Interactions of magnetic monopoles with nuclei and atoms: Formation of bound states and phenomenological consequences

We discuss the binding of magnetic monopoles to nuclear and atomic systems. The energy spectrum is calculated, by assuming an interaction with a hard core. The formation process of monopole-nucleus bound states is analysed and it is shown that monopoles reaching Earth are most likely bound to a proton. We also discuss phenomenological implications of the existence of bound states in connection with the monopole catalysis of proton decay.     

The deuteron and its magnetic moment the effects of non-local nuclear forces and of unitary transformations

The deuteron theory is renewed and completed for non-local Hamiltonians. A method to calculate deuteron wave functions is given. The formula for the current density and the magnetic dipole moment of a non-local potential is derived, and applied to the GCT, GT, and HJ-potential. The effects of a unitary transformation on the deuteron data — electric quadrupole moment, magnetic dipole moment, and radius — are shown. For the numerical calculations the Ristig-Kistler transformation and the HJ-potential were used. It is shown that an overall fit cannot be reached.     

Influence of pairing on the nuclear matrix elements of the neutrinoless betabeta decays

We study in this Letter the neutrinoless double beta decay nuclear matrix elements (NME's) in the framework of the interacting shell model. We analyze them in terms of the total angular momentum of the decaying neutron pair and as a function of the seniority truncations in the nuclear wave functions. This point of view turns out to be very adequate to gauge the accuracy of the NME's predicted by different nuclear models. In addition, it gives back the protagonist role in this process to the pairing interaction, the one which is responsible for the very existence of double beta decay emitters. We show that low seniority approximations, comparable to those implicit in the quasiparticle RPA in a spherical basis, tend to overestimate the NME's in several decays.     

High-energy phenomena,short-range nuclear structure and QCD

A systematic review and theoretical analysis of the experimental data on multi GeV lepton, photon, hadron, deuteron (nucleus) reactions from nuclei forbidden in the case of scattering from free nucleons is presented. It is shown that all these data can be quantitatively described as a manifestation of short-range few nucleon correlations. Calculations for elastic and (deep)inelastic electromagnetic and weak form factors of the deuteron and other nuclei, are given. The inclusive production of leading particles in the nucleus fragmentation region in high-energy lepton, hadron or nucleus-induced collisions is analyzed. The straightforward correspondence between the Weinberg equation for the light-cone wave functions of the deuteron and the non-relativistic Schrödinger equation is found. It is shown that the predictions of quantum chromodynamics for short-distance phenomena in nuclei are in agreement both with experimental data and theoretical expectations due to short range correlations in nuclei. Several feasible experiments are considered which could establish the existence of relativistic nuclear physics.     

Charge-monopole molecule and vanishing of the Schwinger string

As is well known [1, 2], the wave functions of charge scattering states in the magnetic monopole field are expanded in the eigenfunctions of symmetric quantum top rotation. The established direct relationship of the total momentum operators of these systems causes the Schwinger string to vanish and demonstrates that the charge and monopole system has the property of a diatomic molecule.     

Three-body model for stripping nuclear reactions

A three-body model for the deuteron stripping nuclear reactions is presented. A set of three integral equations is obtained for the wave functions of the three-body problem by introducing a decomposition into angular momentum states into the Lippmann-Schwinger equation. Simple two-particle interactions with separable potentials are used. These separable potentials reduce the three-body problem to the solution of coupled sets of one-dimensional Fredholm integral equations. The angular distributions for²⁸Si(d,p)²⁹Si and⁴⁰Ca(d, p)⁴¹Ca stripping reactions are calculated. From the extracted spectroscopic factors, good agreement with the experimental measurements is obtained.     

Localized oscillator expansions of nuclear two-body wave functions

Harmonic oscillator expansions are applied to two-body systems simulating the deuteron, triton and alpha particle. Convergence rates in energies and wave functions can be significantly improved when the expansions are localized by first subtracting an approximate asymptotic wave function.     

Investigation of the nuclear quadrupole interaction in ZnO by the method of perturbed angular correlations of nuclear radiations

It has been demonstrated that the sign and magnitude of the nuclear quadrupole interaction in ZnO can be determined using perturbed angular correlations of nuclear radiations. Information on the magnitude of the nuclear quadrupole interaction for the 184-keV ⁶⁷Zn level can be obtained from the observation of the gamma-gamma perturbed correlation of the directions for the ⁶⁷Ga → ⁶⁷Zn decay, and information on the magnitude and sign of the nuclear quadrupole interaction can be derived from the experiment on the induced beta-gamma correlation of the directions for the ⁶⁷Cu $ \xrightarrow{{\beta ^ - }} $ \xrightarrow{{\beta ^ - }} ⁶⁷Zn decay. The results of measurements have been interpreted using the calculation of the electric field gradient in the ZnO crystal by the full-potential linearized augmented plane wave method with the generalized gradient approximation of the exchange-correlation potential.     

Scattering of fermions on the SU(5) colorless magnetic monopole

We discuss the scattering of fermions (d?, u-quarks and e^c) on the SU(5) colorless magnetic monopole. The radial functions of scattering wave are totally separated from the angular parts in the Dirac equations which then reduce to a set of coupled ordinary differential equations. We solve these equations numerically for the d?e^c group with j = 1, and get the result that only the incoming wave of d with j = 1 and j′ = 0 can be scattered into e^c. The cross section is obtained which is intimately connected with the catalysis effect of the monopole for baryon decay.     

The finite depth of the nuclear potential well in the exciton model of preequilibrium decay

The density of states and the transition rates are derived for the equidistant spacing model with the limitation on the hole maximum energy. The previous results of Blann are generalized. The influence of the finite depth of nuclear potential well on the pre-equilibrium decay within the exciton model is investigated. The calculations of proton and deuteron spectra from the reaction¹²⁰Sn+p are presented.     

Problems of angular momentum projection in nuclear physics

In nuclear models approximate wave functions are often used which do no have sharp angular momentum as required of the exact wave functions. It seem obvious that model wave functions of this type should be improved by projection onto states of good angular momentum. It is not the purpose of this paper to discuss the technical difficulties of projection (which can be formidable for many particle systems), but rather to present in an elementary way certain fundamental ambiguities in the use of projection. An application to high spin states near the yrast line is suggested.     

Meson exchange and isobar admixture contributions to elastic electron-deuteron scattering

The deuteron structure functions for elastic electron scattering and the deuteron static properties have been calculated with the inclusion of isobar admixtures to the deuteron wave function and meson exchange currents. At higher momentum transfers the structure functions are increased significantly because of the strong enhancement of the deuteron magnetic dipole form factor. Roughly 15–35% of this enhancement depending on the momentum transfer arise from the meson exchange currents.     

Nucleon polarization and the nuclear charge operator

Effects of nucleon polarization on the nuclear charge operator have been evaluated in a constituent quark model. At momentum transfer q ≈ 4 fm^?1 monopole, dipole and quadrupole excitations are of equal importance. In a harmonic oscillator model for ³He all multipolarities give negative contributions, leading to an overall contribution comparable to the relativistic pair effect. The influence of realistic wave functions, coupling constants and off-shell form factors is discussed.     

Deuteron electromagnetic form factors with the light-front approach

The electromagnetic form factors and low-energy observables of the deuteron are studied with the help of the light-front approach, where the deuteron is regarded as a weakly bound state of a proton and a neutron. Both the S and D wave interacting vertexes among the deuteron, proton, and neutron are taken into account. Moreover,the regularization functions are also introduced. In our calculations, the vertex and the regularization functions are employed to simulate the momentum distribution inside the deuteron. Our numerical results show that the lightfront approach can roughly reproduce the deuteron electromagnetic form factors, like charge G_0, magnetic G_1, and quadrupole G_2, in the low Q~2 region. The important effect of the D wave vertex on G_2 is also addressed.     

Note on relativistic coulomb wave functions

Some results on the wave functions of a Dirac particle in a point charge Coulomb field are presented. Angular momentum and parity eigenfunctions are tabulated and used to construct solutions representing asymptotically a plane wave plus incoming or outgoing spherical waves. The solutions forr → 0 are exhibited in a form closely similar to the corresponding free particle spinors and are used to construct generalizations of the Casimir projection operators for positive or negative energy particles. The various wave functions presented are useful in calculations such as nuclear beta decay in which it is necessary to take into account final (or initial) state Coulomb interactions. Because of the similarity of the wave functions to those of a free particle, calculations including rigorously all Coulomb corrections for such processes as allowed beta decay can be performed with little more effort than is involved in a calculation using only plane waves.     

Renormalized proton- neutron QRPA and double beta decay of 82Se to excited states in 82Kr

We apply the self-consistent renormalized proton-neutron QRPA (RQRPA) method to calculate the two-neutrino double beta (2νββ) decay matrix elements associated with the ground-state and excited-state transitions of the ⁸²Se → ⁸²Kr decay. The RQRPA method is an extension of the pnQRPA method and promotes the Pauli exclusion principle violated by the pnQRPA ground state and yields more stable nuclear matrix elements with increasing strength of the proton-neutron interaction. In the present work the RQRPA wave functions are also used to evaluate 2νββ-decay rates to excited final states. The resulting theoretical half lives are compared with the new stringent experimental limits obtained by using a HPGe detector and external sources of enriched selenium.     

Triggering of nuclear isomers by X-ray laser

We studied the decay of nuclear isomeric states in the field of the X-ray laser. The laser pulses are described by the Gaussian wave packet of linearly polarized electromagnetic waves. At first stage the laser short pulse generates nuclear transition in the intermediate excited state, which afterwards decays into the final state with emission of γ quantum. Simple formulas are derived for the induced transition probability, which well correlate with known results, obtained previously for the incoherent X-ray radiation.     

The average monopole polarization charge and its relation to nuclear incompressibility and effective mass

The average monopole polarization charge for occupied states is related to the nuclear incompressibility and effective mass. This is done with a previously used approximation of a Taylor Expansion in the Hartree-Fock theory employing Skyrme interactions.     

Relativistic description of polarized-deuteron fragmentation accompanied by the emission of high-transverse-momentum protons

Available experimental data on the tensor analyzing power for nuclear relativistic-deuteron fragmentation accompanied by the emission of high-transverse-momentum protons are analyzed within light-front quantum mechanics. It is shown that, in contrast to calculations with standard wave functions, calculations employing the relativistic deuteron wave function obtained by V. A. Karmanov and his coauthors on the basis of light-front dynamics can explain the entire body of data without resort to additional degrees of freedom.