Showing papers on "Pseudoscalar published in 1973"
TL;DR: In this paper, a study of 620 hadron pairs produced in the s -range (1.44−9.0) GeV 2, has yielded 110 collinear hadronic events.
49 citations
TL;DR: In this paper, a skew-symmetric field and its dual field are quantized by requiring Lorentz invariance and the positive definiteness of the Hamiltonian, and the lowest-order Lagrangians may be derived from a generally covariant Lagrangian for the gravitational field, previously proposed by Nakano and the author.
37 citations
TL;DR: In this article, the second-class current (scc) contribution to asymmetries in nuclear mirror Gamow-Teller decays is calculated, taking into account both off-mass-shell and meson-exchange effects.
28 citations
TL;DR: In this paper, the partial muon capture rates on 16 O leading to all four particle-stable states in 16 N have been measured and the results obtained are compared to previous measurements and are also used to extract a value for the induced pseudoscalar coupling constant in Muon capture.
21 citations
TL;DR: In this paper, a combined analysis of low-energy nucleon-nucleon and hyperon nucleon scattering was performed to determine some of the parameters of the scalar-meson nonet.
Abstract: In a combined analysis of low-energy nucleon-nucleon and hyperon-nucleon scattering we have determined some of the parameters of the scalar-meson nonet. We find that the $\ensuremath{\epsilon}$ meson is dominantly a unitary singlet. Simultaneously, we obtain good values for the $\frac{F}{(F+D)}$ ratios and coupling constants for the pseudoscalar and vector mesons.
19 citations
TL;DR: In this article, the relativistic corrections were obtained from the approximately relativistically invariant (to within terms in v2/c2) Breit-type equation for two nucleons.
Abstract: It is shown that the observed spin-orbit splittings in the atomic nuclei may be explained theoretically if one takes into account the relativistic character of the nucleon motion in the bound many-nucleon system. The relativistic corrections were obtained from the approximately relativistically invariant (to within terms in v2/c2) Breit-type equation for two nucleons. Two-particle interactions were taken in the form of one-boson-exchange potentials which reproduce well the nucleon-nucleon scattering data and which include pseudoscalar, scalar and vector mesons and resonances. The calculations of the doublet splittings of different single-particle levels in 41Ca and 209Pb were carried out, the values of the nuclear average field being calculated as well. Agreement with experiment is reasonably satisfactory.
8 citations
TL;DR: In this paper, the meson exchange diagram and the longest range part of a two-nucleon electromagnetic operator were obtained for the radiation of a real photon and the multipole expansions of the transition operators were obtained.
8 citations
TL;DR: In this paper, the photoproduction of pseudoscalar mesons is investigated in the framework of a dual-B5-model with fixed and Regge poles, and a reasonable fit to the available high-energy forward scattering data is presented which is characterized by essentially three parameters.
Abstract: The photoproduction of pseudoscalar mesons is investigated in the framework of a dualB5-model with fixed and Regge poles. A reasonable fit to the available high-energy forward scattering data is presented which is characterized by essentially three parameters. The values of the Regge residues for natural- and unnatural-parity exchanges agree with the values obtained in other photoproduction models. The photoexcitation features of the low-lying baryon resonances derived from our model are in qualitative agreement with experimental results.
7 citations
TL;DR: In this article, a baryon-antibaryon bootstrap model for the meson spectrum is presented, where the forces are constructed from thet-channel singularities of the nearest meson multiplets and transformed into an SU3 symmetric potential.
Abstract: In this work we present a baryon-antibaryon bootstrap model which, for the meson spectrum, we understand to be an alternative of the quark model. Starting from the baryon octets, the forces are constructed from thet-channel singularities of the nearest meson multiplets and transformed into anSU3 symmetric potential. At this stage we assume that the baryon and meson multiplets are degenerate. Any contributions from theu-channel are neglected for it is exotic and only contains the deuteron. The dynamical equation governing the bootstrap system is the relativistic analogue of the Lippmann-Schwinger equation which is an integral equation in the baryon c.m. momentum. The potential is chosen to take account of relativistic effects. Inelastic contributions such as two-meson intermediate states are neglected. Reasons why they must be small are discussed. We are looking for a self-consistent solution of the bootstrap system in which baryon-antibaryon bound-state multiplets, to be interpreted as mesons, are forced to coincide with the input meson multiplets. Furthermore, the output coupling constants andF/D ratios have, to a certain extent, to agree with their input values. Practically, it is required that the bootstrap system consists of only a few multiplets, the remainder being decoupled approximately. A self-consistent solution is found comprising scalar, pseudoscalar and vector singlets and octets with masses being in good agreement with their average physical masses. The coupling constants andF/D ratios turn out to be consistent with experiment and other ideas. Possible origins ofSU3 breaking are then investigated. The spontaneous break-down ofSU3 is ruled out by the fact that the dynamics is stable against small perturbations of the input masses. Instead, a solution of the symmetry breaking is given in terms of bootstrapped singlet-octet mixing.
5 citations
TL;DR: In this paper, the Lagrangian chosen is of nonpolynomial character and a quantitative formula (eq. (12)) is obtained for the massive superpropagator, showing that the amplitude so derived in the high-energy approximation behaves in accordance with experiment.
Abstract: The divergences in QFT are not a consequence of an inadequate treatment of the perturbation expansion, but a consequence of an inadequate choice of the Lagrangian. In this work the question is studied in the case of the elastic scattering of two fermions, with the exchange of a given number of vector mesons and of an increasing number of scalar or pseudoscalar mesons. The Lagrangian chosen is of nonpolynomial character and a quantitative formula (eq. (12)) is obtained for the massive superpropagator. It is shown that the amplitude so derived in the high-energy approximation behaves in accordance with experiment. It is thought that it will be the basis also for developments in inelastic processes.
5 citations
TL;DR: In this article, the effect of finite nuclear size on the induced pseudoscalar term was investigated and it was found that it is important to account for the difference between the PCAC value for this term and the values necessary to understand recent muon capture experiments in 16 O and 40 Ca.
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TL;DR: In this article, the authors discuss the available experimental evidence on η-η′ mixing in an attempt to decide between the linear and quadratic schemes and conclude that linear mixing is not ruled out by high-energy production experiments.
TL;DR: In this paper, the effective bare masses of the current quarks are estimated from some testable inequalities, linking deep inelastic lepton nucleon structure functions and high energy meson-nucleon total cross-sections, derived on the basis of the light-cone commutators of the pseudoscalar densities of quark field theory.
TL;DR: In this article, the structure of Wick-rotated spinor-spinor Bethe-Salpeter equations is studied in coordinate space, and the interaction includes ladder-like contributions of scalar, pseudoscalar, vector and axialvector mesons.
TL;DR: In this paper, the authors considered the photo-production of pseudoscalar and vector mesons in the high energy region and derived the amplitudes for the photoproduction of mesons.
TL;DR: In this article, the contribution of the leading light-cone singularities to the total cross sections for r·hadron and vector meson-hadron collisions is studied by applying the Fourier transforma· tion with time-like momenta to the known part of the current commutator function near the lightcone.
Abstract: The contribution from the leading light-cone singularities to the total cross sections for r·hadron and vector meson-hadron collisions is studied by applying the Fourier transforma· tion with time-like momenta to the known part of the current commutator function near the light-cone. The spectral function introduced in the modified causal function is favoured to have a broad spectrum with a finite support. A similar analysis is· also made for pseudoscalar meson-hadron collisions. In all cases, the contribution has a common form of structure functions times the spectral function and represents a major part of the continuum in the non diffractive component. Based on this result, a unique division of the non-diffractive component into the continuum and the resonance-dominated part is suggested in contrast to the duality approach.
TL;DR: In this paper, a gauge-invariant regularization of a massive spinor field interacting with external scalar, pseudoscalar, vector and axial fields is found based on ϵ separating the vertices in the total Lagrangian.
TL;DR: In this paper, a general charge-dependent correction to the two-nucleon interaction due to the electromagnetic mass differences of the I=1, scalar, pseudoscalar and vector mesons is evaluated.
Abstract: A general charge-dependent correction to the two-nucleon interaction due to the electromagnetic mass differences of theI=1, scalar, pseudoscalar and vector mesons is evaluated. TheLS andS12 terms which arise from scalar-, pseudoscalar- and vector-meson exchanges have also been taken into account. An effective charge-dependent two-nucleon potential with a Yukawa radial dependence is obtained by a least-squares fit to the charge-dependent potential arising from the ρ-meson electromagnetic mass difference. The parameters which measure the derivation from charge independence in the Blin-Stoyle and Le Tourneux potential is calculated by a simple comparison. The observed discrepancies between the neutron-proton and proton-proton scattering lengths and effective ranges in the singletS-state are examined in terms of this potential. The Coulomb and vacuum polarization potential correction to the proton-proton effective range also shows a small difference from the neutron-proton effective range. In order to obtain agreement between neutron-proton and proton-proton scattering lengths and effective ranges we find that the electromagnetic mass difference of ρ-mesons, Δϱ=ϱ+−ϱ0, must lie between −1.8 and −9.0 MeV for various OBEP model parameters.
01 Apr 1973
TL;DR: In this paper, the two-body production amplitudes for Y=1 exchange reactions are discussed and the Quark model, SU(3), and VDM comparisons are made and the EXD nature of the K** and K* Regge exchanges explored.
Abstract: The determination of the two‐body production amplitudes for Y=1 exchange reactions is discussed. The pseudoscalar production line reversed reactions K−n ⇒ π−Lgr; and π−p ⇒ K0Λ; the vector‐meson production reactions K−p ⇒ (ω,φ)Λ and π−p ⇒ K*0Λ; the reaction K−p ⇒ π−Y*+(1385); and the photoproduction reaction γp ⇒ K+Λ are examined. Quark model, SU(3), and VDM comparisons are made and the EXD nature of the K** and K* Regge exchanges explored. In addition the behavior of the unnatural parity Y=1 exchanges (K, KB, KA) are investigated
TL;DR: In this article, a nonlinear Lagrangian is constructed to describe the scalar and pseudoscalar mesons such that the chiral SU(3) \ifmmode\times\else\texttimes\fi{} SU( 3)-symmetry is realized by an octet of Goldstone pseudo-calars.
Abstract: We construct a nonlinear Lagrangian to describe the scalar and pseudoscalar mesons such that the chiral SU(3) \ifmmode\times\else\texttimes\fi{} SU(3) symmetry is realized by an octet of Goldstone pseudoscalar mesons while the scalar particles behave neither as parity partners of the pseudoscalar mesons nor as Goldstone bosons in the SU(3) \ifmmode\times\else\texttimes\fi{} SU(3)-symmetry limit. The symmetry-breaking Lagrangian is assumed to transform as the $(3,\overline{3})+(\overline{3},3)$ representation of the SU(3) \ifmmode\times\else\texttimes\fi{} SU(3) group and contain explicit SU(3) - and SU(2)-violating terms. The transformation properties of the scalar fields together with these breaking terms in the Lagrangian enable our model to have an SU(3) -broken vacuum. We exhibit the masses of the scalar and pseudoscalar particles as well as the decay constants defining PCAC (partial conservation of axial-vector current) and PCVC (partial conservation of vector current) relations in terms of the parameters of the model, and obtain various well-known relationships (including the Glashow-Weinberg sum rules) between the physical quantities. The smoothness assumption is shown to imply approximate SU(2) \ifmmode\times\else\texttimes\fi{} SU(2) symmetry of the Lagrangian with a small SU(3) violation in the vacuum (Gell-Mann-Oakes-Renner model), while an appropriate change in the smoothness assumption leads to approximate SU(3) symmetry of the Lagrangian with an almost SU(2) \ifmmode\times\else\texttimes\fi{} SU(2) -invariant vacuum (Brandt-Preparata model). We calculate the symmetry-breaking parameters of the Lagrangian and vacuum and predict the mass and decay constant of the $\ensuremath{\kappa}$ meson. Furthermore, from the width of the decay ${\ensuremath{\pi}}_{N}\ensuremath{\rightarrow}\ensuremath{\eta}\ensuremath{\pi}$, we obtain the decay widths of all the scalar mesons. Finally, we investigate the nonelectromagnetic SU(2) breaking and find that it gives a major contribution to the kaon mass difference but only a 5% correction to the pion mass difference. The fact that the scalar mesons are needed to get ${f}_{K}\ensuremath{
e}{f}_{\ensuremath{\pi}}$ and different wave-function renormalization constants for the fields, which enables us to have solutions other than that of Gell-Mann, Oakes, and Renner, demonstrates the importance of the scalar mesons in SU(3)-symmetry-breaking effects.
TL;DR: Li and Pagels as discussed by the authors showed that one can understand the pseudoscalar mesons coming off the chiral limit in an octet-broken fashion, and attributed the major part of the error in the Gell-Mann-Okubo relation to the next leading contributions to the masses, which are O(λ 2ln λ) where λ is the breaking parameter.
TL;DR: In this paper, it is shown that requiring alternative off-mass-shell definitions of the one soft pseudoscalar particle to one-soft-pseudoscalar-particle matrix elements of the scalar densities to coincide, requires the off-Mass-shell definition of soft pseudo-calars to coincide.
Abstract: Here us(x) belongs to a honer of scalar densities, which along with a pseudoscalar nonet vi(x) comprise a (3, 3*)~-(3", 3) representation of ohiral SU3• SU 3 (in this model (~), the symmetry-breaking hadron Hamiltonian density is souo(x)~-SsUs(x)); l~x and M• are the leptonic decay constant and mass of the kappa-meson. By use of PCAC smoothness assumptions and solft-meson techniques, ref. (~) tries to show that requiring alternative off-mass-shell definitions of the one soft pseudoscalar particle to one-soft-pseudoscalar-particle matrix elements of the scalar densities to coincide,
TL;DR: In this paper, a group-theoretic approach was used to derive a precise hybrid formula relating electromagnetic mass differences of pseudoscalar mesons and baryons, which was extended here to the barycn decuplet and the vector-and tensor-meson nonets.
Abstract: A group-theoretic approach, previously used to derive a precise hybrid formula relating electromagnetic mass differences of pseudoscalar mesons and baryons, is extended here to the barycn decuplet and the vector- and tensor-meson nonets. We derive three sum rules relating mass differences within isotopic-spin multiplets of the decuplet, as well as a hybrid formula relating baryon-octet and -decuplet electromagnetic mass differences. Using the present experimental average for the Ξ*−−Ξ*0 mass difference, the hybrid formula can be used to predict MY−−MY+=3.2±0.5 MeV, MΔ0−MΔ+=−0.24±0.16 MeV, and MΔ++−MΔ−=0.72±0.48 MeV. No assumptions concerning U-spin symmetry are required in obtaining these results. With the 27-dimensional part of the SU(2)-breaking interaction taken to be a U-spin singlet, two additional predictions follow: MY−−MY0=3.4±0.6 MeV and MΔ++−MΔ+=3.9±0.9 MeV. Hybrid mass formulas are also derived for meson nonets. Using the present experimental average for the K*0−K*+ mass difference, we predict the neutral ρ meson to be heavier than its charged counterparts by approximately 5 ± 2 MeV.
TL;DR: In this article, a model consisting of eight physical pseudoscalar fields and characterized by a hidden SU(3) symmetry is presented, which is applied to K₁₃ decay and relations among the k-form factors are obtained.
Abstract: A model consisting of eight physical pseudoscalar fields and characterized by a hidden SU(3) symmetry is presented. The model is applied to K₁₃ decay and relations among the K₁₃ form factors are obtained. (LBS)
TL;DR: In this article, a connection between the model that gives the best predictions and a more fundamental field theory for the quarks is also considered and discussed within the framework of the SU3 symmetry.
Abstract: The bosonic spectrum and the Regge trajectories related with two specific nonrelativistic models (volume and surface models) for the quark-antiquark system are computed in detail A connection between the model that gives the best predictions and a more fundamental field theory for the quarks is also considered and discussed Within the framework of theSU3 symmetry the scalar or pseudoscalar field theories are favoured by our analysis in comparison with the vector one
TL;DR: In this article, the conservation of hypercharge and isotopic spin is used in the approximation of a world whose only stable hadrons are the octets of baryons, antibaryons and pseudoscalar mesons.
Abstract: The conservation of hypercharge and isotopic spin is used in the approximation of a world whose only stable hadrons are the octets of baryons, antibaryons and pseudoscalar mesons to obtain upper and lower bounds on the average multiplicities of all nonisosinglet neutral stable hadrons in pp, K+p and π+p collisions The validity of the approximation is discussed
TL;DR: In this paper, the effective bare current-quark masses with asymptotic meson-nucleon and lepton nucleon scattering are derived by making use of the extended light-cone algebra which includes commutators of pseudoscalar densities.
TL;DR: In this article, the Wick-rotated spinor-spinor Bethe-Salpeter equation is applied to study the short distance behavior at vanishing c.m. energies and external masses.
TL;DR: In this article, the quark model was applied to weak production of pseudoscalar mesons, and the absence of some reactions by requiring only nonexotict-channel exchanges was predicted.
Abstract: Applying the quark model to weak production of pseudoscalar mesons, we predict the absence of some reactions by requiring only nonexotict-channel exchanges. Further, we derive relationships between several production cross-sections based on the additivity assumption of the quark model.
TL;DR: In this paper, a sum rule for the spin zero spectral functions of the pseudoscalar axial vector current octet is derived, and the mass of the 9 pseudoscalescalar meson mη1 = 950 MeV.
Abstract: Using GELL-MANN's ansatz for the SU(3)⊗SU(3) symmetry breaking part HSB = -u0 -cu8 in the strong HAMILTONIAN density, where the operators uj (j = 0, 1,…8) are the scalar part of a basis for the {(3,3★) ⊕ (3★,3)} representation of chiral SU(3)⊗SU(3) and where the constant c is a measure for SU(3) breaking within the SU(3)⊗SU(3) breaking, a sum rule for the spin zero spectral functions of the pseudoscalar axial vector current octet is derived. Saturating the sum rule with the lowest lying states, the mass of the ninth pseudoscalar meson can be estimated as mη1 = 950 MeV.