Related papers: Theoretical Uncertainties in Gamma_sl(b->u)
We propose a new method for precise determination of |V_{td} / V_{ub}| from the ratios of branching ratios BR(B -> \rho \nu \bar \nu ) / BR(B ->\rho l \nu ) and BR(B -> \pi \nu \bar \nu ) / BR(B -> \pi l \nu ). These ratios depend only on…
A study of the charmless semileptonic decay B0 to pi- l+ nu using a large sample of untagged Upsilon(4S) to B Bbar events collected with the Belle detector at the KEKB asymmetric e+ e- collider is presented. The branching fraction of the…
We present the measurements of the CKM matrix parameters Vub, Vcb and of the B mixing oscillation frequency with the BaBar experiment at the asymmetric B-factory PEPII. Data were collected in the years 2000-2002 and the total available…
The ratio of the CKM quark-mixing matrix elements |Vub|/|Vcb| has been measured using B hadron semileptonic decays. The analysis uses the reconstructed mass M_X of the secondary hadronic system produced in association with an identified…
In this talk some of the theoretical aspects of $b \to s \gamma$ transitions are discussed. The focus is on inclusive decays, since these can be computed more reliably. Topics covered are (1) perturbative QCD corrections, (2)…
In this talk we review the theoretical status of the lifetime ratios of heavy hadrons and of the B-mixing quantities $\Delta M_s$, $\Delta \Gamma_s$ and $\phi_s$. While $\Delta M_s$ and $\Delta \Gamma_s$ suffer from large uncertainties due…
The recent observation by the CLEO Collaboration of the inclusive decay $b\to s\gamma$ with a branching fraction consistent with the expectations of the Standard Model is used to constrain the parameter space of the Left-Right Symmetric…
We present an analysis of exclusive charmless semileptonic B-meson decays based on 377 million BBbar pairs recorded with the BABAR detector at the Upsilon(4S) resonance. We select four event samples corresponding to the decay modes B0 -->…
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…
I review the recent theoretical progress on the study of tree-level semileptonic $b\to c$ decays. After briefly reviewing the latest developments on the exclusive determinations of $|V_{cb}|$, I discuss the hints on lepton flavor…
A detailed compilation of uncertainties in the MSbar bottom quark mass m_b(m_b) obtained from low-n spectral sum rules at order alpha_s^2 is given including charm mass effects and secondary b production. The experimental continuum region…
A sample of 365 fb$^{-1}$ of $e^+e^- \to \Upsilon(4S) \to B\bar{B}$ data collected by the Belle II experiment is used to measure the partial branching fractions of charmless semileptonic $B$ meson decays and determine the magnitude of the…
The extra contributions due to an extra generation of vector-like quarks to the isospin symmetry breaking observable associated with the radiative B->K^* \gamma decay is obtained. It is shown that this additional contribution is sensitive…
Recent advances in the calculation of the $b\to s\gamma$ decay branching ratio are presented in the context of supersymmetric theories. Theoretical accuracy increased by inclusion of the next-to-leading order QCD corrections makes it…
We report a new measurement of the CKM parameter V_ub made with a sample of 9.7 million B B-bar events collected with the CLEO II detector. Using Heavy Quark theory, we combine the observed yield of leptons from semileptonic B decay in the…
The LEP investigation of the Bd and Bs oscillations and of the Cabibbo-Kobayashi-Maskawa matrix element Vub improve the constraints on the other elements of this matrix. From a fit to the experimental data and the theory calculations it is…
We extend the approach based on the light-cone expansion and the heavy quark effective theory to the inclusive semileptonic decay of an unpolarized $b$-flavored hadron. It is applied to calculate the semileptonic decay width of the…
We review the current status of theoretical predictions for mixing quantities and lifetimes in the $B$-sector. In particular, due to the first non-zero measurement of the decay rate difference in the neutral $B_s$-system, $\Delta \Gamma_s/…
Semileptonic ${B}$ meson decays involving low-mass charged leptons ${e}$ or ${\mu}$ are expected to be free of non-Standard Model contributions and therefore play a critical role in determinations of ${\vert V_{ub} \vert}$ and ${\vert…
The Cabibbo-Kobayashi-Maskawa matrix element |V_ub| is not well determined yet. It can be extracted from both inclusive or exclusive decays, like B --> pi (rho) l nu-bar_l. However, the exclusive determination from B --> rho l nu-bar_l, in…