Showing papers on "Meson published in 1969"
TL;DR: In this paper, the decay rates of spin 2+, 1+ and 0+ mesons were calculated in a quark rearrangement model with L excitation for the meson resonances.
422 citations
TL;DR: In this article, the Veneziano model for the binary meson reaction (n = 4), generalized by Bardakci and Ruegg and by Virasoro to n = 5, is further extended to the case of arbitrary n. The multi-resonance structure of the n-meson reaction is analyzed with the help of quark diagrams.
180 citations
CERN1
TL;DR: In this article, it was shown that the existence of very tightly bound states with a nonrelativistic spinor structure requires a Dirac scalar potential (or sum of irreducible graphs) as well as small internal three momentum (q2 ⪡ MQ2).
175 citations
173 citations
TL;DR: In this paper, a vector-meson dominance model for high energy inelastic scattering is proposed and the ratio of the longitudinal to the transverse cross section is given by Θ(n 2.5 BeV ) for high values of the missing mass.
Abstract: A vector-meson dominance model for high-energy $\mathrm{ep}$ inelastic scattering is proposed. We predict that at high values of the missing mass (g2.5 BeV) the ratio of the longitudinal to the transverse cross section is given by $\ensuremath{\xi}(\frac{{q}^{2}}{m_{\ensuremath{\rho}}^{}{}_{}{}^{2}}{[1\ensuremath{-}(\frac{{q}^{2}}{2{m}_{p}\ensuremath{
u}})]}^{2}$, where $\ensuremath{\xi}$ is expected to be of the order of unity. Scale invariance (in the sense of Bjorken) is satisfied at very high ${q}^{2}$. The model may adequately account for the remarkably large cross section recently observed in the deep inelastic region.
139 citations
TL;DR: In this article, an integral representation of the generalized Veneziano amplitude for the n -meson reaction is constructed in such a way that all the external mesons appear on an equal footing and thus all the requirements of crossing symmetry are fulfilled.
134 citations
TL;DR: Veneziano-type amplitudes for ππ, πK, KK and KK scattering are constructed and normalized at the ϱ pole in this paper, and S-wave scattering lengths are calculated in good agreement with those obtained by the method of current algebra.
65 citations
01 Jan 1969
65 citations
TL;DR: In this article, a vector-meson dominance model for diffractive electroproduction of vector mesons at high energies is presented, where the assumption that the invariant amplitudes are slowly varying as a function of the vector meson mass, when extrapolating to the spacelike region, is shown to lead to serious difficulties when combined with helicity independence.
52 citations
TL;DR: In this paper, a general procedure for constructing the scattering amplitudes of hadrons with external currents was proposed, which is obtained from a representation of the N-point function for hadrons and leptons, in the lowest order of the weak constant.
Abstract: We propose a general procedure for constructing the scattering amplitudes of hadrons with external currents. These are obtained from a representation of theN-point function for hadrons and leptons, in the lowest order of the weak constant. We consider a model with external scalar mesons and vector currents only. Current conservation is not required. We study the form factor, electroproduction and Compton scattering finding good analytic properties for the amplitudes.
TL;DR: In this article, the absolute differential cross section for photo-production of neutral rho mesons from complex nuclei at a photon energy of 8.8 BeV was measured using a two-parameter optical model.
Abstract: We have measured the absolute differential cross section for photo- production of neutral rho mesons from complex nuclei at a photon energy of 8.8 BeV. Using a two-parameter optical model, we have de- duced a value for the total rho-nucleon cross section of (30 f i) mb. Application of the Vector Dominance Model results in a value for the 'rho photon coupling of yi /47r = 1.1 * 0.2.
TL;DR: In this paper, it was shown that information about the nuclear electromagnetic transition vertex derived from experimental inelastic-scattering cross sections for electrons may be used to evaluate the nuclear-polarization (dispersion) corrections to the levels of muonic atoms.
Abstract: It is shown that information about the nuclear electromagnetic-transition vertex derived from experimental inelastic-scattering cross sections for electrons may be used to evaluate the nuclear-polarization (dispersion) corrections to the levels of muonic atoms. A model-independent result is obtained for the contributions of discrete nuclear states. The most important systematic features of nuclear-excitation spectra, the giant-dipole resonance and the quasielastic peak, are considered in detail. The Goldhaber-Teller model is used for the former, and a simple-harmonic-oscillator shell model for the latter. Numerical estimates are obtained for total level shifts of low-lying muon states in nuclei with closed (harmonic-oscillator) proton shells, using closure approximation for the muon. The muon closure energies are considered in detail. It is felt that the results obtained are probably accurate to a factor of 2. The shifts are estimated to be several keV for the $1s$ state in heavy nuclei, and somewhat less (a few tenths to about 1 keV) for the $2s$ and $2p$ states. These shifts are significant in comparison to the present accuracy of measurement of muonic x-ray spectra, and should be considered in calculations to fit nuclear-charge distributions.
TL;DR: In this article, the results of the three Orsay experiments were analyzed in the vector meson dominance hypothesis and the coupling constants of ϱ o, ω o and φ o mesons to the photons were determined.
TL;DR: The implications of vector dominance for the optical properties of complex nuclei are examined in this article, with particular attention paid to the transition from the low-energy regime where the nucleus acts as a transparent object to the high energy regime, where the photonuclear cross sections have some of the characteristics of shadow scattering.
Abstract: The implications of vector dominance for the optical properties of complex nuclei are examined. Particular attention is paid to the transition from the low-energy regime where the nucleus acts as a transparent object to the high-energy regime where the photonuclear cross sections have some of the characteristics of shadow scattering. This transition occurs in the energy range available to existing accelerators. The energy dependence of total photoabsorption and inelastic cross sections are calculated and found to be appreciable; they are therefore amenable to experimental study.
TL;DR: In this paper, the photoproduction of mesons from hydrogen and deuterium was measured as a function of the photon energy, and the square of the momentum transfer, and it was shown that the assumption that the mesons are produced by a purely diffractive mechanism is midly contradicted by the data.
Abstract: We have measured the photoproduction of ${\ensuremath{\rho}}^{0}$ mesons from hydrogen and deuterium as a function of the photon energy, ${k}_{\ensuremath{\gamma}}$, and the square of the momentum transfer, $t$. The assumption that the $\ensuremath{\rho}$ is produced by a purely diffractive mechanism is midly contradicted by the data.
TL;DR: In this article, the authors discuss the electromagnetic ϱ-ω mixing in the light of recent experimental data in the ω → 2π transition and discuss the effect of the φ → φ transition on the mixing of the electromagnetic signal.
TL;DR: In this article, a field-theoretic model of the exchange of virtual soft neutral vector mesons between nucleons is shown to provide the needed damping to describe elastic scattering and the electromagnetic form factors of the proton at high energies and large momentum transfers.
Abstract: A field-theoretic model of the exchange of virtual soft neutral vector mesons between nucleons is shown to provide the needed damping to describe $\mathrm{pp}$ elastic scattering and the electromagnetic form factors of the proton at high energies and large momentum transfers. The model permits a calculation of the infinite-energy limit of $\mathrm{pp}$ scattering, and suggests that $p\overline{p}$ scattering will rise to that limit at very high energies.
TL;DR: In this article, Veneziano's model was generalized to the five-point function and the coupling constants of exchanged resonances were deduced for the processes K K → 3π and K K to K K π, and the results are partial SU(3), ωφ and ff′ mixing angles.
TL;DR: In this paper, the conditions imposed on Regge trajectories by requiring flat total cross sections for all reactions in 'exotic' channels are systematically investigated under very general conditions, and a quark model with universal U(3) symmetry is shown to be the unique solution consistent with broken SU(3), having flat exotic total cross-sections for meson-meson scattering.
CERN1
TL;DR: In this paper, the decay angular distribution of K+p→ Kππ has been investigated in the CERN 2 m and Saclay 81 cm hydrogen bubble chambers and the cross-sections for the various final states contributing to these reactions have been determined.
Abstract: Among the interactions of K+p at 5 GeV/c produced in the CERN 2 m and Saclay 81 cm hydrogen bubble chambers we have studied the four-body reactions K+p→ Kππ. The cross-sections for the various final states contributing to these reactions have been determined. A detailed analysis has been performed on the double-resonance production K+p→ K*(892)*(1236). Decay angular distributions for both resonances have been studied and single and joint spin-density matrix elements calculated as a function of four-momentum transfer. The results have been compared to the absorption-model predictions assuming pion exchange. Various quark-model predictions for the decay angular distributions have been tested. The quark-model relations derived on the basis of the additivity assumption only, are experimentally well satisfied. If additional conditions about the quark-quark scattering amplitudes are imposed, only some of the quark-model predictions agree with experiment.
CERN1
TL;DR: In this paper, the longitudinal phase-space analysis is applied to various three-body final states of meson-nucleon collisions at 5 −16 GeV/c primary momentum.
TL;DR: In this article, the authors analyzed 17,000 four-prong annihilations of 1.2 GeV/c antiprotons in hydrogen and considered those events with one neutral pion (5π), showing production of ϱ 0, ϱ ±, f 0, ω 0, η 0 mesons.
TL;DR: In this article, the validity of various vector-meson dominance relations for single-pion photoproduction was examined within the framework of the electric Born model and its hadronic analog.
TL;DR: In this article, the ππ scattering length and low-energy phase shifts are tabulated corresponding to various assumptions on the mass and width of the sigma meson using forward and first derivative dispersion relations.