Narrow Results

In this contribution I review some recent developments in charmonium spectroscopy, and discuss related theoretical predictions. The spectrum of states, strong decays of states above open charm threshold, electromagnetic transitions, and issues related to the recent discoveries of the "XYZ" states are discussed. Contributions that BES can make to our understanding of charmonium and related states are stressed in particular.

We determine the value of the ω-ρ-π mesons coupling (g_ωρπ), in the context of the vector meson dominance model, from radiative decays, the ω→3π decay width and the e⁺e^-→3π cross-section. For the last two observables we consider the effect of either a heavier resonance (ρ′(1450)) or a contact term. A weighted average of the results from the set of observables yields g_ωρπ = 14.7±0.1 GeV^-1 in absence of those contributions, and g_ωρπ = 11.9 ± 0.2 GeV^-1 or g_ωρπ = 11.7 ± 0.1 GeV^-1 when including the ρ′ or contact term, respectively. The inclusion of these additional terms makes the estimates from the different observables to lay in a more reduced range. Improved measurements of these observables and the ρ′(1450) meson parameters are needed to give a definite answer on the pertinence of the inclusion of this last one in the considered processes.

The heavy diquark symmetry (HDS) of doubly heavy baryons (DHBs) provides new insights into the spectroscopy of these hadrons. We derive the consequences of this symmetry for the mass spectra and the decay widths of DHBs. We compare these symmetry constraints to results from a nonrelativistic quark model for the mass spectra and results from the ³P₀ model for strong decays. The quark model we implement was not constructed with these symmetries and contains interactions which explicitly break HDS. Nevertheless these symmetries emerge. We argue that the ³P₀ model and any other model for strong transitions which employs a spectator assumption explicitly respects HDS. We also explore the possibility of treating the strange quark as a heavy quark and apply these ideas to Ξ, Ξ_c and Ξ_b baryons.

The first radial excitations of axial-vector mesons are considered in the framework of the extended U(3) × U(3) Nambu–Jona-Lasinio model. We calculate the mass spectrum of a₁, f₁ and also strange axial-vector mesons. For description of radially excited states, we used the form factors of polynomial type of the second order in transverse quark momentum. For the ground- and excited-state mesons consisting of light quarks we have calculated the widths of a number of strong and radiative decays. We got satisfactory agreement with experimental data for the ground states. A set of predictions for the excited states of mesons is given.

In this paper, we assign the newly reported state $X(3842)$ to be a $D$-wave $\bar{c}c$ meson, and study its mass and decay constant with QCD sum rules by considering the contributions of vacuum condensates up to dimension-6 in the operator product expansion. The predicted mass $M_{X(3842)}=\left(\right.3.844_{-0.0823}^{+0.0675}\pm 0.020\left)\right.$ GeV is in agreement with the experimental data $M_{X(3842)}=(3842.71\pm 0.16\pm 0.12)$ MeV from the LHCb collaboration. This result supports assigning $X(3842)$ as the $1^3{D}_3$ charmonium meson. In this case, its predicted strong decay width with the ${}^3{P}_0$ decay model is compatible with the experimental data.

The Higgs mechanism for imparting masses to gauge bosons and matter particles is obviated by showing that Yang–Mills gauge bosons have intrinsic nonzero masses (rest-frame energies) from self-interactions. Electroweak (EW) mixing is ruled out because it produces a photon field that is massive, carries EW charge, and does not satisfy Maxwell's equations. Other fundamental difficulties of the Standard Model are identified. A new gauge theory of electromagnetic, weak and strong interactions is derived from the Dirac equation with no other postulates and no free parameters. The three forces are intrinsically unified, the photon field is Maxwellian, weak interactions derive from spin (not isospin), and the weak and strong bosons are naturally massive and chiral. Charge is naturally quantized to integral values. Three generations of lepton pairs and elementary-hadron pairs, all with integral charges, are predicted, contradicting the phenomenology of fractional quark charges, but in full accord with experimental data on weak and strong processes and composite hadrons. Neutrinos are massive. The Dirac masses, the fine structure constant, neutrino oscillations and Cabibbo mixing are shown to have a common origin in the gravitational field. The new theory leads to a new interpretation of "negative energies" with cosmological implications. Finally, it is shown that key expressions of the EW formalism agree with those of the new theory and with experiments only if the mixing angle θ is given by sin² θ = 0.25, which accounts for the EW model's successes.

In this work, we have employed Bethe–Salpeter equation (BSE) under Covariant Instantaneous Ansatz (CIA) to study strong decays of first radial excitations, ω(1420) and ρ(1450) of lightest vector mesons, ω(782) and ρ(770) respectively, through the processes: ω(1420)→ρ+π and ρ(1450)→ω+π. The main motivation for this work was our intention to resolve the problems involved in calculations of triangle quark-loop diagrams as pointed out earlier in Ref. 1 which appear in processes such as h→h'+h" and h→h'+γ (attempted recently) in BSE under CIA, which gives rise to complexities in amplitudes making calculations difficult. We explicitly show the mathematical procedure for handling the process, h→h'+h" involving three hadron–quark vertex functions, which is more involved than that for h→h'+γ and leads to decay widths which are in rough agreement with data.

The ³P₀ model is used to investigate light-strange mesons strong decays. Decay amplitudes and decay widths are evaluated by using relativistic and non-relativistic simple harmonic oscillator (SHO) wave-functions. Numerical results are given for allowed open-flavor decay modes for and mesons. The results for the relativistic model are in good agreement with the recent published data.