed. Our computation can be used to…

High Energy Physics - Phenomenology · Physics 2014-11-18 Kirill Melnikov

We consider in detail various theoretical uncertainties of the perturbative predictions for the decay width of $H^0\rightarrow b\overline{b}$ process in the region $50\ GeV< M_H\leq 2M_W$. We calculate the order…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. L. Kataev , V. T. Kim

We compute the O(alpha_s) corrections to the Wilson coefficient of the kinetic operator in inclusive semileptonic B decays. Our analytic calculation agrees with reparameterization invariance and with previous numerical results and paves the…

High Energy Physics - Phenomenology · Physics 2021-02-10 Andrea Alberti , Thorsten Ewerth , Paolo Gambino , Soumitra Nandi

We compute 2-loop QCD corrections to the hard coefficient functions which arise in the factorization formula for B -> X_u l nu decays in the shape-function region. Our calculation provides the last missing piece required for a NNLO analysis…

High Energy Physics - Phenomenology · Physics 2009-02-23 Guido Bell