Seminarium Fizyki Jądra Atomowego
sala 1.01, ul. Pasteura 5
Dr Gagandeep Singh (National Centre for Nuclear Research)
Low and medium mass neutron halos
The nuclear chart is full of phenomena hitherto unexplained. Of the roughly estimated 7000 nuclear species to exist in nature, only about 10% are known and studied. Owing to the Coulomb barrier, most of these lie on the neutron rich side of the valley of stability. Halos are a special class of these exotic nuclei where one or two nucleons decouple from a composite core and penetrate the classically forbidden region. They are weakly bound nuclei, with the continuum playing a major role in their description. I discuss the three-body Borromean system 31F, which is the last known isotope of the Fluorine chain and has been deemed as a p-wave halo, using a pseudostate approach with a transformed harmonic oscillator (THO) basis. Similarly, 34Na, analyzed using the post form finite range distorted wave Born approximation (FRDWBA) theory is a vital p-wave halo like 31F, but is a one-neutron halo candidate whose formation rate is crucial to 35Na, the most abundant neutron rich isotope of the Sodium chain. With the same basis discretizing the intermediate continuum as 31F, I then discuss two-neutron transfer reactions with 6He as an ideal candidate to understand the reaction mechanism due to the pairing interactions in the final nucleus. I weigh up scattering of the Cooper pair of the nucleons via the different states of the intermediate continuum through comparisons with a hypothetical bound case of 5He. Extending the possibilities for astrophysical applications, reaction rates for radiative neutron capture (n,γ) reactions involving some of these exotic nuclei would also be discussed.


