Narrow Results

The ratios of B_d and B_s meson decay constant have been estimated using the variational method in conjunction with the relativistic Hamiltonian of the heavy meson in the framework of the statistical model. The ratio of CKM matrix elements has been extracted from mixing using the estimated decay constants and ratio of B_d and B_s mass differences. The results are found to be in good agreement with the existing theoretical and experimental predictions.

The decay constant of is the key quantity to determine the production rate of in τ decays. By assuming is the lowest scalar bound state of , the decay constant can be calculated reliably in QCD sum rule. Then the decay branching ratio of is predicted to be about (7.9±3.1)×10^-5. If this branching ratio can be measured by experiment, it should be helpful to make clear the structure of .

In this work, we investigate the masses of a few heavy–light mesons with variational method, taking into account the two-loop effects in the static Cornell potential. Specifically, we consider two wave functions, Gaussian and Coulomb. Our analysis suggests that phenomenologically such approach is more successful in the heavy flavored meson sector than the stationary state perturbation theory and other approximation methods.

We present the first results from a recent pilot run of the CLEO-c experiment. This new program investigates the physics of charm mesons and charmonium resonances. We begin with results on two-body decays of the ψ(2S); first observations of some highly-suppressed "PV" modes are presented. Next, data taken at the ψ(3770) are used for a variety of studies of D meson decays in a very clean environment. We report the cross-section at the ψ(3770), extract f_D from the first significant sample of D⁺→μ⁺ν_μ decays, and investigate both inclusive and exclusive semileptonic D decays.

We report measurements of the branching fractions for the leptonic decays D⁺ → μ⁺ν_μ and from the CLEO-c experiment. From these measurements we extract the decay constants and f_Ds = 280.1 ± 11.6 ± 6.0 MeV.

The decay constants of S wave and P wave heavy mesons are computed by means of the relativistic (instantaneous) Salpeter equation.

The masses and decay constants of the light tensor mesons were calculated with quantum numbers $J^P=2^{+}$ in the framework of the QCD sum rules in the standard model. The non perturbative contributions up to dimension-5 are considered as important terms of the operator product expansion.

In this paper, we incorporate three-loop contributions in the strong coupling constant and study their effects in the wave functions, masses and decay constants of heavy–light pseudo-scalar mesons (PSM) $D$, $D_s$, $B$ and $B_s$ in V-scheme. In this work, we use the standard linear plus inverse distance QCD potential in association with Dalgarno’s method of perturbation theory for linear parent option. Detailed comparison is done with the results from Lattice QCD, QCD sum rules, light-front quark model (LFQM), relativistic harmonic confinement model (RHCM) and recent PDG data.

The quark–antiquark potential is one of the basic ingredients of QCD-inspired potential models. This work will report the results of the masses and decay constants of heavy-flavor pseudo-scalar mesons within a QCD-based potential model having both inverse distance Coulomb and the linear confinement pieces. To that end, we use the inverse piece incorporating two-loop effects as suggested in V-scheme. Quantum mechanical perturbative methods: Dalgarno’s method of perturbation theory and variationally improved perturbation theory are used for the investigation. We use the Coulombic piece as the parent which is allowed by both Dalgarno’s perturbation theory and variationally improved perturbation theory. The results are compared with the latest updated theoretical predictions and PDG data. The sensitivity of the input parameters of the model has been discussed.

The Wigner–Weyl transform and phase space formulation of a density matrix approach are applied to a non-Hermitian model which is quadratic in positions and momenta. We show that in the presence of a quantum environment or reservoir, mean lifetime and decay constants of quantum systems do not necessarily take arbitrary values, but could become functions of energy eigenvalues and have a discrete spectrum. It is demonstrated also that a constraint upon mean lifetime and energy appears, which is used to derive the resonance conditions at which long-lived states occur. The latter indicate that quantum dissipative effects do not always lead to decay but, under certain conditions, can support stability of a system.

We intend to study the alpha-decay half-lives of some nuclei from ground state to ground state. We consider a potential model with Yukawa proximity potential. We see that the results are in good agreement with the experimental data.

I present the measurements and limits of the branching fractions of leptonic decays of the D_s meson, and the subsequent estimation of the decay constant f_Ds, using the complete BaBar dataset (530 fb^-1). we measure , , , , and f_Ds = (258.6±6.4±7.5)MeV, where the first uncertainties are statistical and the second uncertainties are systematic.

I report preliminary CLEO-c results on purely leptonic decays of the D_s using 195 pb^-1 of data at 4.170 GeV. We measure f_Ds = 280.1 ± 11.6 ± 6.0 MeV, and f_Ds+/f_D⁺ = 1.26 ± 0.11 ± 0.03.

It is shown that the conventional mesons and the lowest glueball state can be reasonably described within a simple relativistic quantum-field model of interacting quarks and gluons under the analytic confinement by using a path-integral approach. The ladder Bethe-Salpeter equation is solved for the meson and glueball (gg) spectra. A minimal set of parameters (the quark masses m_f, the coupling constant α_s and the confinement scale Λ) is used to fit the latest experimental data. In spite of the simplicity, the model provides a reasonable framework to estimate the decay constants f_π and f_K as well as the non-exotic meson and glueball masses in a wide range of energy up to 10 GeV.