M. Jain

Elastic and inelastic scattering of protons from 6Li between 25 and 45 MeV

Abstract The elastic and inelastic scattering of protons from 6Li has been studied at incident energies of 25.9, 29.9, 35.0, 40.1 and 45.4 MeV. The 2.18 MeV (3+, T = 0) first excited state of 6Li was found to be strongly excited, but the 3.56 MeV (0+, T = 1) second excited state was quite weakly excited. Angular distributions for excitation of the 2.18 MeV level were measured at all five energies, while angular distributions for excitation of the 3.56 MeV level were extracted only at 25.9 and 45.4 MeV. To test the applicability of the optical model for the scattering of protons from such a light nucleus the elastic scattering angular distributions have been analyzed using the eleven-parameter search code SEEK. Available polarization angular distributions were included in the analysis. Reasonable fits to the data have been obtained with an average geometry potential. Theoretical estimates of the real part of the optical potential and the inelastic scattering differential cross sections have been made using the microscopic model for proton-nucleus scattering. Both phenomenological and realistic forces have been considered and the necessary nuclear transition densities have been extracted from experimental elastic and inelastic electron scattering data. An estimate of a possible spin-spin term in the optical potential has also been made.

A study of the 40Ca(p, 2p) 39K reaction at 45.0 MeV☆

Abstract Angular correlations for the reaction 40 Ca(p, 2p) 39 K have been measured at symmetric, coplanar angles between 30° and 105° for both the ground state and first excited state of 39 K. The angular correlations are compared with a distorted-wave t -matrix calculation using a non-local bound-state wave function.

Many-nucleon transfer reactions of protons with 12C and 13C at 45.0 MeV

Abstract Differential cross sections for the 12 C(p, 6 Li) 7 Be, 13 C(p, 6 Li) 8 Be, 13 C(p, 6 Li) 8 Be∗ (2.90 MeV), and 13 C(p, 7 Li)7Be reactions have been measured at an incident proton energy of 45.0 MeV. The measurements extend for the most part over laboratory angles from 15° to 80°. The cross sections for all the reactions are found to be very small and are of the order of 10 μb. Nevertheless, for 13 C the six-nucleon transfer reaction has a cross section about 5 times that of the five-nucleon transfer reaction. The angular distributions have been analysed using a distorted-wave Born approximation (DWBA) theory assuming the presence of lithium clusters in the target nuclei.

Comments on the existence of broad resonances in 3He

Abstract Recently, experimental evidence has been presented for the existence of broad T = 1 2 resonances in the three-nucleon systems. As a continuation of earlier studies, the 6 Li(p, τ) and 6 Li(p, α) reactions were investigated using 45.0 MeV incident protons. τ- and α-particle spectra were measured at extreme forward angles using a ΔE - E - rmVETO detector telescope in conjunction with an analog particle identifier. Excitation energies up to 30 MeV in 3 He could be examined. The spectra do not show any structure that can be related to the resonances observed previously. However, the spectra exhibit evidence for quasi-free scattering of protons from the α-cluster in 6 Li.

Kinematics and phase space for two-particle correlations in three-, four-, and five-particle final-state reactions☆

Abstract Kinematics and phase space are discussed for multiple-particle final-state reactions with up to five particles in the final state. It is assumed that the rest masses of all particles are known and that complete kinematic information is obtained for two of the outgoing particles. The effects of possible resonances for some particular situations are considered.

A STUDY OF THE 3He(p,2p)d AND 3He(p,2p)pn REACTIONS AT 45.0 MeV*

Publisher Summary This chapter presents the study of 3He(p,2p)d and 3He(p,2p)pn reactions at 45.0 MeV. Quasi-free scattering experiments can provide information about the wave function of the struck particle in the nucleus. The data has been analyzed using the plane and distorted wave impulse approximations and valuable nuclear structure information has been obtained. At high incident energies, the reaction is fairly well understood as there is direct interaction of the incident particle with one nucleon or a cluster in the nucleus. At energies around 50 MeV, the increased complexity of the reaction mechanism and the difficulty in treating the off-shell effects make the interpretation of the data difficult. Theoretical momentum distributions for an S-state relative motion wave function are calculated from the overlap of Irving–Gunn and Hulthen wave functions. Consistent treatment of the off-shell cross sections and multiple scattering effects is required to reliably extract nuclear structure information for 3He.