s-wave approximation for asymmetry in nonmesonic decay of finite hypernuclei

C. BARBERO, A.P. GALEAO Y F. KRMPOTIC

Physical Review C

American Physical Society

Año: 2007 vol. 76 p. 543211 - 543218

0556-2813

We establish the bridge between the commonly used Nabetani-Ogaito-Sato-Kishimoto (NOSK)   formula for the asymmetry parameter a_Lambda in the  Lambda p -> np  emission of polarized  hypernuclei, and the shell model (SM) formalism for finite hypernuclei. We demonstrate that  the s-wave approximation leads to a SM formula  for a_Lambda that is as simple as the NOSK one, and that  reproduces the exact results for ^5_Lambda He and ^{12}_Lambda C better than initially expected. The simplicity achieved here is indeed remarkable. The new formalism makes the theoretical evaluation of  a_Lambda more transparent, and explains clearly why the one-meson exchange model is unable to account for the  experimental data of ^5_Lambda He.