Cheng-Wei Chiang

Charmless B ---> P P decays using flavor SU(3) symmetry

The decays of B mesons to a charmless vector (V ) and pseudoscalar (P) meson are analyzed within a framework of flavor SU(3) in which symmetry breaking is taken into account through ratios of decay constants in tree (T) amplitudes. The magnitudes and relative phases of tree and penguin amplitudes are extracted from data; the symmetry assumption is tested; and predictions are made for rates and CP asymmetries in as-yet-unseen decay modes. A key assumption for which we perform some tests and suggest others is a relation between penguin amplitudes in which the spectator quark is incorporated into either a pseudoscalar meson or a vector meson. Values of slightly restricting the range currently allowed by fits to other data are favored, but outside this range there remain acceptable solutions which cannot be excluded solely on the basis of present B → V P experiments.

Z′ mediated flavor changing neutral currents in B meson decays

Abstract We study the effects of an extra U(1)′ gauge boson with flavor changing couplings with fermion mass eigenstates on certain B meson decays that are sensitive to such new physics contributions. In particular, we examine to what extent the current data on Bd→φK and Bd→η′K decays may be explained in such models, concentrating on the example in which the flavor changing couplings are left-chiral. We find that within reasonable ranges of parameters, the Z′ contribution can readily account for the anomaly in SφKS but is not sufficient to explain large branching ratio of Bd→η′K with the same parameter value. SφKS and Sη′KS are seen to be the dominant observables that constrain the extra weak phase in the model.

Solution to the B → π K puzzle in a flavor-changing Z' model

Abstract Recent experiments suggest that certain B → π K branching ratios are inconsistent with the standard model expectations. We show that a flavor-changing Z ′ provides a solution to the problem. Electroweak penguin amplitudes are enhanced by the Z ′ boson for select parameters. We discuss implications for the Z ′ mass and its couplings to the standard model fermions. We also show that the solution is consistent with constraints from the CP asymmetries of the B → ϕ K S decay.

Direct CP violation in two-body hadronic charmed meson decays

Motivated by the recent observation of

Revisiting scalar and pseudoscalar couplings with nucleons

CP

Implications of Higgs boson search data on the two-Higgs doublet models with a softly broken Z2 symmetry

violation in the charm sector by LHCb, we study direct

Search for doubly charged Higgs bosons using the same-sign diboson mode at the LHC

CP

Proton Size Anomaly

asymmetries in the standard model (SM) for the singly Cabibbo-suppressed two-body hadronic decays of charmed mesons using the topological-diagram approach. In this approach, the magnitude and the phase of topological weak annihilation amplitudes, which arise mainly from final-state rescattering, can be extracted from the data. Consequently, direct

Flavor SU(3) analysis of charmless B meson decays to two pseudoscalar mesons

CP

SU(3) symmetry breaking and CP violation in D -> PP decays

asymmetry