Charming penguin contributions to B => K \pi

We present calculations of the charming-penguin long-distance contributions to B => K \pi decays due to intermediate charmed meson states. Our calculation is based on the Chiral Effective Lagrangean for light and heavy mesons, corrected for the hard pion and kaon momenta. We find that the charming-penguin contributions increase significantly the B => K \pi decay rates in comparison with the short-distance contributions, giving results in better agreement with experimental data.Comment: 13 pages LaTeX (uses RevTeX and epsfig), 3 figures. Corrected typos. To appear in Physical Review

Testing QCD factorisation and charming penguins in charmless B→PV{\boldsymbol{B\to PV}}

We try a global fit of the experimental branching ratios and CP-asymmetries of the charmless $B\to PV$ decays according to QCD factorisation. We find it impossible to reach a satisfactory agreement, the confidence level (CL) of the best fit is smaller than .1 %. The main reason for this failure is the difficulty to accomodate several large experimental branching ratios of the strange channels. Furthermore, experiment was not able to exclude a large direct CP asymmetry in $\bar {B^0}\to\rho^+ \pi^-$, which is predicted very small by QCD factorisation. Trying a fit with QCD factorisation complemented by a charming-penguin inspired model we reach a best fit which is not excluded by experiment (CL of about 8 %) but is not fully convincing. These negative results must be tempered by the remark that some of the experimental data used are recent and might still evolve significantly.Comment: 21 pages, 4 figures; several typos corrected, added one footnote and two references, comments added about PQCD. To appear in Phys.Rev.

Branching ratios and CP-violating asymmetries of Bs→h1h2B_s \to h_1 h_2 decays in the general two-Higgs doublet models

Based on the low-energy effective Hamiltonian with the generalized factorization, we calculate the new physics contributions to branching ratios and CP-violating asymmetries of the charmless hadronic decays $B_s \to h_1 h_2$ in the standard model and the general two-Higgs doublet models (models I, II, and III). Within the considered paramter space, we find the following. (a) In models I and II, the new physics corrections are always small in size and will be masked by other larger known theoretical uncertainties. (b) In model III, the new physics corrections to the branching ratios of those QCD penguin-dominated decays \ov B_s \to K^0\etapp, K^+ K^{-*}, etc., are large in size and insensitive to the variations of \mhp and \nceff. For tree- or electroweak penguin-dominated decay modes, however, the new physics corrections are very small in size. (c) For \ov B_s \to K^+ K^{-*} and other seven decay modes, the branching ratios are at the level of $(1-3)\times 10^{-5}$ and will be measurable at the future hadron colliders with large $b$ production. (d) Among the studied thirty nine $B_s$ meson decay modes, seven of them can have a CP-violating asymmetry ${\cal A}_{CP}$ larger than 20% in magnitude. The new physics corrections are small or moderate in magnitude. (e) Because of its large and \nceff stable branching ratio and CP violating asymmetry, the decay \ov B_s \to K^+ K^{-*} seems to be the "best" channel to find CP violation of $B_s$ system through studies of two-body charmless decays of $B_s$ meson.Comment: 39 pages, Revtex, 9 eps figures, final version accepted for publication in Phys.Rev.

Charmless hadronic decays B→PP,PV,VVB \to PP, PV, VV and new physics effects in the general two-Higgs doublet models

Based on the low-energy effective Hamiltonian with the generalized factorization, we calculate the new physics contributions to the branching ratios of the two-body charmless hadronic decays of $B_u$ and $B_d$ mesons induced by the new gluonic and electroweak charged-Higgs penguin diagrams in the general two-Higgs doublet models (models I, II and III). Within the considered parameter space, we find that: (a) the new physics effects from new gluonic penguin diagrams strongly dominate over those from the new $\gamma$- and $Z^0$- penguin diagrams; (b) in models I and II, new physics contributions to most studied B meson decay channels are rather small in size: from -15% to 20%; (c) in model III, however, the new physics enhancements to the penguin-dominated decay modes can be significant, $\sim (30 -200)$, and therefore are measurable in forthcoming high precision B experiments; (d) the new physics enhancements to ratios {\cal B}(B \to K \etap) are significant in model III, $\sim (35 -70)$, and hence provide a simple and plausible new physics interpretation for the observed unexpectedly large B \to K \etap decay rates; (e) the theoretical predictions for ${\cal B}(B \to K^+ \pi)$ and ${\cal B}(B \to K^0 \pi^+)$ in model III are still consistent with the data within $2\sigma$ errors; (f) the significant new physics enhancements to the branching ratios of $B \to K^0 \pi^0, K^* \eta, K^{*+} \pi^-, K^+ \phi, K^{*0} \omega, K^{*+} \phi$ and $K^{*0} \phi$ decays are helpful to improve the agreement between the data and the theoretical predictions; (g) the theoretical predictions of ${\cal B}(B \to PP, PV, VV)$ in the 2HDM's are generally consistent with experimental measurements and upper limits ($90$)Comment: 55 pages, Latex file, 17 PS and EPS figures. With minor corrections, final version to be published in Phys.Rev. D. Repot-no: PKU-TH-2000-4

Search for rare and forbidden decays of charm and charmed-strange mesons to final states h^+- e^-+ e^+

We have searched for flavor-changing neutral current decays and lepton-number-violating decays of D^+ and D^+_s mesons to final states of the form h^+- e^-+ e^+, where h is either \pi or K. We use the complete samples of CLEO-c open-charm data, corresponding to integrated luminosities of 818 pb^-1 at the center-of-mass energy E_CM = 3.774 GeV containing 2.4 x 10^6 D^+D^- pairs and 602 pb^-1 at E_CM = 4.170 GeV containing 0.6 x 10^6 D^*+-_s D^-+_s pairs. No signal is observed in any channel, and we obtain 90% confidence level upper limits on branching fractions B(D^+ --> \pi^+ e^+ e^-) < 5.9 x 10^-6, B(D^+ --> \pi^- e^+ e^+) K^+ e^+ e^-) < 3.0 x 10^-6, B(D^+ --> K^- e^+ e^+) \pi^+ e^+ e^-) < 2.2 x 10^-5, B(D^+_s --> \pi^- e^+ e^+) K^+ e^+ e^-) < 5.2 x 10^-5, and B(D^+_s --> K^- e^+ e^+) < 1.7 x 10^-5.Comment: 9 pages, available through http://www.lns.cornell.edu/public/CLNS

Measurement of the B-Meson Inclusive Semileptonic Branching Fraction and Electron-Energy Moments

We report a new measurement of the B-meson semileptonic decay momentum spectrum that has been made with a sample of 9.4/fb of electron-positron annihilation data collected with the CLEO II detector at the Y(4S) resonance. Electrons from primary semileptonic decays and secondary charm decays were separated by using charge and angular correlations in Y(4S) events with a high-momentum lepton and an additional electron. We determined the semileptonic branching fraction to be (10.91 +- 0.09 +- 0.24)% from the normalization of the electron-energy spectrum. We also measured the moments of the electron energy spectrum with minimum energies from 0.6 GeV to 1.5 GeV.Comment: 36 pages postscript, als available through http://w4.lns.cornell.edu/public/CLNS/, Submitted to PRD (back-to-back with preceding preprint hep-ex/0403052