Semi-inclusive nonleptonic decays B\to D_s^{(*)} X

We calculate the total and differential decay rates for the semi-inclusive nonleptonic decays $B\to D_s^{(*)} X_q$ ($q=c$ or $u$) under the factorization hypothesis. The initial bound state effect is treated using the light-cone expansion and the heavy quark effective theory. We investigate the contribution of the penguin amplitude for the decay mode $B\to D_s^{(*)} X_c$ and find that it is small but non-negligible. The resulting decay rates for $B\to D_s^{(*)} X_c$ agree with the measurements. The use of the decay mode $B\to D_s^{(*)} X_u$ to determine $|V_{ub}|$ is discussed.Comment: 16 pages, LaTex with 4 figure

B -> K(K^*)X: Decay Distributions, Branching Ratios and CP Asymmetries

We discuss an improved theoretical description of the semi-inclusive B meson decays $B\to K(K^*)X$. The decay distributions are calculated. Their branching ratios are found to be appreciable. The CP asymmetries in the neutral B modes $\bar{B^0}\to K^-(K^{*-})X$ are sizable. An observation of direct CP violation and a measurement of $\gamma$ may come from these neutral B modes.Comment: 4 pages, 9 ps figures, Proceedings of the 4th International Workshop on B Physics & CP Violation (BCP4), Ise-Shima, Japan, February 19-23, 200

Model-independent determination of |V_{ub}|

The decay distribution of the kinematic variable \xi_u in inclusive charmless semileptonic decays of B mesons is unique. The novel method for a model-independent determination of |V_{ub}| is described.Comment: 5 pages, presented at the 3rd International Conference on B Physics and CP Violation, Taipei, Taiwan, 3-7 Dec 199

Determining |V_{ub}| from the sum rule for semileptonic B decay

A precise determination of |V_{ub}| can be obtained exploiting the sum rule for inclusive charmless semileptonic B-meson decays. The sum rule is derived on the basis of light-cone expansion and b-flavored quantum number conservation. The sum rule does not receive any perturbative QCD correction. In this determination of |V_{ub}|, there is no perturbative QCD uncertainty, while the dominant hadronic uncertainty is avoided. Moreover, this method is not only theoretically quite clean, but experimentally also very efficient in the discrimination between B\to X_u\ell\nu signal and B\to X_c\ell\nu background. The sum rule requires measuring the lepton pair spectrum. We analyze the lepton pair spectrum, including the leading perturbative and nonperturbative QCD corrections.Comment: 15 pages, 5 Postscript figures, analysis of the weighted spectrum expanded, comments and references added, changes in wording, version published in Phys. Rev.

Determinations of |V_ub| and |V_cb| from measurements of B -> X_u,c\ell\nu differential decay rates

Methods are described in the framework of light-cone expansion which allow one to determine the Cabibbo-Kobayashi-Maskawa matrix elements |V_ub| and |V_cb| from measurements of the differential decay rates as a function of the scaling variables in the inclusive semileptonic decays of B mesons. By these model-independent methods the dominant hadronic uncertainties can be avoided and the B -> X_u\ell\nu decay can be very efficiently differentiated from the B -> X_c\ell\nu decay, which may lead to precise determinations of |V_ub| and |V_cb|.Comment: 11 pages, 2 figures, version as published in Mod. Phys. Lett. A, more discussion, references added, title chang

Long distance effects on the B\to X_s\gamma photon energy spectrum

We compute long distance effects on the photon energy spectrum in inclusive radiative decays of $B$ mesons using light-cone expansion and heavy quark effective theory. We show that for sufficiently high photon energy the leading nonperturbative QCD contribution is attributed to the distribution function. The distribution function is found to be universal in the sense that the same distribution function also encodes the leading nonperturbative contribution to inclusive semileptonic decays of $B$ mesons at large momentum transfer. Some basic properties of the distribution function are deduced in QCD. Ways of extracting the distribution function directly from experiment and their implications are discussed. The theoretically clean methods for the determination of $|V_{ts}|$ are described.Comment: 18 pages, Late