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We study the $f^+$ form factor for the $bar B_sto K^+ell^-bar u_ell$ semileptonic decay in a nonrelativistic quark model. The valence quark contribution is supplemented with a $bar B^*$-pole term that dominates the high $q^2$ region. To extend the quark model predictions from its region of applicability near $q^2_{rm max}=(M_{B_s}-M_K)^2$, we use a multiply-subtracted Omn`es dispersion relation. We fit the subtraction constants to a combined input from previous light cone sum rule results in the low $q^2$ region and the quark model results (valence plus $bar B^*$-pole) in the high $q^2$ region. From this analysis, we obtain $Gamma(bar B_sto K^+ell^-bar u_ell)=(5.47^{+0.54}_{-0.46})|V_{ub}|^2times 10^{-9},{rm MeV}$, which is about 10% and 20% higher than predictions based on Lattice QCD and QCD light cone sum rules respectively.
We study the $f^+$ form factor for the semileptonic $bar B_sto K^+ell^-bar u_ell$ decay in a constituent quark model. The valence quark estimate is supplemented with the contribution from the $bar B^*$ pole that dominates the high $q^2$ region. We us
Using data collected by the fixed target Fermilab experiment FOCUS, we present several first measurements for the semileptonic decay $D^0 to bar{K}^0pi^-mu^+ u$. Using a model that includes a $bar{K}^0 pi^-$ S-wave component, we measure the form fact
We use lattice QCD to calculate the form factors $f_+(q^2)$ and $f_0(q^2)$ for the semileptonic decay $B_sto Kell u$. Our calculation uses six MILC asqtad 2+1 flavor gauge-field ensembles with three lattice spacings. At the smallest and largest latti
A critical review is presented of the attempts to estimate the Strong Interactions contributions to the parameter $S$ ($L_{10}$ in the QCD Chiral Version). In particular it is discussed why the estimations done for Technicolor are unreliable. $S$ is
We present updates for our nonperturbative lattice QCD calculations to determine semileptonic form factors for exclusive $Bto piell u$, $Bto D ell u$, $B_sto Kell u$, and $B_sto D_sell u$ decays. Our calculation is based on RBC-UKQCDs set of $2+1$-d