相关论文: Comparing B -> X_u l nu_l to B -> X_s gamma

Measuring the photon energy spectrum in radiative B decays provides essential help for gaining theoretical control over semileptonic B transitions. The hadronic recoil mass distribution in B -> X_u \ell\nu promises the best environment for…

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…

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…

I first introduce the importance of measuring V_ub precisely. Then, from a theoretician's point of view, I review (a) past history, (b) present trials, and (c) possible future alternatives on measuring |V_ub| and/or |V_ub/V_cb|. As of my…

We propose the determination of the CKM matrix element $|V_{ub}|$ by the measurement of the spectrum of $B \to D_s^+ X_u$, dominated by the spectator quark model mechanism $\bar{b} \to D_s^{(*)+} \bar{u}$. The interest of considering $B \to…

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…

We report recent measurements from CLEO of the first two moments of the photon energy spectrum for b -> s gamma decays and the hadronic recoil mass in B -> X_c l nu. These physical quantities allow one to fix non-perturbative parameters…

Moments of the photon energy spectrum in B -> Xs gamma decays, of the hadronic mass spectrum and of the lepton energy spectrum in B -> Xc l nu decays are sensitive to the masses of the heavy quarks as well as to the non-perturbative…

We present an analysis of the Belle measured moments of the lepton energy and hadronic mass spectra in B -> X_c l nu decays and the photon energy spectrum in B -> X_s gamma decays using theoretical expressions derived in the 1S and kinetic…

The photon spectrum in B -> X_s gamma decay, where X_s is any strange hadronic state, is studied using a data sample of 88.5 million e+e- -> Upsilon(4S) -> BBbar decays collected by the BaBar experiment at SLAC. The partial branching…

We review the theoretical understanding of the branching ratio and photon-energy spectrum in B -> Xs gamma decays at next-to-leading order in QCD, including consistently the effects of Fermi motion. For the Standard Model, we obtain B(B ->…

The photon spectrum in B->X_{s,d} \gamma decay, where X_s(d) is any strange (non-strange) hadronic state, is studied using data samples of $e^+e^- \rightarrow \Upsilon(4S) \to B B-bar decays collected by the Babar and Belle experiments.…

Using the previous Belle measurement of the inclusive photon energy in $B\to X_s\gamma$ decays, we determine the first and second moments of this spectrum for minimum photon energies in the $B$ meson rest frame ranging from 1.8 to 2.3 GeV.…

In order to extract the Cabibbo-Kobayashi-Maskawa matrix element |V_{ub}| from B -> X_u l anti-nu_l decays, the overwhelming background from B -> X_c l anti-nu_l decays must be reduced by appropriate acceptance cuts. We study the…

We report two novel determinations of |Vub| with reduced model dependence, based on measurements of the mass distribution of the hadronic system in semileptonic B decays. Events are selected by fully reconstructing the decay of one B meson…

The photon energy spectrum in inclusive weak radiative B -> X_s gamma decay is computed to order alpha_s^2 beta_0. This result is used to extract a value for the HQET parameter $\bar\Lambda$ from the average <1-2E_\gamma/m_B>, and a value…

We present ``state-of-the-art'' theoretical expressions for the triple differential B->X_u l^- nu decay rate and for the B->X_s gamma photon spectrum, which incorporate all known contributions and smoothly interpolate between the…

We derive a class of formulae relating moments of B -> Xu l nu to B -> Xs gamma in the shape function region, where m_X^2 ~ m_b Lambda_QCD. We also derive an analogous class of formulae involving the decay B -> Xs l+ l-. These results…

We derive the dominant part of the O(\alpha_s^2) correction to the photon energy spectrum in the inclusive decay B-> X_s+gamma. The detailed knowledge of the spectrum is important for relating the theoretical calculations of the B-> X_s +…

It is argued that the dominant subleading shape-function contributions to the endpoint region of the charged-lepton energy spectrum in B -> X_u l nu decays can be related in a model-independent way to an integral over the B -> X_s gamma…