U-spin symmetry in doubly Cabibbo-suppressed charmed meson decays

We prove a U-spin amplitude triangle relation among doubly Cabibbo-suppressed (DCS) charmed meson decays, D⁰→K⁺π⁻,D⁰→K⁰π⁰ and D⁺_s→K⁰K⁺, congruent to an isospin relation among corresponding Cabibbo-favored (CF) decays. U-spin breaking in relative phases between CF and DCS amplitudes affects time-dependent studies of D⁰– mixing. Comparison of final state phase patterns in DCS and CF amplitude triangles, which can shed some light on these phases, is carried out in a phenomenological framework incorporating resonance contributions.     

Ways to measure the hairpin diagram in charmed meson decays

The possible presence of hairpin diagrams is analyzed in th model-independent quark-diagram scheme for two-body decays of charmed mesons. Current experimental data do not require the presence of hairpin diagrams inDVP (V: vector meson,P: pseudoscalar meson), in accordance with the OZI rule. However, there is a possible indication that they are important in the decay ofDPP. The measurement ofD _s ^{+ +} is crucial to test the mechanism of hairpin diagrams.     

Final states in non-leptonic bottom meson decays

We use Isospin-Statistical Models to study many body final states in the non-leptonic decays of bottom mesons in the framework of the Kobayashi-Maskawa weak current. Estimates of charge multiplicities, branching ratios and inclusive hadron momentum distributions are presented.     

CP violation for neutral charmed meson decays into CP eigenstates

The CP asymmetries for the decays of the neutral charmed meson into CP eigenstates are carefully studied. Formulas and numerical results are presented. The impact on experiments is briefly discussed.     

Lepton mass correction in partial wave analyses of charmed meson semi-leptonic decays

We derive a parameterization formula for the partial wave analyses of charmed meson semi-leptonic decays while considering the effects of lepton mass. Because the proposed super-tau-charm factory will reach a significantly enhanced luminosity and BESIII is collecting new ψ(3770) → ■ data, our results will help improve the measurement precision of future partial wave analyses of charmed meson semi-muonic decays.     

Soft-gluon effects in nonleptonic decays of charmed mesons

Soft-gluon effects in nonleptonic decays of D and F mesons are studied nonperturbatively by use of a QCD multipole expansion. For reasonable values of D-meson bound-state parameters, the soft-gluon effects lead to a significant difference in the lifetimes of the D⁰ and D⁺ mesons.     

Soft-gluon effects in semileptonic decays of charmed F mesons

The QCD multipole expansion is applied to the study of nonperturbative soft-gluon effects in semileptonic decays of charmed F mesons. For reasonable values of F-meson bound-state parameters, the soft-gluon effects activate quark-annihilation processes, leading to a significant enhancement of semileptonic decay rates.     

New physics effects from B meson decays

In this talk, we point out some of the present and future possible signatures of physics beyond the Standard Model from B-meson decays, taking R-parity conserving and violating supersymmetry as illustrative examples. An expanded version is available on hep-ph archive.     

Final state gluon polarization in large transverse momentum quarkonium production

We calculate the polarization of the final state gluon in the processes thought to dominate large transverse momentum quarkonium production atep colliders ( \((\gamma g \to g^3 S_1 (Q\bar Q))\) ) and at hadron colliders \((gg \to g^3 S_1 (Q\bar Q), gg \to g^3 P_J (Q\bar Q) (J = 0,1,2))\) . We find that the polarization is never more than 10%.     

Semi-leptonic decays of charmed baryons

We present estimates of semi-leptonic decays of the charmed $\text{1+}\text{2}$ baryons, members of the SU(3) 3¹ and 6 multiplets, into ordinary $\text{1+}\text{2}\text{and}\text{3+}\text{2}$ baryons. We give general expressions for decay rates and the mass M(B⁺?) spectra. We relate the relevant form factors for the $\text{1+}\text{2}\text{→}\text{1+}\text{2}$ transitions to the electromagnetic ones by means of CVC and SU(4). The form factors for $\text{1+}\text{2}\text{→}\text{3+}\text{2}$ transitions are related through SU(4) to those measured in Δ production. We discuss the dependence of the results on the masses of charmed baryons. The $\text{1+}\text{2}\text{→}\text{1+}\text{2}$ and $\text{1+}\text{2}\text{→}\text{3+}\text{2}$ transitions turn out to be dominant for the decays of the multiplets 3¹ and 6, respectively. The partial lifetimes are O(10^?10 ? 10^?14) sec as the masses of the decaying baryons are varied from 2 to 2.9 GeV. Possible ways of getting an idea about the masses of the charmed baryons are given.     

Manifestation of intermediate meson loop effects in charmonium decays

We report the progress on understanding some of those existing puzzles in charmonium decays.We show that the intermediate meson loops (IML) as a long-distance transition mechanism will provide novel insights into these issues.In particular,we show that the IML mechanism would be essentially important for understanding the ψ(3770) non-DD decays.We also comment that such a mechanism is correlated with the Okubo-Zweig-Iizuka (OZI) rule evasions in charmonium hadronic decays.     

Manifestation of intermediate meson loop effects in charmonium decays

We report the progress on understanding some of those existing puzzles in charmonium decays.We show that the intermediate meson loops （IML） as a long-distance transition mechanism will provide novel insights into these issues.In particular,we show that the IML mechanism would be essentially important for understanding the ψ（3770） non-DD decays.We also comment that such a mechanism is correlated with the Okubo-Zweig-Iizuka （OZI） rule evasions in charmonium hadronic decays.     

Weak decays of charmed baryons

We use the quark model framework to calculate the weak decays of the lowest lying charmed baryons into ground state baryons and mesons. We present detailed results on the predicted flavour and multipole composition of the final state configurations which can be tested in the near future. For the decays 1/2⁺→1/2⁺+0^? we also give symmetry and current algebra estimates which we compare with the quark model results. Semileptonic branching ratios in charmed baryon decays are calculated to be of the order of ～5%. The total lifetime of charmed baryons is predicted to be ～7 10^?14 s which is 5–10 times smaller than the free quark model estimate.