[en] Within the hidden local symmetry framework, the Dalitz decay η"′→Ve"+e"− is studied with the vector meson dominance model. It is found that the partial width Γ(η"′→ωe"+e"−) ≈ 40~eV and branching ratio B(η"′→ωe"+e"−) ≈ 2×10"−"4, and Γ(η"′→ρe"+e"−) ≈ 10Γ(η"′→ωe"+e"−) and B(η"′→ρe"+e"−) ≈ 10B(η"′→ωe"+e"−). The maximum position of the dilepton distribution is m_e_"+_e_"−≈1.33~MeV. These decays are measurable with the advent of high statistic η"′ experiments

[en] The charm quark offers interesting opportunities to cross-check the mechanism of CP violation precisely tested in the strange and beauty sectors. In this paper, we exploit the angular and quantum correlations in the D D-bar pairs produced through the decay of the ψ(3770) resonance in a charm factory to investigate CP-violation in two different ways. We build CP-violating observables in ψ(3770) → D D-bar → (V₁V₂)(V₃ V₄) to isolate specific New Physics effects in the charm sector. We also consider the case of ψ(3770) → D D-bar → (V₁V₂)(K π) decays, which provide a new way to measure the strong phase difference delta between Cabibbo-favoured and doubly-Cabibbo suppressed D decays required in the determination of the CKM angle γ. Neglecting the systematics, we give a first rough estimate of the sensitivities of these measurements at BES-III with an integrated luminosity of 20 fb^-1 at ψ(3770) peak and at a future Super τ-charm factory with a luminosity of 10³⁵ cm^-2 s^-1. (authors)

[en] Motivated by recent $R_D$, $R_{D^{⁎}}$ and $R_{J/\psi }$ anomalies in $B\to D{\ell }^{-}{\overline{\nu }}_{\ell }$, $B\to D^{⁎}{\ell }^{-}{\overline{\nu }}_{\ell }$ and $B_c\to J/\psi {\ell }^{-}{\overline{\nu }}_{\ell }$ decays, respectively, we study possible R-parity violating supersymmetric effects in $B_c\to J/\psi {\ell }^{-}{\overline{\nu }}_{\ell },{\eta }_c{\ell }^{-}{\overline{\nu }}_{\ell }$ and ${\mathrm{\Lambda }}_b\to {\mathrm{\Lambda }}_c{\ell }^{-}{\overline{\nu }}_{\ell }$ decays, which are also induced by $b\to c{\ell }^{-}{\overline{\nu }}_{\ell }$ at quark level. We find that (I) the constrained slepton exchange couplings ${\lambda }_{i33}{\tilde{\lambda }}_{i23}^{\prime ⁎}$ involving in $b\to c{\tau }^{-}{\overline{\nu }}_{\tau }$ transition from relevant latest experimental data still have quite large effects on all (differential) branching ratios and the normalized forward–backward asymmetries of the exclusive semileptonic $b\to c{\tau }^{-}{\overline{\nu }}_{\tau }$ decays as well as the ratios of the (differential) branching ratios; (II) after satisfying the data of $R_D$ and $R_{D^{⁎}}$, the upper limit of $R_{J/\psi }$, $R_{{\eta }_c}$ and $R_{{\mathrm{\Lambda }}_c}$ could be increased by 10%, 112% and 24%, respectively, from their upper limits of the Standard Model predictions by the ${\lambda }_{i33}{{\tilde{\lambda }}^{\prime ⁎}}_{i23}$ couplings. The results in this work could be used to probe R-parity violating effects and will correlate with searches for direct supersymmetric signals at the running LHCb and the forthcoming Belle-II.