Showing papers on "Pseudoscalar published in 1969"
TL;DR: In this paper, the authors consider the model of a spinor field with arbitrary internal degrees of freedom having arbitrary nonderivative coupling to external scalar, pseudoscalar, vector, and axial-vector fields.
Abstract: We consider the model of a spinor field with arbitrary internal degrees of freedom having arbitrary nonderivative coupling to external scalar, pseudoscalar, vector, and axial-vector fields. By carefully defining the $S$ matrix in the interaction picture, the vector and axial-vector currents associated with the external vector and axial-vector fields are found to satisfy anomalous Ward identities. If we require that the vector currents satisfy the usual Ward identities, the divergence of the axial-vector current contains well-defined anomalous terms. These terms are explicitly calculated.
777 citations
35 citations
Journal Article•
34 citations
TL;DR: In this article, the partial rates in the capture of muons by 16O were measured for the Jπ = 0− and 1− excited bound states of 16N and the energy spectrum and the time dependence of the γ-rays emitted by the target were observed using a Ge(Li) detector.
21 citations
TL;DR: The Coulomb coupling of a charged particle suggests that non-analytic terms are present in the Regge theory of photoproduction as discussed by the authors, which provides a natural explanation of the sharp forward peaks observed in charged pion photopsroduction off nucleons.
17 citations
CERN1
TL;DR: In this article, the authors studied the restrictions imposed on a neutral pseudoscalar scattering amplitude by the assumption that the double spectral function is positive and showed that the total cross-section is bounded by const/logs, and that the Froissart-Gribov formula holds forl>1.
Abstract: We study the restrictions imposed on a neutral pseudoscalar scattering amplitude by the assumption that the double spectral function is positive. It turns out that the total cross-section is bounded by const/logs, and that the Froissart-Gribov formula holds forl>1. An example, nearly saturating these limitations, and such that the imaginary part of each partial-wave amplitude is within the unitarity limits, is given.
16 citations
TL;DR: In this paper, the ΔI=1 and ΔI = 2 mass differences of the pseudoscalar and vector mesons, (1/2+) baryon octet and decuplet are examined in the framework of Harari's approach.
Abstract: Starting from the Cottingham formula, the problem of the ΔI=1 and ΔI=2 mass differences of the pseudoscalar and vector mesons, (1/2+) baryon octet and (3/2+) decuplet are examined in the framework of Harari's approach. The Born and the transition terms of all these particles are calculated using a «low frequency» limit which comes essentially from the strong suppression of highq2 values in the Cottingham integral due to the form factors; in this limit we find a «universal» relation between both the electric and the magnetic contributions of the Born terms to the two gauge-invariant parts on the forward spin-nonflip amplitude for the Compton scattering. The residue function of the A2 Regge pole β(q2) is calculated via FESR for the Compton scattering of K-mesons. The application of FESR to (p-n) mass difference is critically examined. The connection with the residues of all the other particles is obtained with the use of the «universality» hypothesis for the coupling of A2 Regge pole with mesons and baryons proposed by Cabibbo, Horowitz and Ne'eman. We find that the inelastic terms thus evaluated give always a contribution of the right sign to the e.m. mass differences. The final numerical results are in striking agreement with experiment.
16 citations
TL;DR: In this paper, the leading order Veneziano model amplitudes for (J P ) 0 − × 0 − → (0 −, 2 +, ) scattering ∗∗ constrained by the absence of “exotic” resonances, is shown to predict the coupling constant relation of SU(3) coupled with the quark-model/SU(6) ideal singlet-octet mixing in the 1 −, 2+, nonets.
12 citations
TL;DR: In this paper, a phenomenological chiral model containing baryons and pseudoscalar mesons was used to calculate the scattering lengths of nucleons in a chiral setting.
Abstract: The $S$-wave ${K}^{+}$-nucleon scattering lengths are calculated in a phenomenological chiral model containing baryons and pseudoscalar mesons. Good agreement with experiment is found, in contrast to the usual current-algebra results which correspond to unphysical limits of our expressions. The sensitivity of the calculation to various modifications of the Langrangian is also discussed. In particular, the scattering lengths are observed to be rather dependent on the way $\mathrm{SU}(3)$ symmetry breaking is introduced into the model.
12 citations
TL;DR: In this article, it was shown that high energy scattering processes which are related by s ↔ u crossing a are similar at a given energy if they are governed by the exchange of Regge trajectories which are exchange degenerate.
TL;DR: In this paper, the Pade method was applied to the S-matrix of the pion-nucleon scattering with the pseudoscalar field theory, and the results of the PAD method due to the first nontrivial approximant and without any phenomenological parameter were in satisfectory agreement with the experimental T = 3/2 phase shifts (S31, P31, D35, D33 and P33, up to roughly 1500 MeV c.m. total energy).
Abstract: The formalism for the application of the Pade method to theS-matrix of the pion-nucleon scattering with the pseudoscalar field theory is introduced. The results of the pseudoscalar pion-nucleon theory due to the first nontrivial approximant and without any phenomenological parameter are in satisfectory agreement with the experimentalT=3/2 phase shifts (S31, P31, D35, D33 andP33, up to roughly 1500 MeV c.m. total energy), except for the width of theP33, which seems related with more involved dynamics than the one considered here. An interesting consistency between the γππ→ππ term in the present problem and the one predicted from the pure boson-boson interaction is achieved. The situation changes in the isospinT=1/2 where the mechanism of absorption with coupled channels and more inelastic contributions (by using approximants of higher order and matrices in two-body channel space) seem necessary to reproduce the strongly absorbed phase shifts.
TL;DR: In this article, the quark model used previously for the construction of couplings of baryons and their resonances (BL) to pseudoscalar mesons is extended to include their couplings also to vector mesons (V) through Schwinger's partial-symmetry method.
Abstract: The general ideas of the quark model used previously for the construction of couplings of baryons (B) and their resonances (BL) to pseudoscalar (P) mesons are extended to include their couplings also to vector mesons (V) through Schwinger’s partial-symmetry method which provides a simple means of relating the VBBL to the PBBL vertices The latter in turn are provided by a semi-relativistic model of brokenSU6×O3 recently proposed by the author through an explicit ansatz for the form factors on the relevant masses, which enables a single parameter to describe an entire supermultiplet transition The model is applied to theNππ modes of severalN- and Δ-type resonances, via theNρ mechanism The results suggest that, analogously to the ω→3π case, anNρ intermediate state, even when energetically forbidden, could still provide an important alternative to the Δπ mechanism forNππ modes
TL;DR: In this article, the value of induced pseudoscalar coupling F P in nuclear μ-capture was studied and the PCAC hypothesis brought about a renormalization of F P due to the form of the pionic propagator in nuclei.
TL;DR: In this paper, the contributions of the cuts in the plane to the photoproduction of pseudoscalar mesons at small angles are evaluated by means of the diagram technique.
TL;DR: In this paper, the parent and the first daughter trajectories of the Veneziano model were investigated in detail and several relations for the VgPSPS and the TgPsPs coupling constants which are equivalent to or consistent with the SU(3) symmetry and Okubo's nonet ansatz were obtained.
Abstract: Crossing·symmetric, Regge behaved amplitudes of the Veneziano type are constructed for Ps-Ps scattering, where Ps denotes the pseudoscalar meson octet. Factorization of the parent and the first (odd) daughter Regge trajectories is investigated in detail. Several relations for the VgPSPS and the TgPsPs coupling constants which are equivalent to or consistent with the SU(3) symmetry and Okubo's nonet ansatz are obtained, where Vg and Tg denote the vector and the tensor meson nonets, respectively. Positive definiteness of the square of the first daughter-Ps-Ps coupling constant leads to inequalities for the trajectories or the masses which are well satisfied by experiment. Factorization condition for the first daughter trajectories leads to trajectory or mass relations which are well satisfied experimentally. In particular the requirement of the universality for the parent and the first daughter p couplings leads to the broken SU(6) mass relations which have bee~ obtained by Kawarabayashi, Kitakado and Yabuki using Adler's PCAC consistency conditions applied to the Veneziano model. Consequences from the requirement of the PCAC conditions on the 1l-meson processes are discussed briefly.
TL;DR: In this article, an extension of the Veneziano model to PS-V elastic scattering is presented, in which the mother Regge trajectory of each family considered has definite parity (both possibilities are considered: natural and unnatural parity dominance) The formulae obtained are then discussed from different points of view: factorization is not trivially satisfied in general, even for mother trajectories; the Adler self-consistency conditions are not automatically fulfilled, but one can impose them by relating the natural and natural parity contributions.
Abstract: An extension of the Veneziano model to PS-V elastic scattering is presented, in which the mother Regge trajectory of each family considered has definite parity (both possibilities are considered: natural and unnatural parity dominance) The formulae obtained are then discussed from different points of view: factorization is not trivially satisfied in general, even for mother trajectories; the Adler self-consistency conditions are not automatically fulfilled, but one can impose them by relating the natural and unnatural parity contributions; as to superconvergence and finite-energy sum rules, they give rise to some difficulties, which, although not specific of the spin case, are increased in this situation
TL;DR: In this article, the strong interaction Hamiltonian is broken from the chiral SU3×SU3 symmetry by scalar densities (u0+cus), wherec is a parameter andu0, us transforms like components of the\(\left( {3.3 } \right) + \left( {\overline 3.3} \right)\) representation.
Abstract: It is assumed that the strong-interaction Hamiltonian is broken from the chiralSU3×SU3 symmetry by scalar densities (u0+cus), wherec is a parameter andu0, us transforms like components of the\(\left( {3.\overline 3 } \right) + \left( {\overline 3 .3} \right)\) representation of the chiralSU3×SU3 group. An assumption of asymptotic symmetry on this scalar and pseudoscalar densities is also made. Calculations are made to correlate the pseudoscalar mesons as well as the much proposed kappa-meson. The η-X mixing problem is also tried.
TL;DR: In this paper, a phenomenological model of relativistic meson and baryon interactions with pseudoscalar mesons is proposed on the basis of broken SU6×O3 through a specific ansatz for the dependence of the form factors on the various masses.
Abstract: A phenomenological model of relativistic meson and baryon interactions with pseudoscalar mesons is proposed on the basis of brokenSU6×O3 through a specific ansatz for the dependence of the form factors on the various masses. The decay widths ofLP=0+, 1−1 and 2+ states for baryons andL=0,1 states for mesons reveal very good agreement with experiment.
TL;DR: In this article, the Veneziano model for meson systems involving axial-vector, vector, pseudoscalar and scalar particles is investigated and the connection between this model and the chiral symmetry is discussed.
TL;DR: In this article, the absorption model is applied to a wide range of mesonbaryons, including meson-baryon, baryon-antibaryon and photoproduction processes at intermediate energies.
Abstract: The absorption model is applied to a wide range of mesonbaryon, baryon-baryon, baryon-antibaryon, and photoproduction processes at intermediate energies.U6,6 is used to uniquely determine the coupling of the exchanged pseudoscalar and vector mesons.
TL;DR: In this paper, the radiative vector and pseudoscalar meson decay widths are calculated using vector-meson dominance model and taking into account ω − Φ and η − X 0 mixings.
TL;DR: In this paper, the possibility of a linear SU-3 mass formula for bosons and consequent non-negligible mixing is considered, and the existence of mixing is indicated by the experimental ratio of the ∆-approximation of the φ ∆ − ∆ 2 ∆ φ − φ 2 φ π ∆ 1 π 2 π φ 1 ∆ Ά 2 Ά 1 − π 1 φ θ 2 ρ 2 2
Abstract: The possibility of a linear ${\mathrm{SU}}_{3}$ mass formula for bosons and consequent non-negligible ${X}^{0}\ensuremath{-}\ensuremath{\eta}$ mixing is considered. The existence of ${X}^{0}\ensuremath{-}\ensuremath{\eta}$ mixing is indicated by the experimental ratio of the ${\ensuremath{\pi}}^{0}\ensuremath{\rightarrow}2\ensuremath{\gamma}$ and $\ensuremath{\eta}\ensuremath{\rightarrow}2\ensuremath{\gamma}$ rates. A phenomenological ${\mathrm{SU}}_{3}$ analysis, with a minimum of dynamical assumptions, of the electromagnetic decay modes $P\ensuremath{\rightarrow}2\ensuremath{\gamma}$, $V\ensuremath{\rightarrow}P+\ensuremath{\gamma}$, and $P\ensuremath{\rightarrow}V+\ensuremath{\gamma}$ is made with the purpose of distinguishing between the linear and quadratic mass formulas.
TL;DR: In this paper, the massive gauge field is shown to be the Lagrangian equivalent of a composite massless field containing pseudoscalar as well as vector components, which is the case in the special case of the privileged gauge.
TL;DR: In this article, the absorption model is applied to photoproduction processes at intermediate en energies assuming vector dominance, and U(6,6) is used to uniquely determine the couplings of the exchanged pseudoscalar and vector mesons.
TL;DR: In this article, the Pγγ couplings g P γγ (k 2 = − m P 2 ) are shown to contain two terms: one dependent on the charge of the fundamental triplet and the other linear in the square of the meson masses.
TL;DR: In this paper, the first-order SU(3) symmetry breaking in semi-leptonic decays is studied by use of the techniques of equal time commutators, and the correction for the baryon axial-vector decay constants is related to that for the strong derivative coupling constants of pseudoscalar meson-baryon interaction.
TL;DR: In this article, a multichannel dynamical calculation of pseudoscalar and axial vector meson parameters is performed using the relativistic Lippmann-Schwinger equation.
Abstract: : A multichannel dynamical calculation of pseudoscalar and axial vector meson parameters is performed using the relativistic Lippmann-Schwinger equation. The channel considered is PV to PV. The potential is computed using the usual Feynman rules and the resulting equations are solved on a computer. The cut-off is fixed by adjusting the output mass of one resonance or bound state or the output width to the experimental value. (Author)