[en] We have calculated the decay rates of several non-leptonic decays of charmed-mesons, using the spectator model. What distinguishes our approach is that we are able to obtain the decay matrix element of the meson from the constituent quarks' decay matrix element and the bound-state quark-antiquark wavefunction of the meson. The quarks' decay matrix element is calculated from the Standard Model. It is multiplied by the momentum-space wavefunction of the mesons, and integrated over the degrees of freedom of the constituent quarks, to give the decay matrix element of the meson. From this we can obtain the weak decay-rates of the charmed mesons. The wavefunctions we have used are based on a simple harmonic oscillator potential between the quark and the anti-quark. The resulting decay rates and lifetimes of the charmed mesons agree favourably with experimental measurements

[en] It has been argued that the mesonic Λ decay in nuclei is very much enhanced because the Pauli blocking, responsible for the small values of this width, is only partly effective if one has occupation numbers around 0.85, rather than 1, for the states below the Fermi surface. We revise this idea within the Lehmann representation for the nucleon propagator and find the idea to be wrong

[en] If the field of hypernuclear decay has been enjoying a renewal of interest for a few years, after the long silence of the seventies, it is most probably because i) technical developments have made it possible to use the high energy released (≅ 170 MeV) in the identification procedure, ii) owing to the large momentum transfer involved, it is expected that short-range properties of nuclei play an important role⁵⁾ and the quark structure of nuclei could be deeply implied. A short review of the experimental and theoretical work performed during this period is presented here

[en] The recent measurements on a number of b → sμ ⁺ μ ⁻ processes have manifested anomalous results which could be early evidence for the presence of new physics beyond the standard model in b → s transitions. Supposing this to be the case, we entertain the possibility that a heavy Z′ boson is responsible for these anomalies and that it also affects the rare nonleptonic decays of the ${\stackrel{¯<!--\; ??\; -->}{B}}_s$ meson which receive substantial contributions from the so-called penguin diagrams. The majority of these ${\stackrel{¯<!--\; ??\; -->}{B}}_s$ decay modes are not yet discovered, and within the standard model their rates have been estimated to be relatively suppressed. Taking into account various constraints, we find that the Z′ effects can enlarge the rates of a few of the modes, especially ${\stackrel{¯<!--\; ??\; -->}{B}}_s\to <!--\; ???\; -->\mathrm{\eta <!--\; ??\; -->}{\mathrm{\pi <!--\; ??\; -->}}^0,\mathrm{\varphi <!--\; ??\; -->}{\mathrm{\pi <!--\; ??\; -->}}^0,\mathrm{\eta <!--\; ??\; -->}\mathrm{\omega <!--\; ??\; -->},\mathrm{\varphi <!--\; ??\; -->}\mathrm{\omega <!--\; ??\; -->}$, considerably above their standard-model expectations. Consequently this Z′ scenario may be experimentally testable in the near future. (paper)

[en] Constraints on quark diagrams for exclusive decays from group theory are investigated. In contrast to previous statements, we find a one-to-one correspondence between reduced matrix elements of flavor symmetry (SU₃) and the ''naive'' quark diagrams of the spectator and annihilation type. In Cabibbo suppressed decays however, group theory relates penguin and annihilation (W-exchange) diagrams, consequently ruling out models with spectator dominance and large penguins. These results are expected to be more general, having as yet been illustrated for two-body decays of charmed mesons

[en] Results of a recent calculation of the effective ΔS = 1 Hamiltonian at the next-to-leading order will be presented. These, together with an improved treatment of hadronic matrix elements, are used to evaluate the measure for direct CP-violation, ε'/ε, at the next-to-leading order. The dependencies of ε'/ε on Λ_MSbar, m_t, and some B-parameters, parameterizing hadronic matrix elements, are briefly discussed. 1 fig., 2 tabs., 12 refs

[en] Recent results from CLEO measurements at the UPSILONsub(AS) are reported. Results are consistent with the standard model with six quarks and inconsistent with a broad class of exotic models. A charged Higgs scalar particle with M < Msub(B) is ruled out. Branching ratios for B → Xeν = 13.6 +- 2.1% and B → Xμν = 10.0 +- 1.3 +- 2.1% and an upper limit for the flavor charging neutral current decay of B → Xl⁺l^- < .74% (90% CL) are reported. Results on charged multiplicities from semi-leptonic and nonleptonics B decays together with the inclusive rate for K mesons are presented

[en] The standard model of particle physics is the most successful theory in describing the fundamental microscopic structure of matter in the universe. It consists of the theory of quantum chromodynamics for the strong interaction, and the electro-weak theory for the weak and electromagnetic (EW) interactions. In the quantum chromodynamics (QCD) theory, the nature of the quark confinement and low-energy non-perturbative property is still not clear;in the electro-weak theory, more stringent parameter constraints and experimental tests are required. The Beijing Electron-Position Collider (BEPCII) and Beijing Spectrometer (BESIII) are amongst the earliest largescale scientific facilities in China, and the only ones in the world still conducting high-luminosity experiments in the tau-charm energy region. They focus on research in hadron physics, non-perturbative effects in QCD, precision tests of the EW theory, and the search for new physics beyond the standard model. This article will review the highlights of the BESIII experiments during the past decades, such as the precise measurement of the tau lepton mass, the R value measurement, studies on the exotic hadrons, and measurements of the charmed hadron weak decays. (authors)

No abstract available

[en] Mesons with beauty and charm are an interesting theoretical laboratory that should soon become accessible to experiment. One can predict the properties of c bar b states with confidence. In particular, the mass of the ground-state B_c is expected to lie close to 6356 MeV/c². More than a dozen narrow states lie below flavor threshold. They cascade to the ground state by making electromagnetic or hadronic transitions within the c bar b spectrum. The excited states are extraordinarily narrow. They may be observable in γ or ππ coincidences with B_c. Weak decays of B_c are affected by the strong binding of the bar b and c constituents. The authors estimates of the semi-inclusive decay rates lead to a lifetime τ(B_c) ∼ 1.35 ± 0.15 ps that is appreciably longer than the guess τ(B_c) ∼ (1/τ_b + 1/τ_c)^-1 ∼ 0.71 to 0.88 ps, which neglects binding. The semi-inclusive analysis understates the important of B_s + light hadron modes. The author's best lifetime estimates is 1.1 to 1.2 ps. Finally, while B_c is an exotic - indeed, undiscovered - state today, it may have important practical applications in the future. The decay B_c → B_s ell may provide a clean and efficient flavor tag for B_s