International Journal of Modern Physics E

The separation energy and half-life of some heavy proton emitting nuclei, and the single-particle structure of unbound ¹¹N, have been evaluated by implementing a careful numerical treatment to solve the Schrödinger equation in a continuum discretization context. The basic scheme behind the method consists in using the ground-state proton emitter in connection with an isolated single-particle resonance.

Total reaction cross sections for 50 and 100 MeV protons have been calculated for several nuclei using Gambhir–Patil semi-phenomenological nucleon density in the Coulomb modified Glauber model. It is shown that the semi-phenomenological nucleon density distribution provides quite satisfactory description of the observed A-dependence of the proton reaction cross sections.

The exact solutions of the (2+1)-dimensional Dirac equation with a Coulomb potential and a scalar one are analytically presented by studying the second-order differential equations obtained from a pair of coupled first-order ones. The eigenvalues are studied in some detail.

We study, theoretically, the fusion of the light proton-rich exotic nuclei ¹⁷F and ⁸B at near-barrier energies in order to investigate the possible role of breakup processes on their fusion cross sections. To this end, coupled channel calculations are performed, considering the couplings to the breakup channels of these projectiles. In case of ¹⁷F, the coupling arising out of the inelastic excitation from the ground state to the bound excited state and its couplings to the continuum have also been taken into consideration. It is found that the inelastic excitation/breakup of ¹⁷F affect the fusion cross sections very nominally even for a heavy target like Pb. On the other hand, calculations for fusion of the one-proton halo nucleus ⁸B on a Pb target show a significant suppression of the complete fusion cross section above the Coulomb barrier. This is due to the larger breakup probability of ⁸B as compared to that of ¹⁷F. However, even for ⁸B, there is little change in the complete fusion cross sections as compared to the no-coupling case at sub-barrier energies.

The physics search potential of the recently proposed FEL ⊗ LHC collider is illustrated in the sample of the collective excitations of the ¹⁵⁴Sm nucleus. In this facility the accelerated fully ionized nuclei will "see" the keV energy FEL photons as a MeV energy laser beam. The main advantages compared to the traditional methods are the tunability, monochromaticity and high polarization of the FEL beam. The advantages result in higher statistics and the possibility to investigate individual levels.

In recent papers,^1,2 it has been shown that the presence of negative norm states or negative frequency solutions are indispensable for a fully covariant quantization of the minimally coupled scalar field in de Sitter space. Their presence, while leaving unchanged the physical content of the theory, offers the advantage of eliminating any ultraviolet divergence in the vacuum energy² and infrared divergence in the two point function.³ We attempt here to extend this method to the interacting quantum field in Minkowski space-time. As an illustration of the procedure, we consider the λϕ⁴ theory in Minkowski space-time. The mathematical consequences of this method is the disappearance of the ultraviolet divergence to the one-loop approximation. This means, the effect of these auxiliary negative norm states is to allow an automatic renormalization of the theory in this approximation.

A phenomenological method of analysis for heavy-ion elastic scattering data at intermediate energies is proposed within the framework of the optical limit approximation of the Glauber multiple scattering theory. The essential point of our method is to evaluate the NN scattering amplitude in terms of a phenomenological effective NN potential the parameters of which are varied to fit the experimental data. It is applied to analyze ¹²C–¹²C elastic scattering data in the energy range of 25–200 MeV/nucleon with a good degree of success.

The collective bands of the N = Z nucleus ⁶⁸Se are studied within our deformed configuration mixing shell model based on Hartree–Fock states. The configuration space consists of the spherical single particle orbits 1p_3/2, 0f_5/2, 1p_1/2 and 0g_9/2 with ⁵⁶Ni as the inert core. A modified Kuo interaction for this basis space has been used in our calculation. The calculated ground band, K = 2⁺ excited band and the K = 5^- excited band agree reasonably well with the experiment. Our calculation shows that the ground band is essentially of oblate shape and the excited K = 2⁺ band is of prolate shape. This is in agreement with the conclusions drawn from the recent experimental analysis.

In this paper we explore the effects of the meta-stable states of dtμ* molecules on crucial parameters in μCF such as total sticking coefficient and muon cycling rate. For this purpose we establish a new approach in the study of the determination of the q_1s parameter and the relative population of muonic atoms by solving the kinetics of μCF. We have answered the basic questions about the muon total sticking including the side-path effects.

A new classification of the fundamental particles based upon the use of only three additive quantum numbers (charge, particle number, generation quantum number) compared with the nine additive quantum numbers of the Standard Model (charge, lepton number, muon lepton number, tau lepton number, baryon number, strangeness, charm, bottomness, topness) is presented. This classification provides a new basis for the weak isospin symmetry characteristic of both leptons and quarks.

Absolute total cross sections for single-electron-capture are measured for and N⁺ ions traversing N₂ molecular gas of collision energies in the range of 0.60 to 1.5 keV. These cross sections are found to be in the range of 3.97 - 6.25 Ų for ions, and in the range of 0.46 - 1.67 Ų for N⁺ ions. A comparison is made between the present measurements of the total cross sections of the N⁺ + N₂ system and all the experimental results, which are represented by B. G. Lindsay et al.,¹ for the O⁺ + N₂ system. The present measurements of the total cross section of the N⁺ + N₂ system are in partial agreement with measurements of B. G. Lindsay et al.,¹ and in an excellent agreement with the measurements of Moran et al.,² The present measurements of the total cross sections of the system are compared to the theoretical calculations and the experimental results of the same system.²³ The results are in disagreement with each other.

We calculate the beta decay rate of the free neutron including effects due to (i) a neutrino mass around 1 eV, (ii) deviations from the leptonic V-A structure, (iii) nucleon form factors , G_A(q²), and (iv) W^- propagation. At the end-point energies linear neutrino mass effects in are almost exclusively kinematical. If the neutrino spectrum is (almost) degenerate, neutrino oscillations cannot uniquely determine the mass of the neutrino, and direct mass determinations become necessary. The traditional Kurie plot and a partially integrated decay rate are found to be sensitive to a neutrino mass between 1 eV and 3 eV.