Poincare Invariant Quantum Mechanics Research Articles

Radiative decays of light vector mesons in Poincare invariant quantum mechanics

This work dedicated to describing two-body compounded system of quarks (meson) in point form of Poincare invariant quantum mechanics with potential, which was offered by so-called Mock-meson model. Authors shows process of calculation the basis parameters of the model by the variational method and followed applications for radiative decay processes. For such calculation authors use the simplest radiative decay scheme. Comparing results with experimental data was shown how to calculate the anomalous part of quark magnetic moment.

Описание радиационных распадов $V\to P\gamma^{*}$ в различных формах Пуанкаре-инвариантной квантовой механики

Работа посвящена описанию радиационных распадов $V \to P \gamma^{*}$ в различных основных формах Пуанкаре-инвариантной квантовой механики (ПИКМ). Для построения матричного элемента электромагнитного тока перехода используется специальная процедура, удовлетворяющая условиям лоренц-ковариантности и сохранения. В качестве иллюстрации развитого формализма в модифицированном релятивистском импульсном приближении проведено описание радиационного перехода $\rho \to \pi \gamma^{*}$. Получено аналитическое выражение для переходного формфактора $F_{\pi \rho}(Q^2)$, совпадающее во всех формах ПИКМ. Выполнены численные расчеты переходного формфактора с двумя типами модельных волновых функций.

Electromagnetic and Axial Form Factors of Octet and Decuplet Baryons

We report from a study of the elastic electromagnetic and axial form factors of all lowest baryon states with flavors up, down, and strange along relativistic constituent-quark models. We consider the baryons as relativistic bound states of three constituent quarks and solve the eigenvalue problem of the invariant mass operator. The corresponding eigenstates are employed to calculate manifestly covariant form factors within the point form of Poincare-invariant quantum mechanics. The electromagnetic and axial current operators are constructed along the spectator model in point-form relativistic dynamics. We have thus obtained covariant predictions for the electroweak form factors, for momentum transfers up to Q2 ~ 4 GeV2, as well as the electric radii, magnetic moments, and axial charges. The theoretical results in general agree very well with existing phenomenological data. In cases, where no experimental information is yet available, the results are well compatible with data from lattice quantum chromodynamics.

Построение оператора электромагнитного тока в разных формах Пуанкаре-инвариантной квантовой механики

In an approach of the Poincare-invariant quantum mechanics in a modified relativistic impulse approximation performed construction of the operator of the electromagnetic current for different forms of dynamics (instant form, point form and dynamics of the light-front). The current operator is constructed according to the conditions of Lorentz covariance and conservation. It is shown that the analytical expressions for the form factor are identical in all forms of dynamics. Numerical calculations of the pion form factor with the wave function obtained by the variational method are in good agreement with experiment.

ON ANAPOLE FORMFACTOR OF THE PROTON

In this paper we discuss the possibility of existence of anapole formfactor of the proton. In the framework of hypothesis of violation of discrete symmetries in electromagnetic processes involving composite systems with strong interactions we discuss the results of modern experiments on elastic ep-scattering and recent results on the measurement of radius of proton. In the approach of Poincare invariant quantum mechanics the analysis of experiments on elastic ep-scattering is made and electromagnetic and anapole formfactors of proton are calculated

ELECTROMAGNETIC FORM FACTORS OF PSEUDOSCALAR MESONS

Mean-square radii and electromagnetic form factors of light mesons are obtained in the framework of Poincare covariant quark model, which is basedon the point form of Poincare invariant quantum mechanics. Calculations areperformed with the use of the requirement of self-consistent description of electroweak properties and masses of pseudoscalar and vector mesons.

Poincaré Invariant Three-Body Scattering at Intermediate Energies

Relativistic Faddeev equations for three-body scattering are solved at arbitrary energies in terms of momentum vectors without employing a partial wave decomposition. Relativistic invariance is incorporated within the framework of Poincare invariant quantum mechanics. Based on a Malfliet-Tjon interaction, observables for elastic and breakup scattering are calculated and compared to non-relativistic ones. The convergence of the Faddeev multiple scattering series is investigated at higher energies.

Relativistic description of strong baryon-resonance decays

We report some recent developments in the theoretical description of strong baryon-resonance decays within relativistic constituent-quark models. In particular, we address covariant predictions for partial decay widths obtained with a spectator-model decay operator in the framework of Poincare-invariant quantum mechanics. The main characteristics of the results for the π, η, and K decay widths are summarized and their consequences for the SU(3) flavor-multiplet classification of baryon resonances are indicated. It turns out that for a consistent picture to emerge some low-lying two-star resonances need to be included into the baryon classification scheme.