124431237
Massive neutron stars with a hyperonic core: A case study with the IUFSU relativistic effective interaction
The recent discoveries of massive neutron stars, such as PSR J0348 + 0432 and PSR J1614–2230, have raised questions about the existence of exotic matter such as hyperons in the neutron star core. The validity of many established equations of states (EoSs) like GM1 and FSUGold are also questioned. We investigate the existence of hyperonic matter in the central regions of massive neutron stars by using relativistic mean field (RMF) theory with the recently proposed Indiana University Florida State University (IUFSU) model. The IUFSU model is extended by including hyperons to study the neutron star in β equilibrium. The effect of different hyperonic
3205210
Correction to Relativistic Mean Field binding energy and NpNn scheme
Abstract The differences between the experimental and Relativistic Mean Field binding energies have been calculated for a large number of even–even nuclei from A = 50 to 220. Excluding certain mass regions, the differences, after suitable corrections for particular isotope chains, are found to be proportional to the Casten factor P, chosen as a measure of n – p interaction strength in a nucleus. Results for even-Z odd-N nuclei are also seen to follow the same relation, if the odd–even mass difference is taken into account following the semiempirical formula. This indicates that the n – p interaction is the major contributor to the difference between the calculated and the experimental binding energies.
123101749
Formation of Anti-Hydrogen in Presence of Laser Field in Antiproton-Positronium Collisions
A detailed calculation in the framework of first Born approximation has been presented for the study of anti-hydrogen formation in antiproton-positronium collisions in presence of a laser field considered classically in the dipole approximation. The projectile-laser field interaction and the dressing of the bound states are considered to first order. The anti-hydrogen formation amplitudes are obtained in closed forms in the Ap gauge, the field direction being parallel to the incident momentum. The differential as well as total cross-sections are presented for no photon (l = 0) and one photon (l = ±1) exchange with field strengths e0 = 106 V/cm (0.0002 a.u.) and e0 = 107 V/cm (0.002 a.u.) and compared with the corresponding field free results.
11873642
Spectroscopic factors for alpha decay in the N(p)N(n) scheme
Abstract Lifetime values for alpha decay in even–even nuclei with Z = 84 – 98 and N = 128 – 152 have been calculated in the superasymmetric fission model. The interaction between the alpha particle and the daughter nucleus has been formed in the double folding approach using a density dependent NN interaction. The densities have been obtained using the Relativistic Mean Field formalism. The spectroscopic factors for the decays have been deduced and are shown to vary smoothly as a function of effective numbers of valence nucleons, N p and N n chosen with a suitable core. The implication of such a smooth behaviour has been discussed.
16195515
Microscopic calculation of half lives of spherical proton emitters
Abstract Half life values for proton radioactivity in nuclei have been calculated in the WKB approximation. The microscopic proton–nucleus potential has been obtained by folding the densities of daughter nuclei with two microscopic NN interactions, DDM3Y and JLM. The densities have been obtained in the Relativistic Mean Field approach in the spherical approximation using the force FSU Gold. No substantial modification of results has been observed if other common forces are employed. The calculated results for the decays from the ground state or the low-lying excited states in almost all the nuclei agree well with experimental measurements. Reasons for large deviations in a few cases have been discussed. Results in 109 I and 112,113 Cs show that the effect of deformation is small contrary to earlier calculations. Predictions for possible proton radioactivity have been made in two nuclei, 93 Ag and 97 In.
120242594
Weak-interaction strength from charge-exchange reactions versus {beta} decay in the A=40 isoquintet
We report a measurement of the Gamow-Teller (GT) strength distribution for {sup 40}Ar{yields}{sup 40}K using the 0 deg. (p,n) reaction. The measurement extends observed GT strength distribution in the A=40 system up to an excitation energy of {approx}8 MeV. In comparing our results with those from the {beta} decay of the isospin mirror nucleus {sup 40}Ti, we find that, within the excitation energy region probed by the {beta}-decay experiment, we observe a total GT strength that is in fair agreement with the {beta}-decay measurement. However, we find that the relative strength of the two strongest transitions differs by a factor of {approx}1.8 in comparing our results from (p,n) reactions with the {beta} decay of {sup 40}Ti. Using our results we present the neutrino-capture cross section for {sup 40}Ar.
121755167
Electron capture decay of In-116 and nuclear structure of double beta decays
Quasiparticle-random-phase-approximation (QRPA) calculations of double {beta} decays have not been able to reproduce data in the A=100 system. We propose the A=116 system{emdash}because of its smaller deformation{emdash}as a simpler system to test QRPA calculations. We present results of two experiments we performed, which determine the electron-capture-decay branch of {sup 116}In to be (2.27{plus_minus}0.63){times}10{sup {minus}2}{percent}, from which we deduce logft=4.39{sub {minus}0.15}{sup +0.10}. We present QRPA calculations and compare their predictions to experimental data. Finally we use these calculations to predict the 2{nu} double-{beta}-decay rate of {sup 116}Cd to the ground and excited states of {sup 116}Sn. {copyright} {ital 1998} {ital The American Physical Society}