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Showing papers on "Pseudoscalar published in 1974"


Journal ArticleDOI
TL;DR: In this article, a Lagrangian model invariant under supergauge transformations is studied and the relations among masses and couplings are shown to be preserved by renormalization.

1,070 citations


Journal ArticleDOI
TL;DR: In this article, a minimal supergauge invariant extension of quantum electrodynamics is described, which contains a spinor, a scalar and a pseudoscalar field, all charged, plus the photon field and a massless Majorana spinor.

508 citations


Journal ArticleDOI
Sergio Ferrara1, Bruno Zumino1
TL;DR: In this article, Lagrangian theories are constructed which are simultaneously invariant under supergauge transformations and under Yang-Mills transformations, provided the number of scalar supermultiplets is not too high.

390 citations


Journal ArticleDOI
TL;DR: In this paper, the self-consistent equation for fermion propagator in a vector-gluon model is fully examined, and it is proved that with a suitable gauge chosen, the equation without ~utoff has solutions only in the case mo=O, it is then shown that, if g'/4n Bn, the "normal-state" solution without cutoff, even if it existed, should necessarily have an unphysical singularity.
Abstract: Solutions of the self-consistent equation for fermion propagator in a vector-gluon model are fully examined. The equation is characterized by a set of parameters, i.e., the coupling constant g, the bare mass of the fermion mo and the cutoff A. It is proved that with a suitable gauge chosen, the equation without ~utoff has solutions ·only in the case mo=O, It is then shown that, if g'/4n Bn, the "normal-state" solution for the equation without cutoff, even if it existed, should necessarily have an unphysical singularity. This fact implies that the "normal-state" solution becomes unstable for a su.fficiently large value of g'. § l. Introduction The. reason for success of low energy theorems obtained by current algebra and PCAC-treatment may be well understood in terms of chiral symmetry in which the pseudoscalar mesons play a special role among hadtons as the Nambu­ Goldstone (NG) bosons1l transforming nonlinearly under chiral transformation. On the other hand, in the composite hadron models based on SU(3) or SU(6), it is clear that there is no vital distinction between pseudoscalar mesons and others such as vector- and tensor-mesons. It is therefore worth expecting that the pseudoscalar NG bosons can also be interpreted as the bound states in con­ formity with the viewpoint of the composite model. . This homogeneity and· heterogeneity ot the pseudoscalar mesons to other mesons should rather be in­ vestigated by comparing their internal structure with composite particles· . . In this respect it would be meaningful to study a model in which spontaneous breaking of chiral symmetry is realized by a composite NG boson: The Nambu­ Jona-Lasinio model2l is known as such an example. However, the use of chain approximation and the momentum cutoff inevitable for the local four-fermion

106 citations


Journal ArticleDOI
TL;DR: In this paper, it was shown that the weak production of a pion and its subsequent scattering off nucleons leads to effective nuclear renormalizations of the axial current form factors.

63 citations


Journal ArticleDOI
TL;DR: In this article, the possibility of using neutral weak interactions to see whether neutrinos may flip their helicity was explored, and experiments ranging from low-energy neutrino-nucleus scattering to high-energy inclusive reactions were discussed as tests for the presence of helicity-flipping scalar, pseudoscalar and tensor interactions.

44 citations


Journal ArticleDOI
TL;DR: This article showed that the repulsive hard core in the nucleon-nucleon modifies the weak axial form factor g A as well as the pionic form factor G r of the nucleons in nuclear matter.

34 citations


Journal ArticleDOI
TL;DR: In this paper, from simple quark model arguments and assuming a quadratic η − η mixing, the radiative decays of the vector and pseudoscalar mesons were predicted.

32 citations


Journal ArticleDOI
TL;DR: In this article, the pseudoscalar interactions in the two-nucleon (NN) and pionnuclein (πN) systems were discussed in general terms and the equations allowing one to evaluate the 2π exchange contribution to the NN scattering amplitudes and non-relativistic potentials from the knowledge of the corresponding pseudoScalar amplitudes in the πN system were derived.

31 citations


Journal ArticleDOI
TL;DR: In this paper, the Gell-Mann-Okubo formula for the ground-state pseudoscalar octet was shown to be of order e2lne (including η−η′ mixing), where e is a chiral symmetry breaking parameter.
Abstract: Several new results on the breaking of chiral SU(3) × SU(3) are presented within the theoretical framework of chiral perturbation theory. (a) The leading-order corrections to the Gell-Mann-Okubo formula for the baryon octet are shown to be of order e32, where e is a chiral symmetry breaking parameter. An explicit exact expression is given for the leading-order corrections, which provides a new development in understanding why this formula works so well. Similarly the corrections to the Gell-Mann-Okubo formula for the ground-state pseudoscalar octet are shown to be of order e2lne (including η−η′ mixing). On the basis of these exact results it is argued that SU(3) × SU(3) symmetry is as good as SU(3) symmetry ∼30% except when one considers electromagnetic interactions. (b) We examine the η→3π decay on the assumption that it is regulated by a nonelectromagnetic isospinviolating term of the type e3u3 with u3 a member of 3¯3⊕33¯. The strength e3 of this term is related to the experimental rate including all leading-order chiral-symmetry corrections. This estimate of e3 leads to ΔI=1 hadron level shifts about a factor of 2 or 3 too large, although our estimate of e3 depends sensitively on the experimental details. (c) Octet enhancement, an exact formalism to describe η−η′ mixing, and other topics are discussed.

27 citations


Journal ArticleDOI
TL;DR: In this paper, a quantized spin-\textonehalf{}, free-tachyon theory was developed from the Dirac equation using Tanaka's pseudoscalar Lagrangian density.
Abstract: A quantized, spin-\textonehalf{}, free-tachyon theory is developed from the Dirac equation using Tanaka's pseudoscalar Lagrangian density. The tachyon spinors are found with their orthogonality relations. The similarity between the transcendental frame for tachyons and the rest frame for tardyons is noted. Using Fermi-Dirac statistics and including negative-energy states yields a theory which reduces to the four-component neutrino theory in the massless limit. We are able to find only a conserved pseudoscalar, helicity, and a conserved axial vector, related to the energy and momentum of left- and right-handed states. Scalar and polar vector quantities are constructed but are found to either vanish or vary in time.

Journal ArticleDOI
TL;DR: In this article, the possibilities of distinguishing between pseudoscalar (ps) and pseudovector (pv) couplings by an analysis of experimental data on photoproduction and electroproduction processes are discussed.
Abstract: The possibilities of distinguishing between pseudoscalar (ps) and pseudovector (pv) couplings by an analysis of experimental data on photoproduction and electroproduction processes are discussed. It is argued that the charged-${K}^{+}$ electroproduction experimental results may be more reliable for the purpose. It is seen that "Born terms" can explain the qualitative features of some existing data on photo- and electroproduction of $\ensuremath{\pi}$ and $K$ mesons.

Journal ArticleDOI
TL;DR: In this paper, the results of the nonrelativistic quark model can be reproduced by a fully relativistic model of deeply bound spin - 1 2 quarks.

Journal ArticleDOI
TL;DR: In this article, multiplicity distributions of ground state hadrons (pseudoscalar and vector meson nonet and baryon octet and decuplet) are investigated in a model of hadron clusters based of subsequent hadron emission by quarks.


Journal ArticleDOI
TL;DR: In this article, it was shown that the one-pion exchange current renormalizes the axial and induced pseudoscalar form factors of the weak axial current.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the dynamical content of simple nucleon-nucleon dynamics using the Pade approximation, which enjoys unitarity, analyticity and bound-antibounded-state poles, and showed that the one-and two-pion forces are sulficient to reproduce quite well all phase shifts up to 50 MeV, while from 50 MEV to 400 MeV some of the lowest waves still require further improvement.
Abstract: The usual approach to nucleon-nucleon dynamics is based on the potentials derived from the one-boson exchange approximation. Our aim is to investigate the dynamical content of simple. Lagrangians, depending at most on one free parameter, and where the pion is the only source of nuclear forces. Due to the pseudoscalar nature of the pion it is essential to use a fully relativistic formalism: indeed the nucleon negative-parity states, which are taken into account, appear to play a fundamental role especially at zero energy. The inadequacy of the Born series is over-come by applying to the Green's function an approximation (Pade approximation) derived from variational principles; this approximation enjoys unitarity, analyticity and bound-antibound-state poles. The results obtained for the standard Yukawa Lagrangian and the nonlinear σ-model. which fulfils the current algebra constraints, prove that the one- and two-pion forces are sulficient to reproduce quite well all the phase shifts up to 50 MeV, while from 50 MeV to 400 MeV some of the lowest waves still require further improvement. The inversion in theS-waves (the3P0 changes sign) is still lacking but the introduction of the ω-meson in the Lagrangian and inclusion of all possible couplings between physical and unphysical states (some of them were neglected) should provide it.

Journal ArticleDOI
01 Feb 1974-Pramana
TL;DR: Based on the light-cone algebra of currents and pseudoscalar densities, it is suggested in this article that either the high energy meson-nucleon cross-sections are constants (even though the pp-cross-section increases indefinitely) or they deviate from constancy by logarithmic terms whose scale is set by a mass, of the order of at least tens of Gev, and also characterises the consequent log-carithmic violations of Bjorken scaling.
Abstract: Based on considerations of the light-cone algebra of currents and pseudoscalar densities, it is suggested that either the high energy meson-nucleon cross-sections are constants (even though the pp-cross-section increases indefinitely) or that they deviate from constancy by logarithmic terms whose scale is set by a mass, of the order of at least tens of Gev, and which also characterises the consequent logarithmic violations of Bjorken scaling.

Journal ArticleDOI
Bei-Lok Hu1
TL;DR: Anomalous dimensions of tensor operators that determine the Callan-Gross and Corwall-Norton sum rules for the deep inelastic structure functions are calculated to first order in ϵ in the pseudoscalar Yukawa coupling model as mentioned in this paper.

Journal ArticleDOI
01 Nov 1974-Pramana
TL;DR: In this paper, an attempt was made to see how much of chiral symmetry is contained in dual models for pseudoscalar mesons, and the chiral constraints were found to be contained in the dual models as either dynamical restriction or kinematical factors.
Abstract: An attempt is made to see how much of chiral symmetry is contained in dual models for pseudoscalar mesons. The chiral constraints are found to be contained in dual models as either dynamical restriction or kinematical factors. At the phenomenological level there is no serious inconsistency.

Journal ArticleDOI
TL;DR: In this article, the mixing angles of representations are determined from duality constraints with an assumption about the variation of Regge residues, and all the observed pionic couplings are fitted well with one parameter for each helicity.
Abstract: Within the framework of light-like chiral algebra SU (3) i X SU (3), the mixing scheme for meson resonances are investigated. The mixing angles of representations are determined from duality constraints with an assumption about the variation of Regge residues. In parti­ cular, equal-weight mixing between the pseudoscalar and axial vector mesons is obtained. All the observed pionic couplings are fitted well with one parameter for each helicity. Con­ sistency of our results with mass relations of Weinberg's and others is also studied. § I. Introduction

Journal ArticleDOI
TL;DR: In this article, the authors considered the processes of formation of pseudoscalar mesons by the interaction of an antineutrino with a leptonvll → Kπ, ππ, Kππ.
Abstract: The paper considers the processes of formation of pseudoscalar mesons by the interaction of an antineutrino with a leptonvll → Kπ, ππ, Kππ.

Journal ArticleDOI
TL;DR: In this article, a meromorphic amplitude with satisfactory high-energy behaviour and scaling propertics is constructed for the scattering of a current off a pseudoscalar hadron, which has a quark model mass spectrum and factorization properties on the leading trajectory.
Abstract: A meromorphic amplitude with satisfactory high-energy behaviour and scaling propertics is constructed for the scattering of a current off a pseudoscalar hadron. The amplitude has a quark model mass spectrum and factorization properties on the leading trajectory. The current-hadron coupling is mediated by an infinite number of vector mesons and the hadron form factors obtained are satisfactory. The divergence conditions on the amplitude are examined and the possible ways of implementing gauge invariance are mentioned. The light-cone structure of our amplitude is then discussed particularly with respect to the relevance of the light-cone for the derivation of fixed-mass sum rules. It is found that besides the usual singularity there is an additional one associated with the discontinuity on the external current legs. Lastly the conditions for which the quark model relation between the deep inelastic structure functions emerges and the behaviour of the structure functions for ω(=−q2/p·q)→2 are discussed.