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Related papers: Fermionic NNLL corrections to b -> s \gamma

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We calculate the next-to-leading corrections to the branching ratio of exclusive $B\to K^* \gamma$ decay. The renormalization scale dependence is reduced compared to the leading logarithmic result but there remains a dependence on a cutoff…

High Energy Physics - Phenomenology · Physics 2009-10-31 H. H. Asatryan , H. M. Asatrian , D. Wyler

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

Recent developements in the calculation of the NNLO QCD corrections to the charm quark mass dependent matrix elements in B -> X_s gamma are reported. Special emphasis is put on the new results of the virtual O(alpha_s^2) fermionic…

High Energy Physics - Phenomenology · Physics 2007-12-12 Radja Boughezal

The calculation of partial decay rates in B --> X_u l nu decays at next-to-next-to-leading order (NNLO) in alpha_s and to leading order in 1/m_b is described. New results for the hard function are combined with known results for the jet…

High Energy Physics - Phenomenology · Physics 2008-10-17 Ben D. Pecjak

We calculate the virtual and bremsstrahlung fermionic corrections due to the interference of the electro- and chromomagnetic dipole operators in the inclusive \bar{B}\to X_s\gamma decay at O(\alpha_s^2) and present analytical results for…

High Energy Physics - Phenomenology · Physics 2008-11-26 Thorsten Ewerth

Strengthening constraints on new physics from the B -> X_s gamma branching ratio requires improving accuracy in the measurements and the Standard Model predictions. To match the expected Belle-II accuracy, Next-to-Next-to-Leading Order…

High Energy Physics - Phenomenology · Physics 2020-07-15 M. Misiak , A. Rehman , M. Steinhauser

We present a concise review of the recent theoretical progress concerning the standard model calculation of the inclusive radiative Bbar -> X_s gamma decay. Particular attention is thereby devoted to the calculations of the…

High Energy Physics - Phenomenology · Physics 2007-06-23 Ulrich Haisch

We extend the threshold resummation of the large logarithms $\ln x$ which appear in factorization formulas for exclusive $B$ meson decays, $x$ being a spectator momentum fraction, to the next-to-leading-logarithm (NLL) accuracy. It is shown…

High Energy Physics - Phenomenology · Physics 2021-07-28 Zhi-Qing Zhang , Hsiang-nan Li

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

Recently the two-loop next-to-leading logarithmic (NLL) virtual corrections to arbitrary processes with massless external fermions have been calculated. Within the spontaneously broken electroweak theory the one- and two-loop mass…

High Energy Physics - Phenomenology · Physics 2009-02-16 Bernd Jantzen

We calculate the set of O(alpha_s^2) corrections to the branching ratio and to the photon energy spectrum of the decay process B -> X_s gamma originating from the interference of diagrams involving the electromagnetic dipole operator O_7…

High Energy Physics - Phenomenology · Physics 2014-11-21 H. M. Asatrian , T. Ewerth , A. Ferroglia , C. Greub , G. Ossola

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 review and update the branching ratios for the $B \to (\rho,\omega) \gamma$ decays, calculated in the QCD factorization approach in the next-to-leading order (NLO) in the strong coupling $\alpha_s$ and to leading power in $\Lambda_{\rm…

High Energy Physics - Phenomenology · Physics 2007-05-23 Ahmed Ali , Alexander Parkhomenko

The B -> X_s l+ l- decay rate is known at the next-to-next-to-leading order in QCD. It is proportional to alpha_em (mu)^2 and has a +- 4% scale uncertainty before including the O(alpha_em log(M_W^2/m_b^2)) electromagnetic corrections. We…

High Energy Physics - Phenomenology · Physics 2011-10-13 T. Huber , E. Lunghi , M. Misiak , D. Wyler

We present an independent calculation of that part of the O(\alpha_s^2) contribution to the decay width \Gamma(\bar B -> X_s \gamma) which arises from the self-interference term of the electromagnetic dipole operator O_7. Using a different…

High Energy Physics - Phenomenology · Physics 2011-01-05 H. M. Asatrian , A. Hovhannisyan , V. Poghosyan , T. Ewerth , C. Greub , T. Hurth

We study the impact of next-to-next-to-leading order (NNLO) QCD corrections on partial decay rates in B --> X_u l nu decays, at leading-order in the 1/m_b expansion for shape-function kinematics. These corrections are implemented within a…

High Energy Physics - Phenomenology · Physics 2010-02-11 C. Greub , M. Neubert , B. D. Pecjak

We calculate the O($\alpha_s$) gluon Bremsstrahlung corrections to the inclusive decay $b \rightarrow s \gamma$, involving the full operator basis $\hat O_1$ -- $\hat O_8$. Confirming and extending earlier calculations of Ali and Greub, we…

High Energy Physics - Phenomenology · Physics 2009-10-28 Nicolas Pott

In this paper the next-to-leading order (NLO) corrections to $B_c$ meson exclusive decays to S-wave charmonia and light pseudoscalar or vector mesons, i.e. $\pi$, $K$, $\rho$, and $K^*$, are performed within non-relativistic (NR) QCD…

High Energy Physics - Phenomenology · Physics 2014-02-12 Cong-Feng Qiao , Peng Sun , Deshan Yang , Rui-Lin Zhu

We calculate a class of three-loop Feynman diagrams which contribute to the next-to-next-to-leading logarithmic approximation for the width difference $\Delta\Gamma_{s}$ in the $B_s-\bar{B}_s$ system. The considered diagrams contain a…

High Energy Physics - Phenomenology · Physics 2017-12-15 H. M. Asatrian , Artyom Hovhannisyan , Ulrich Nierste , Arsen Yeghiazaryan

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