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Using a combination of the operator product and heavy quark expansions, we resum the leading nonperturbative contributions to the inclusive photon spectrum in $B\to X_s\,\gamma$ decays. The shape of the spectrum is determined by a universal…

High Energy Physics - Phenomenology · Physics 2010-11-01 Matthias Neubert

We present a new phenomenological analysis of the inclusive rare decay $B \to X_s \ell^+\ell^-$. In particular, we present the first calculation of the NNLL contributions due to the leading two-loop matrix elements, evaluated for arbitrary…

High Energy Physics - Phenomenology · Physics 2009-11-10 A. Ghinculov , T. Hurth , G. Isidori , Y. -P. Yao

It is shown that measuring the lepton invariant mass spectrum in inclusive semileptonic B -> X_u l nu decay yields a model independent determination of |V_{ub}|. Unlike the lepton energy and hadronic invariant mass spectra, nonperturbative…

High Energy Physics - Phenomenology · Physics 2010-11-23 Christian W. Bauer , Zoltan Ligeti , Michael Luke

We consider in the soft-collinear effective theory semi-inclusive hadronic B decays, B-> XM, in which an energetic light meson M near the endpoint recoils against an inclusive jet X. We focus on a subset of decays where the spectator quark…

High Energy Physics - Phenomenology · Physics 2008-11-26 Junegone Chay , Chul Kim , Adam K. Leibovich , Jure Zupan

An analytic result for the O(alpha_s corrections to the triple differential B -> X_u l nu decay rate is presented, to leading order in the heavy-quark expansion. This is relevant for computing partially integrated decay distributions with…

High Energy Physics - Phenomenology · Physics 2015-06-25 F. De Fazio , M. Neubert

The inclusive B -> Xs l+ l- decay rate in the large q^2 region (q^2 > m_{\psi'}^2) receives significant nonperturbative corrections. The resulting uncertainties can be drastically reduced by normalizing the rate to the B -> Xu l nu rate…

High Energy Physics - Phenomenology · Physics 2008-11-26 Zoltan Ligeti , Frank J. Tackmann

We present a QCD-based approach to the endpoint region of the lepton spectrum in $\bar B\to X_u\,\ell\,\bar\nu$ decays. We introduce a genuinely nonperturbative form factor, the shape function, which describes the fall-off of the spectrum…

High Energy Physics - Phenomenology · Physics 2010-11-01 Matthias Neubert

We perform factorization of the most general distribution in semileptonic B -> X_u decays and we resum the threshold logarithms to next-to-leading order. From this (triple-differential) distribution, any other distribution is obtained by…

High Energy Physics - Phenomenology · Physics 2009-11-07 U. Aglietti

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 study nonperturbative corrections to the inclusive rare decay B -> X_s l^+ l^- by performing an operator product expansion (OPE) to O(1/m_b^3). The values of the matrix elements entering at this order are unknown and introduce…

High Energy Physics - Phenomenology · Physics 2011-03-23 Christian W. Bauer , Craig N. Burrell

We apply the operator product expansion to resum the leading nonperturbative corrections to the endpoint region of the lepton spectrum in inclusive semileptonic $B\to X_q\,\ell\,\bar\nu$ decays, taking into account a finite quark mass $m_q$…

High Energy Physics - Phenomenology · Physics 2011-07-19 Thomas Mannel , Matthias Neubert

We study the Lambda_QCD/M_B corrections from subleading shape functions in inclusive B-meson decays. We propose a natural and smooth interpolation from the endpoint region to the full phase space, and derive expressions for the triple…

High Energy Physics - Phenomenology · Physics 2014-11-18 Frank J. Tackmann

We present a systematic study of the shape function for inclusive B-meson decays in the heavy-quark limit, which is based on the QCD equations of motion and heavy-quark symmetry, and takes into account the cusp divergence due to radiative…

High Energy Physics - Phenomenology · Physics 2007-05-23 Hiroyuki Kawamura , Jiro Kodaira , Kazuhiro Tanaka

The semileptonic B-> Xu l nu decays allow a pretty clean determination of the CKM matrix element |Vub|. Nevertheless, the presence of weak-annihilation effects near the end-point of the q2 spectrum introduces uncertainties in the inclusive…

High Energy Physics - Phenomenology · Physics 2008-11-26 J. J. Sanz-Cillero

We derive a new parton-like formula, which establishes a simple connection between the electroweak decay rate $\Gamma (\bar B \to X_s\gamma$) and the rate of a free b-quark decay. The main features of our approach are the treatment of the…

High Energy Physics - Phenomenology · Physics 2009-10-31 Y. -Y. Keum , P. Yu. Kulikov , I. M. Narodetskii , H. S. Song

We study nonperturbative corrections up to O(1/m_b^3) in the inclusive rare B decay B -> X_s l^+ l^- by performing an operator product expansion. The values of the matrix elements entering at this order are unknown and introduce…

High Energy Physics - Phenomenology · Physics 2011-01-27 Christian W. Bauer , Craig N. Burrell

In the determination of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$ from inclusive semileptonic $B$-meson decays, moments of the leptonic invariant mass spectrum constitute valuable observables. To evaluate them with sufficient…

High Energy Physics - Phenomenology · Physics 2024-11-21 Mateusz Czaja , Mikołaj Misiak , Abdur Rehman

We demonstrate, by an explicit one-loop calculation, that at leading twist the nonperturbative effects in B -> gamma l nu, B -> gamma gamma and B -> gamma l+ l- radiative decays are contained in a common multiplicative factor…

High Energy Physics - Phenomenology · Physics 2009-10-09 S. Descotes-Genon , C. T. Sachrajda

We derive precise standard model predictions for the dilepton invariant mass and the tau energy distributions in inclusive B -> Xc tau nu decay. We include Lambda_QCD^2/m_b^2 and alpha_s corrections using the 1S short-distance mass scheme,…

High Energy Physics - Phenomenology · Physics 2014-09-05 Zoltan Ligeti , Frank J. Tackmann

We derive factorization theorems for Lambda_QCD/mb power corrections to inclusive B-decays in the endpoint region, where mX^2 ~mb Lambda_QCD. In B-> Xu e nu our results are for the full triply differential rate. A complete enumeration of…

High Energy Physics - Phenomenology · Physics 2011-01-27 Keith S. M. Lee , Iain W. Stewart