Asymmetry parameter for nonmesonic hypernuclear decay

Nenhuma Miniatura disponível




Barbero, Cesar
Galeão, Alfredo P. [UNESP]
Krmpotić, Francisco

Título da Revista

ISSN da Revista

Título de Volume



We give general expressions for the vector asymmetry in the angular distribution of protons in the nonmesonic weak decay of polarized hypernuclei. From these we derive an explicit expression for the calculation of the asymmetry parameter, aÎ, which is applicable to the specific cases of Î 5He and Î 12C described within the extreme shell model. In contrast to the approximate formula widely used in the literature, it includes the effects of three-body kinematics in the final states of the decay and correctly treats the contribution of transitions originating from single-proton states beyond the s-shell. This expression is then used for the corresponding numerical computation of aÎ within several one-meson-exchange models. Besides the strictly local approximation usually adopted for the transition potential, we also consider the addition of the first-order nonlocality terms. We find values for aÎ ranging from -0.62 to -0.24, in qualitative agreement with other theoretical estimates but in contradiction with some recent experimental determinations. © 2005 The American Physical Society.



Como citar

Physical Review C - Nuclear Physics, v. 72, n. 3, 2005.