Showing papers on "Meson published in 1975"
TL;DR: In this paper, the masses and static parameters of the light hadrons (the pseudoscalar and vector meson nonets and the baryon octet and decuplet) are calculated using the bag model.
Abstract: The masses and static parameters of the light hadrons (the pseudoscalar and vector meson nonets and the baryon octet and decuplet) are calculated using the bag model. The effects of quark kinetic energy, bag energy, strange-quark mass, colored-gluon exchange in lowest order, and energy associated with certain quantum fluctuations are included. These are parameterized by four constants which have fundamental significance and do not change from multiplet to multiplet. The fit to the spectrum is good. The ordering of all the states is given correctly. The intramultiplet splittings are very accurate for the baryon decuplet and reasonably good for the other multiplets. The isosinglet pseudoscalar mesons eta and eta' are treated separately in light of the special role that gluon intermediate states play in these states. Magnetic moments, weak decay constants, and charge radii are calculated. Where comparison with experiment is possible, we generally obtain improvement over the naive quark model. It is shown that exotic baryons do not exist as narrow resonances in this approximation to the bag theory. (AIP)
717 citations
TL;DR: In this article, it was shown that a quark carrying nearly all the momentum of a nucleon (x≈1) must have the same helicity as the nucleon, and the resulting angular dependence for e^(+)e^(-)→h^(±)+ X is consistent with present data.
Abstract: In a colored-quark and vector-gluon model of hadrons we show that a quark carrying nearly all the momentum of a nucleon (x≈1) must have the same helicity as the nucleon; consequently νW^2_n/νW^p_2→(3/7) as x→1, not (2/3) as might naively have been expected. Furthermore as x→1, νW^(π)_2∼(1-x)^2 and (σ_(L)/σ_(T))π∼μ^(2)Q^(-2)(1-x)^(-2)+O(g^2); the resulting angular dependence for e^(+)e^(-)→h^(±)+ X is consistent with present data and has a distinctive form which can be easily tested when better data are available.
309 citations
TL;DR: In this article, the Zweig rule for meson decays and the decays of the Ψ-resonances are discussed, depending on the various possibilities for the spectrum of the glue mesons.
Abstract: On the basis of the quark-gluon field theory we discuss the dynamical manifestations of gluons in hadron physics. Especially we concentrate on the Zweig rule for meson decays and the decays of the Ψ-resonances. Depending on the various possibilities for the spectrum of the glue mesons, we describe both the glue annihilation and the mixing mechanism for the Zweig-rule-violating meson decays. Furthermore we discuss the break-down of PCAC for the pseudoscalar analogue of the Ψ-meson and the importance of the glue mixing term for the mass spectrum of the pseudoscalar mesons.
209 citations
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TL;DR: In this article, it was shown that the newly discovered narrow resonance at 3.1 GeV is a state of charmed quarks, and the consistency of this interpretation with known meson systematics was established.
Abstract: We argue that the newly discovered narrow resonance at 3.1 GeV is a $^{3}S_{1}$ bound state of charmed quarks and we show the consistency of this interpretation with known meson systematics. The crucial test of this notion is the existence of charmed hadrons near 2 GeV.
190 citations
TL;DR: In this article, the authors estimate the masses and decay rates of these states and emphasize the importance of γ-ray spectroscopy for the detection of quark-antiquark bound states.
Abstract: The interpretation of the narrow boson resonances at 3.1 and 3.7 GeV as charmed quark-antiquark bound states implies the existence of other states. Some of these should be copiously produced in the radiative decays of the 3.7-GeV resonance. We estimate the masses and decay rates of these states and emphasize the importance of γ-ray spectroscopy.
161 citations
CERN1
TL;DR: Several arguments for the dominance of certain types of non-leptonic weak decays of hadrons are examined for their applicability to high-mass hadrons in this paper, based on asymptotic freedom, duality, current algebra and PCAC.
131 citations
CERN1
TL;DR: In this paper, the 3 S 1 S mass separations of the bound quark-antiquark systems, arising from one-gluon exchange, in the charm color quartet scheme, are discussed for the ground mesons and their first radial excitations expecially in connection to leptonic decay rates.
113 citations
TL;DR: In this paper, the nucleon-nucleon interactions obtained from several models for the field theoretic scattering amplitude are studied and the resulting interaction is regularized by a cut-off factor obtained by the eikonal approximation to multiple vector meson exchange processes.
102 citations
TL;DR: In this article, a phase shift analysis of K + p and K + d data in the region below 1.5 GeV/ c kaon lab momentum is presented for isospin I = 0 and 1.
99 citations
TL;DR: In this article, a simple relativistic potential model is constructed in order to describe meson spectroscopy in a unified way, encompassing both light and heavy quark systems, and a linear potential, transforming as the fourth component of a vector potential, is assumed in accordance with quark-confinement mechanisms appropriate to gauge theories.
Abstract: A simple relativistic potential model is constructed in order to describe meson spectroscopy in a unified way, encompassing both light- and heavy-quark systems. A linear potential, transforming as the fourth component of a vector potential, is assumed in accordance with quark-confinement mechanisms appropriate to gauge theories. Scaling arguments are used to derive the Regge behavior of the model. We present evidence that the forces which confine quarks are essentially independent of quark species. The over-all systematics of our predictions for meson energy levels and leptonic decay widths give support to the usefulness of the model. We comment on the application of asymptotic freedom as a means of estimating decay rates which violate the Okubo - Zweig - Iizuka rule.
83 citations
TL;DR: In this paper, the photoproduction of the psi (3100) meson from a beryllium target has been measured using an 11.8-GeV bremsstrahlung beam.
Abstract: The photoproduction of the psi (3100) meson from a beryllium target has been measured using an 11.8-GeV bremsstrahlung beam. The energy and angular dependence of the measured spectra may be obtained from an elastic nucleon cross section of the form dsigma/dt= (1.01plus-or-minus0.20) exp(1.25plus-or-minus0.20) t nb/GeV$sup 2$. This cross section is exceedingly small in comparison with those of the other vector mesons. (AIP)
TL;DR: In this paper, the authors assign ψ(3695) to an exotic meson cc(pp+nn) and ψ (3105) to a vector meson CC, respectively.
Abstract: We assign ψ(3695) to an exotic meson cc(pp+nn) and ψ(3105) to a vector meson cc, respectively. Then we can explain naturally two facts: 1) ψ(3695) decays strongly to ψ(3105) + 2π and 2) there is very little ψ(3695) production compared with ψ(3105) production in pN scattering at Brookhaven. In this model we expect two broad resonances at 3.7 ∼4.1 GeV and at ∼4.1 GeV. We also predict another resonance at ∼6.2 GeV, which will be a sharp resonance if the mass is smaller than twice the mass of the lowest mass state of cc.
TL;DR: In this article, the leading particle spectrum of non-diffractive hadron-hadron collisions is linked to the x distribution of quarks in the hadron, as deduced from the structure functions measured in deep inelastic scattering of electrons and neutrinos on nucleons.
TL;DR: In this article, the Coulomb exchange kernel was used to resolve the discrepancy between the potential tail for the S, D and G waves and that for higher partial waves which was reported in a previous phenomenological analysis, but hardly understandable from a microscopic point of view.
Abstract: Intermediate energy a-a scattering is studied by the resonating group method with the Coulomb exchange kernel, in order to resolve the discrepancy between the potential tail for the S, D and G waves and that for higher partial waves which was reported in a previous phenomenological analysis_ but hardly understandable from a microscopic point of view. It is shown that this discrepancy can be removed if we employ the new solution of the pha;;e shift analysis. Validity of the orthogonality condition model in the inelastic region is shown if a suitable imaginary potential ·is added to the direct potential. The real phase shifts of the !-wave dominated by the direct potential tail restrict the coupling constants of isoscalar mesons with nucleon as g62/4n=3.5~6 and g.'/4n=8~11.
TL;DR: In this paper, double differential cross sections for deuteron electrodisintegration near threshold from back-scattered electrons were calculated for electron four-momentum transfer squares in the range 0 Δ2 ⩽ 15 fm−2 and for final n-p relative energies in range 0 ⌈ Erel ⌽ 15 MeV using the Reid hard-core parametrization of the n p potential.
TL;DR: In this article, relations among various two-body channels in weak decays of charmed hadrons are worked out in the framework of the four-quark model of the weak interactions.
Abstract: SU(3) relations among various two-body channels in weak decays of charmed hadrons are worked out in the framework of the four-quark model of the weak interactions. Effects analogous to ${K}^{0}$, ${\overline{K}}^{0}$ mixing are discussed for charmed mesons. A certain dominance possibility, analogous to octet dominance for charm-conserving weak reactions, is noted.
TL;DR: In this paper, the transverse momentum spectrum of π0's produced at c.m. angles θ = 90° and 53° in pp collisions at √s = 23.6, 30.8, 45.1, 53.2, and 62.9 GeV.
TL;DR: In this paper, a phase diagram describing the ground state of infinite nuclear matter as a function of baryon density was derived for the linear sigma model, and it was shown that a phase transition to a pion-condensate ground state occurs in a macroscopic system such as a neutron star at high baryone density.
Abstract: The successes of current algebra and partial conservation of axial- vector current can be interpreted as indications that the strong interactions are approximately symmetric under chiral Su(2) times SU(2) transformations In the absence of matter, the explicit chiral-symmetry breaking defines a unique vacuum state for the theory The smallness of the chiral-symmetry breaking, however, implies the existence of many other states, approximately degenerate in energy with, but orthogonal to, the true vacuum In these states, in general does not equal 0; thus they contain a ''pion condensate'' In a macroscopic system - such as a neutron star - at very high baryon density one of these pion- condensed states might become the true ground state We study this phenomenon in the linear sigma model We are able to calculate analytically the ''phase diagram'' describing the ground state of infinite nuclear matter as a function of baryon density Above a critical baryon density a phase transition to a pion- condensed ground state occurs We extend the chiral-symmetry approach to include the effects of the N* (1236) and the ill-understood $gamma$-N s waves In addition to analyzing the ground state, we examine the spectrum of excited states In themore » condensed phase, the meson excitation spectrum contains a ''Goldstone boson'' associated with the ground state's not being an eigenstate of the conserved operator I$sub 3$ However, when electromagnetic interactions are included, this mode disappears via the Higgs phenomenon indicating that the ground state is a superconductor The presence of the pion condensate fosters the $beta$ decay of the fermion excitations, and the emitted neutrinos provide the cooling mechanism for neutron stars« less
TL;DR: A Coulomb type potential between light quark-antiquark pair for separation distances r ⩽ b 0, is found to provide satisfactory values of the pion form factor in agreement with experiments as discussed by the authors.
TL;DR: In this article, the authors proposed a new quark model for the hadron spectrum, consisting of six quarks -the usual triplet and a new antitriplet of heavy quarks, with electric charges + 2 3, + 1 3,− 1 3.
TL;DR: In this article, an SU(5) model for the new heavy mesons was proposed, with a charge −1 3 fancy quark in addition to a charge +2 3 charmed quark.
Abstract: Using a generalization of the $|\ensuremath{\Delta}I|=\frac{1}{2}$ rule, we analyze the nonleptonic weak decays of pseudoscalar charmed mesons. We call attention to the likelihood that the dominant decays will be into many-body channels. Special attention is devoted to the properties of charmed final states just above charm threshold in ${e}^{+}{e}^{\ensuremath{-}}$ annihilation. The questions of charged multiplicity, copious kaon production, and energy carried by neutrals are explored.
TL;DR: The structure of theories which attempt to describe composite hadrons by means of quark field variables defined on a light plane, can be probed using the transformation properties of observables with respect to the light-plane charges as mentioned in this paper.
TL;DR: In this article, the threshold conditions for a phase transition to a negative pion condensate in neutron matter were studied, where the Δ isobar was allowed to enter as an intermediate particle in the polarisation bubbles of the curent-current correlation function.
TL;DR: In this paper, the authors discuss various weak-interaction issues for a general class of models within the SU(2) x U(1) gauge-theory framework, with special emphasis on the effects of right-handed charged currents and of quarks bearing new quantum numbers.
Abstract: We discuss various weak-interaction issues for a general class of models within the SU(2) x U(1) gauge-theory framework, with special emphasis on the effects of right-handed charged currents and of quarks bearing new quantum numbers. In particular we consider the restrictions on model building which are imposed by the small K/sub L/--K/sub S/ mass difference and by the $delta$I = 1/2 rule, and we classify various possibilities for neutral current interactions and, in the case of heavy mesons with new quantum numbers, various possibilities for mixing effects analogous to K/sub L/--K/sub S/ mixing. (AIP)
TL;DR: In this article, the production of high transverse momentum mesons from proton-proton collisions has been studied at the CERN ISR and the decay η→γγ was identified in an array of lead-glass Cerenkov counters.
TL;DR: In this paper, the authors investigated the hadronic spectroscopy of a linear confining potential acting between quarks and showed that the decreasing spacing between radially excited states of a given orbital angular momentum has substantial support in both meson and baryon spectra.
Abstract: We investigate the hadronic spectroscopy of a linear confining potential acting between quarks. The resulting systematics are quite satisfactory. In particular the decreasing spacing between radially excited states of a given orbital angular momentum has substantial support in both meson and baryon spectra.