Orateur
Prof.
Eduardo Garrido
(Instituto de Estructura de la Materia, CSIC, Madrid, Spain)
Description
Stellar nucleosynthesis reactions are responsible for the abundances of the different
elements in the Universe. These reactions happen at very low relative energies between the
nuclei involved, and the calculation of the corresponding production rates is one
of major issues in Nuclear Astrophysics. These reactions can be of different nature (radiative
capture, rearrangement processes...) and very often can be described as few-body processes.
In this talk we describe how to compute the production rates for three-body radiative capture
reactions, using the alpha+n+n --> 6He + gamma process as an example. The calculation includes
sequential processes (where an intermediate 5He resonance is populated) as well as direct
capture of the two neutrons by the alpha particle. This production rate is compared to the
estimated one for the four-body recombination process, alpha+n+n+n --> 6He + n, which compete
with the radiative two-neutron capture as a source of 6He. For rearrangement reactions, where the
initial nuclei can recombine themselves to produce different final products, we propose the use
of the adiabatic approximation as an efficient procedure to distinguish between the different
reaction channels, being at the same time possible to compute the transition probabilities at
the required very low relative energies.
Auteur principal
Prof.
Eduardo Garrido
(Instituto de Estructura de la Materia, CSIC, Madrid, Spain)
