Vector Meson Dominance Hypothesis Research Articles

Analysis of the b1 meson decay in local tensor bilinear representation

We explore the validity of vector meson dominance in the radiative decay of the b1(1235) meson. In order to explain the violation of the vector meson dominance hypothesis in this decay process, we investigate a model where the b1 meson strongly couples with the local current in tensor bilinear representation. The tensor representation is investigated in the framework of the operator product expansion and we found a low energy decay process that does not follow the usual vector meson dominance hypothesis. The ω-like intermediate meson state of quantum numbers IG(JPC) = 0−(1− −) is found to have a nontrivial role in the decay process of the b1 meson. The spectral structure of the ω-like state is found to be close to a π-ρ hybrid state, which provides a mechanism that evades the usual vector meson dominance hypothesis. Precise measurements of various decay channels of the b1 meson are, therefore, required to unravel the internal structure of axial vector mesons.

The radiative decay with vector meson dominance**J. M. Dias would like to thank the Brazilian funding agency FAPESP for the financial support (2016/22561-2), V. R. Debastiani wishes to acknowledge the support from the Programa Santiago Grisolia of Generalitat Valenciana (Exp. GRISOLIA/2015/005). This work is also partly supported by the Spanish Ministerio de Economia y Competitividad and European FEDER funds (FIS2014-57026-

Motivated by the experimental measurements of D0 radiative decay modes, we have proposed a model to study the decay, by establishing a link with (V=ρ0, ω) decays through the vector meson dominance hypothesis. In order to do this properly, we have used the Lagrangians from the local hidden gauge symmetry approach to account for Vγ conversion. As a result, we have found the branching ratio , which is in fair agreement with the experimental values reported by the Belle and BaBar collaborations.

Novel nonperturbative approach for radiativeB¯0(B¯s0)→J/ψγdecays

Radiative $\bar{B}^0(\bar{B}^0_s)\rightarrow J/\psi \gamma$ decays provide an interesting case to test our understanding of (non)perturbative QCD and eventually to probe physics beyond the standard model. Recently, the LHCb Collaboration has reported an upper bound, updating the results of the BABAR Collaboration. Previous theoretical predictions based on QCD factorization or perturbative QCD have shown large variations due to different treatment of nonfactorizable contributions and meson-photon transitions. In this paper, we report on a novel approach to estimate the decay rates, which is based on a recently proposed model for $B$ decays and the vector meson dominance hypothesis, widely tested in the relevant energy regions. The predicted branching ratios are $\mathrm{Br}[\bar{B}^0\rightarrow J/\psi\gamma]=\left(3.50\pm0.34^{+1.12}_{-0.63}\right)\times10^{-8}$ and $\mathrm{Br}[\bar{B}^0_s\rightarrow J/\psi\gamma]=\left(7.20\pm0.68^{+2.31}_{-1.30}\right)\times10^{-7}$. The first uncertainty is systematic and the second is statistical, originating from the experimental $\bar{B}^0_s\rightarrow J/\psi \phi$ branching ratio.

Radiative heavy meson transitions

We evaluate the radiative and hadronic decay rates of the D ∗ mesons using the Heavy Quark Effective Theory and the Vector Meson Dominance hypothesis. We also estimate the width of the B ∗ electromagnetic transitions and the radiative decays of positive parity J P = 0 +, 1 + charmed mesons.

Deviation from the exactSU 3 symmetry in hadronic decays of ψ and contributions of electromagnetic interactions

It is assumed that hadronic two-body decays of ψ proceed via the ψ-V (V=ρ, ω, ϕ) mixing and that the strong interactions which induce the ψ→V transition are mediated by gluons. The deviations from the exactSU 3 symmetry in the decays of ψ and the contributions of the amplitudes via the ψ→V transition mediated by a photon are examined semi-phenomenologically by fitting the calculated branching ratios for these decays to the corresponding experimental data. Our results are the following. i) There are sizable deviations (0.3≲β≲0.5) from the exactSU 3 symmetry in the decays of ψ into two-boson final states. They can be understood in terms of the symmetry-breaking effects in the residues of the vector meson poles. ii) The contributions of the amplitudes via the one-photon intermediate state are neither negligibly small nor dominant (|G(u)/E(u)|≈2.8). iii) The relative phase between the amplitudes via the gluon and the one-photon intermediate states is approximately equal to π/2. By using the values of the parameters estimated in this way, the branching ratios for the decays in which the amplitudes via the one-photon intermediate state dominate (in theSU 3 symmetry limit) can be predicted. Γ(f→2γ) is also discussed by using the vector meson dominance hypothesis.

Vector meson production, pion photoproduction, and vector meson dominance

The vector meson dominance hypothesis can be formulated covariantly in terms of invariant amplitudes. This method, which has been successfully used to predict π −p→ ϱ on from pion photoproduction, is extended to include ω production and charged ϱ production. With the introduction of only two further parameters to describe the mass dependence of the ϱωπ coupling, a unified description of vector meson production and pion photoproduction is obtained.

Predictions for ϱ production from pion photoproduction and vector meson dominance

A covariant formulation of the vector meson dominance hypothesis in terms of invariant amplitudes is presented. It is shown that explicit continuation in the external vector mass of the kinematical coefficients relating the invariant and helicity amplitudes allows the prediction of π −p→ ϱ 0n from charged pion photoproduction. Such predictions from a detailed fit to pion photoproduction, with the assumption that the extrapolation of the invariant amplitudes is free from dynamical dependence on the ϱ mass, are shown to be in excellent agreement with the ϱ 0 production data.

Comparison of Orsay results on vector mesons with the vector meson dominance model predictions

Results of the three Orsay experiments are analyzed in the vector meson dominance hypothesis. The coupling constants of ϱo, ωo and φo mesons to the photons are determined, and the mixing angle θ Y and θ N of the ωo and φo mesons are calculated. Our values are compared to various theoretical predictions.

Finiteness of radiative corrections to πβ-decay

We show that the radiative corrections to π-β-decay are finite if a sum rule involving weak and e.m. transitions for π's is satisfied. The sum rule is evaluated in the vector meson dominance hypothesis and found to predict Γ( ω→ πγ) and Γ(− π O → γγ) in good agreement with the experimental data. Some comments are made on the possible general cancellation of the divergences in the radiative corrections to β-decay.