Scattering Of Composite Particles Research Articles

Scattering of composite particles in a gauge theory with confinement

Firstly, we discuss a new method based on the Hamiltonian formulation and on the Monte Carlo projector technique in order to compute the Minkowski time evolution and S-matrix. We present results for NN scattering in a non-relativistic potential model. Secondly, we present numerical results of a lattice calculation on scattering of two composite particles in QED 1+1, which confines single fermions. The composite particles are taken as neutral, fermion-antifermion, lowest mass eigen states of the Hamiltonian. We use the light-cone momentum representation on a lattice and compute the time evolution and S-matrix by diagonalizing the lattice Hamiltonian.

Scattering of composite particles in a gauge theory with confinement.

In order to model positronium-positronium scattering in QED or meson-meson scattering in QCD, we consider ${\mathrm{QED}}_{1+1}$, which is a gauge theory and confines single fermions. We present first numerical results of a lattice calculation on scattering of two composite particles. The composite particles are taken as neutral, fermion-antifermion, lowest-mass eigenstates of the Hamiltonian. We use the light-cone momentum representation on a lattice and employ a nonperturbative time-dependent method to compute the S matrix.

Scattering of composite particles in a QCD-like model

As a model of QCD, we study QED 1 + 1, which is a gauge theory does not have asymptotically free single fermions. We use the light-cone momentum representation on a lattice and a non-perturbative time-dependent method to compute the S-matrix. After introducing Coulomb screening of the interaction, free single fermions can exist asymptotically and we compute fermion-antifermion scattering. We also compute two-fermion-two-antifermion scattering and relate it to the amplitude for scattering of two fermion-antifermion bound states. We discuss convergence to the continuum limit and renormalization.

Scattering of composite particles

Scattering of composite particles

Scattering of composite particles and the quasipotential approach in quantum field theory

Scattering of composite particles and the quasipotential approach in quantum field theory

A New Analytical Derivation of Kernels in the Resonating Group Method for Composite-Particle Scattering and Molecule-Like Structures: Derivation from Kernels in the Generator Coordinate Method and Application to 16O +

Exchange kernels in the resonating group method are derived analytically from those in the generator coordinate method without any use of inverse operators of Gauss transforma­ tion. The whole kernels of 160+a system with Coulomb interaction are given, divided into various exchange mechanisms. Derivation in the cases where two interacting nuclei have different oscillator parameters and where other channels are included is also presented. § I. Introduction The cluster structure and molecular aspect in nuclei have been studied ex­ tensively in terms of interaction between composite particles. 1l Recently, many attempts based on phenomenological and microscopic approaches have been made with the progress of experiments on composite-particle scattering and cluster transfer reactions. 2l It must be one of the main aims of such studies to investi­ gate the microscopic mechanism of interaction between composite nuclei by em­ ploying the many-body Hamiltonian and taking into account the Pauli principle exactly. The resonating group method3l (RGM) ·is very powerful to this aim. For instance, on the basis of the RGM a deep understanding was obtained concern­ ing the origin of the repulsive core of phenomenological a-a potential as a model representation of the existence of almost energy-independent behaviour of the nodal point.'l Saito 5l showed that the behaviour is understood as a result of or­ thogonality of the relative wave function to forbidden states and proposed an orthogonality condition model which describes the inner part of interaction be­ tween composite particles with the orthogonality condition and the outer part with a direct potential. This approximated model has obtained successful results for a-a scattering 5l' 6l and for a-decay widths of 160 +a system.7l Although the RGM approach is very powerful in extracting physical understandings from it­ self, its application to a system heavier than a+ a has been generally regarded as very much difficult.

On the Applicability of the Generator Coordinate Method to Composite-Particle Scattering

A phase-shift analysis of alpha - alpha scattering is performed up to 60 MeV (c.m.). Phase shifts with the Coulomb effect calculated by use of the generator coordinate method (GCM) are shown, along vith those found by using the resonating-group method (RGM). The good agreement between the results suggests the possibility that the GCM can be used as a substitute for the RGM in scattering problems over a wide energy region. Agreement with experimental values is fairly good: it is expected that even better agreement can be obtained through use of a more realistic nuclear force with the correct range. (1 figure) (RWR)

On the Extension of the Resonating Group Treatment of Composite Particle Scattering to the Heavy System

A new analytical method of calculating the kernels in the resonating group treatment of the composite particle scattering is presented. It converts the calculations of matrix elements to those in terms of the Slater determinantal wave functions. By this the range of applicability of the resonating group method can be extended to systems heavier than alpha + alpha such as alpha + /sup 16/O and possibly /sup 16/O + /sup 16/O. Since the method treats the lighter particle as a cluster in the valence orbits outside the core of the heavier particle, the correspondence of the resonating group treatment to the continuum shell model is clearly displayed. As an application, kernels in the alpha + /sup 16/O system are calculated and by using them the validity of the orthogonality condition model in this system is investigated which is originally proposed by Saito in the alpha + alpha system. (auth)

Effect of Approximate Wave Functions in Composite-Particle Scattering

Many investigators have studied the scattering of low-energy nucleons by light nuclei using a single-particle effective potential which is derived from a many-nucleon Hamiltonian under the assumption that the contribution to the scattering by virtual excitations of the target nucleus can be neglected. In addition, they have approximated the ground-state wave functions of the target nuclei by crude variational wave functions, thus introducing an unknown error into the results of the scattering calculation. In this paper we investigate that error for the specific case of neutron-triton scattering. To do this we derive three approximate effective potentials which differ from each other and from the exact single-particle effective potential by the same order in the error of the approximate triton wave function. The difference between the phase shifts calculated with the approximate potentials gives an indication of the uncertainty in the calculations, and as the approximate triton wave function is improved the difference decreases. Our work shows that previous calculations involve large errors which may be reduced by improving the approximate target wave function.

An Extension of the Faddeev Formalism to Composite-Particle Scattering

An Extension of the Faddeev Formalism to Composite-Particle Scattering

An Extension of the Faddeev Formalism to Composite-Particle Scattering

An Extension of the Faddeev Formalism to Composite-Particle Scattering