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Related papers: Subleading Shape-Function Effects and the Extracti…

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The goal of the SIMBA collaboration is to provide a global fit to the available measurements of inclusive B -> X_s gamma and B -> X_u l nu decays. By performing a global fit one is able to simultaneously determine the relevant…

High Energy Physics - Phenomenology · Physics 2013-03-06 Florian U. Bernlochner , Heiko Lacker , Zoltan Ligeti , Iain W. Stewart , Frank J. Tackmann , Kerstin Tackmann

The charged lepton spectrum in semileptonic $B\to X_u \ell\bar\nu$ decay near maximal lepton energy receives important corrections from subleading structure functions that are formally suppressed by powers of $\Lambda_{QCD}/m_b$ but are…

High Energy Physics - Phenomenology · Physics 2014-11-17 Adam K. Leibovich , Zoltan Ligeti , Mark B. Wise

The ratio between the photon spectrum in B -> X_s gamma and the differential semileptonic rate wrt the hadronic variable M_X/E_X is a short-distance quantity calculable in perturbation theory and independent of the Fermi motion of the b…

High Energy Physics - Phenomenology · Physics 2008-11-26 Ugo Aglietti , Marco Ciuchini , Paolo Gambino

The most precise comparison between theory and experiment for the B -> Xs l+ l- rate is in the low q^2 region, but the hadronic uncertainties associated with an experimentally required cut on m_X potentially spoil the search for new physics…

High Energy Physics - Phenomenology · Physics 2014-11-18 Keith S. M. Lee , Zoltan Ligeti , Iain W. Stewart , Frank J. Tackmann

We study inclusive semi-leptonic (B -> X_c \ell \nu) decay using the power counting m_c ~ \sqrt{Lambda_{QCD} m_b}. Assuming this scaling for the charm-quark mass, the decay kinematics can be chosen to access the shape-function region even…

High Energy Physics - Phenomenology · Physics 2009-11-11 H. Boos , Th. Feldmann , T. Mannel , B. D. Pecjak

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

Recent progress in the theoretical description of inclusive B to X_u l nu decays in the shape-function region is reported. Finite moments of the shape function are related to HQET parameters. Event fractions for several experimental cuts…

High Energy Physics - Phenomenology · Physics 2010-11-23 Bjorn O. Lange

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 study radiative corrections to $\bar{B} \to X_c \ell \bar{\nu}_\ell$ decays assuming the power counting $m_c \sim \sqrt{\Lambda_QCD m_b}$ for the charm-quark mass. Concentrating on the shape-function region, we use effective field-theory…

High Energy Physics - Phenomenology · Physics 2008-11-26 H. Boos , Th. Feldmann , T. Mannel , B. D. Pecjak

We investigate the relation between the E_gamma spectrum in B->X_s gamma decay and the P+ spectrum in semileptonic B->X_u l nu decay (P+ is the hadronic energy minus the absolute value of the hadronic three-momentum), which provides in…

High Energy Physics - Phenomenology · Physics 2014-11-18 Andre H. Hoang , Zoltan Ligeti , Michael Luke

The contribution of subleading jet functions to inclusive decay distributions of $B$ mesons are derived from a systematic two-step matching of QCD current correlators onto soft collinear and heavy quark effective theory. Focusing on the…

High Energy Physics - Phenomenology · Physics 2009-07-24 Gil Paz

The inclusive decay B --> X_u l nu is of much interest because of its potential to constrain the CKM element |V_ub|. Experimental cuts required to suppress charm background restrict measurements of this decay to the shape-function region,…

High Energy Physics - Phenomenology · Physics 2009-01-08 H. M. Asatrian , C. Greub , B. D. Pecjak

We investigate the behaviour of the perturbative relation between the photon energy spectrum in B -> Xs gamma and the hadronic P+ spectrum in semileptonic B -> Xu l nu decay at high orders in perturbation theory in the "large-beta_0" limit,…

High Energy Physics - Phenomenology · Physics 2009-09-02 Francisco Campanario , Michael Luke , Saba Zuberi

We compute the differential momentum correlation function for hadrons produced in the decay of $B$-mesons. This measure of hadronic event shapes tests the free $b$-quark decay picture for nonleptonic and semileptonic decays of $B$-mesons.…

High Energy Physics - Phenomenology · Physics 2009-10-22 Michael Luke , Martin J. Savage , Mark B. Wise

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

Measurements of the rates for the hadronic decays B^+- -> pi K can be used to derive information on the weak phase gamma=arg(V_ub^*) in a largely model-independent way. Hadronic uncertainties can be reduced to the level of nonfactorizable…

High Energy Physics - Phenomenology · Physics 2010-11-23 Matthias Neubert

We examine the anomalous dimension matrix appropriate for the phase space restricted B --> X(u) ell anti-nu and B --> X(s) gamma decay spectra to subleading nonperturbative order. The effects of the time ordered products of the HQET…

High Energy Physics - Phenomenology · Physics 2008-11-26 Michael Trott , Alexander R. Williamson

Current errors on |V_{ub}| are dominated by model dependence. For inclusive decays, the model dependence comes from the Fermi motion of the b quark. By combining the endpoint photon and lepton spectra from the inclusive decays B -> X_s…

High Energy Physics - Phenomenology · Physics 2007-05-23 Adam K. Leibovich

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

Based on a new, exact QCD factorization formula for the partial B->X_s+gamma decay rate with a restriction on large photon energy, improved predictions are presented for the partial moments <E_gamma> and <E_gamma^2>-<E_gamma>^2 of the…

High Energy Physics - Phenomenology · Physics 2009-11-11 Matthias Neubert