In this work, we perform a combined analysis of the R(D), R(D * ), and R(J/ψ) anomalies in a modelindependent manner based on the general framework of the four-fermion effective field theory, paying special attention to the use of the hadronic form factors. For the B → D(D * ) transition form factors, we use the HQET parametrization that includes the higher order corrections of O(α s , Λ QCD /m b,c ) and was determined recently from a fit to lattice QCD and light-cone sum rule results in complementary kinematical regions of the momentum transfer. For the B c → J/ψ(η c ) transitions, we use the form factors calculated in the covariant light-front quark model, which are found to be well consistent with the preliminary lattice results. With this particular treatment of hadronic matrix elements, in our analysis the two classes of vector operators are shown to be the most favored single new physics (NP) operators by the current experimental constraints within 2σ and the LEP1 data on Br(B c → τν) as well as the minimum χ 2 fit, while the tensor operator is also allowed but severely constrained, and the scalar ones are excluded. Using the favored ranges and fitted values of the Wilson coefficients of the single NP operators, we also give a prognosis for the physical observables such as the ratios of decay rates (R(D(D * )), R(J/ψ(η c ))) and other polarized observables as well as the q 2 distributions.

We study long-distance effects in rare exclusive semileptonic decays B → K 1 ℓ + ℓ − , K 1 is the axial vector meson.The form factors, describing the meson transition amplitudes of the effective Hamiltonian, are calculated using Ward identites which are then used to calculate branching ratio and forward-backward asymmetry in these decay modes. The zero of forward-backward asymmetry is of special interest and provide us the precission test of Standard model.

We compute couplings between the ρ-meson and D-and D * -mesons -D ( * ) ρD ( * ) -that are relevant to phenomenological meson-exchange models used to analyse nucleon-D-meson scattering and explore the possibility of exotic charmed nuclei. Our framework is built from elements constrained by Dyson-Schwinger equation studies in QCD, and therefore expresses a simultaneous description of light-and heavy-quarks and the states they constitute. We find that all interactions, including the three independent D * ρ D * couplings, differ markedly amongst themselves in strength and also in range, as measured by their evolution with ρ-meson virtuality. As a consequence, it appears that one should be cautious in using a single coupling strength or parametrization for the study of interactions between D ( * ) -mesons and matter.