Field-current Identity Research Articles

Meson Form Factors and the Veneziano Model

The ${K}_{l4}$, ${K}_{l3}$, and ${K}_{l2}$ form factors, as well as the pion electromagnetic form factor, are derived from the matrix element $〈\ensuremath{\pi}|{A}_{\ensuremath{\mu}}|\ensuremath{\pi}K〉$ by using partial conservation of axial-vector current, current algebra, and the field-current identity, in addition to the Veneziano representation for the scattering amplitudes. This model contains essentially only one free parameter, by which all the quantities are expressed. The results agree with the present experimental data excellently.

A Model of Parity-Violating Nonleptonic Decays

On the basis of the field-current identity and the universal current-current interaction a divergence-free model of parity-violating nonleptonic decays is constructed. Octet enhancement is a natural consequence of this model and the decay amplitudes are evaluated without introducing any arbitrary parameter. The theoretical results show an excellent agreement with the corresponding experimental ones. These results render a support for the current-current picture of nonleptonic decays.

Field-Current Identity, Chiral Dynamics, and theKl3Form Factors

Field-Current Identity, Chiral Dynamics, and the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>K</mml:mi></mml:mrow><mml:mrow><mml:mi>l</mml:mi><mml:mn>3</mml:mn><mml:mn /></mml:mrow></mml:msub></mml:mrow></mml:math>Form Factors

K l3 form factors of the Veneziano-type

A model for K l3 as well as pion and kaon electric form factors is constructed in terms of the Veneziano-type scattering amplitudes combined with the field-current identity, PCAC and current algebra. No parameters remain to be determined from experiments.

Veneziano-Type Formula for Pion Electromagnetic Form Factor

An expression for the electromagnetic form factor of the pion is derived by using the Veneziano amplitudes for ππ→ππ and ππ→πA1 together with the field-current identity and current algebra. This model predicts √≪rπ2> = 0.83 fm. It is also shown that A1 decays into ρ and π mainly in the S wave.

Asymptotic Symmetry, Lagrangian Gauge Model, and thePVVVertex

We study a model in which $\mathrm{SU}(3)$ breaking in the $\mathrm{PVV}$ vertex is determined by the requirement of asymptotic nonet symmetry. A vector-meson gauge model is constructed which satisfies this asymptotic symmetry condition. The model also incorporates the usual asymptotic symmetry result for the $\mathrm{VPP}$ vertex, the field-current identities, and the algebra of fields. Nevertheless, we obtain a second Weinberg sum rule of the Das-Mathur-Okubo form, and consequently, a quadratic mass formula as in a mass-mixing model. The predictions of the model are compared with available experimental data on meson decays involving the $\mathrm{PVV}$ vertex. The predicted rates for radiative decays of vector mesons are also given.

Field-current identities in a gauge-invariant formulation of massive vector fields

Field-current identities in a gauge-invariant formulation of massive vector fields

Field-Current Identity, Partially Conserved Currents, and the Veneziano Model

Hard-meson partial conservation of axial-vector current and partial conservation of vector current are imposed upon the Veneziano amplitudes. It is seen that these determine inelastic amplitudes (e.g., $\ensuremath{\pi}\ensuremath{\pi}\ensuremath{\rightarrow}\ensuremath{\pi}{A}_{1}$, etc.) in terms of corresponding elastic amplitudes (e.g., $\ensuremath{\pi}\ensuremath{\pi}\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\pi}$). Mass formulas for the $\ensuremath{\kappa}$ and $\ensuremath{\delta}$ meson, equality of many trajectory slopes of either normality, and $\ensuremath{\pi}K$ scattering lengths are obtained, in good agreement with experiment.

The parity - violating internucleon potential and the field - current identity

The parity-violating internucleon potential arising from ϱ, ω and ø exchange is shown to be negligible using the field-current identity (vector-meson dominance). The implications of this result are discussed. In particular, it is pointed out that from an experimental point of view the process n + d → 3He + γ should be more interesting than the process n + p → d + γ.

Field-Current Identities, Broken Symmetries, Current-Mixing Model, and the Algebra of Gauge Fields

It is shown in general that the algebra of the massive gauge fields can recover the current-algebra relations only for the current-mixing model, and how the possible modifications of the spectral-function sum rules can be made within the framework of the gauge-field theory. It is also shown that the Oakes-Sakurai generalization of the first sum rule is a natural consequence of the current-mixing model.

Field-current identity and vacuum polarization effects of hadrons

Vacuum polarization effects of hadrons are calculated in the vector dominance approximation and an application is made in evaluating π 0 - ω interference in the process e + + e - → π + + π -.

Field Current Identity and the Anomalous Magnetic Moment of the Muon

Field Current Identity and the Anomalous Magnetic Moment of the Muon

Field-Current Identities and Nucleon Radii

This paper presents the results of a calculation of the electromagnetic radii of nucleons predicated on the assumption of vector dominance for the hadronic electromagnetic current. Vector dominance is implemented through the use of field-current identities. A new feature of this work is an attempt, for the isovector radii, to take account of the structure of the $\ensuremath{\rho}$-nucleon vertex. While the numerical results are somewhat model-dependent, they do lend support to the view that the radii are determined by the low-energy dynamics of the meson-nucleon system.

Field-current identity, universality and K ℓ3 decay

The dependence of the form factor on the momentum transfer squared is studied in three cases. (i) The universality relation F ππ ϱ (0) = F NN ϱ (0) is generalized to small q 2 by means of field-current identity and a ‘universality’ model. (ii) The q 2-dependence of the weak form factor of the pion (kaon) ƒ π(q 2) (ƒ K (q 2)) is found to be related to that of the pion (kaon) charge form factor. (iii) The K ℓ3 decay parameters λ +, λ −, ξ(0) are calculated in two models. They are compatible with present experimental data. Special attention is paid to the hard-pion (-kaon) and soft-pion (-kaon).

Gauge Invariance, Broken Symmetries, and Field-Current Identities

Gauge Invariance, Broken Symmetries, and Field-Current Identities

Field-Current Identities and Intermediate Bosons

The observed total weak-interaction current ${{\mathcal{I}}_{\ensuremath{\mu}}}^{\mathrm{wk}}(x)$ and the observed total electromagnetic current ${{\mathcal{I}}_{\ensuremath{\mu}}}^{\ensuremath{\gamma}}(x)$ are assumed to be, respectively, the same local operators, apart from constant multiplicative factors, as the hypothetical charged intermediate boson field ${W}_{\ensuremath{\mu}}(x)$ and the corresponding neutral intermediate boson field ${{W}_{\ensuremath{\mu}}}^{0}(x)$. The field algebra satisfied by these current operators is discussed. It is shown that, neglecting higher-order weak-interaction effects, one can obtain finite higher-order electromagnetic corrections for the known hadrons and leptons, such as the electromagnetic mass shifts of $p$, $\ensuremath{\pi}$, $e$, $\ensuremath{\mu}$, etc., and the radiative corrections to the weak decays of these particles.

Chiral Dynamics, Field-Current Identity, and theKl3form Factors

Based on the notions of chiral dynamics and the field-current identity as applied to the broken SU(3), theoretical expressions for the form factors ${f}_{\ifmmode\pm\else\textpm\fi{}}(t)$ are obtained. A small $\ensuremath{\xi}$ ($|\ensuremath{\xi}|\ensuremath{\ll}1$) and a large $|{\ensuremath{\lambda}}_{\ensuremath{-}}|$ (an order of magnitude larger than ${\ensuremath{\lambda}}_{+}$) are predicted. [However, the product $\ensuremath{\xi}{\ensuremath{\lambda}}_{\ensuremath{-}}$ is expected to be small.]

Field-Current Identities and Algebra of Fields

Field-Current Identities and Algebra of Fields