s-Wave Approximation for Asymmetry in Nonmesonic Decay of Finite Hypernuclei

C. BARBERO, A. P. GALEÃO, F. KRMPOTIC

PHYS. REV. - C

The American Physical Society.

Lugar: New York; Año: 2007 vol. 76 p. 543211 - 543218

0556-2813

We establish the bridge between the commonly usedNabetani-Ogaito-Sato-Kishimoto (NOSK)   formula for the asymmetryparameter $a_Lambda$ in the  $vecLambda p ightarrow np$emission of polarized  hypernuclei, and the shell model (SM) formalism for finite hypernuclei.We demonstrate that  the s-wave approximation leads to a SMformula   for $a_Lambda$ that is as simple as the NOSK one, andthat  reproduces the exact results for $^5_Lambda$He and$^{12}_Lambda$C better than initially expected. The simplicityachieved here is indeed remarkable. The new formalism makes thetheoretical evaluation of  $a_Lambda$ more transparent, andexplains clearly why the one-meson exchange model is unable toaccount for the  experimental data of $^5_Lambda$He.