INVESTIGADORES
BARBERO Cesar Alberto
artículos
Título:
Influence of DeltaT=3/2 terms on s- and p-shell contributions to the asymmetry parameter of Lambda p -> np decay
Autor/es:
C. BARBERO
Revista:
NUCLEAR PHYSICS A
Editorial:
Elsevier
Referencias:
Lugar: Amsterdam; Año: 2007 vol. 785 p. 339 - 350
ISSN:
0375-9474
Resumen:
Here is evaluated the effect of the Delta T= 3/2
isospin terms of weak interaction on the asymmetry parameter, a_Lambda, for
proton induced nonmesonic hypernuclear weak decay, Lambda p -> np.
There has been used a general shell model formalism for finite hypernuclei
recently developed. A strangeness-changing weak transition potential including
the exchange of pseudoscalar mesons (pion, eta, K) is adopted. The effects of
Delta T= 3/2 isospin changes have been included through an adequate
modification of the weak coupling constants. A comparison with Delta
T= 1/2 contribution is made for s and p-shell hypernuclei. It is
analytically shown and numerically corroborated for ^{12}_{Lambda}C and ^5_{Lambda}He
that Delta T= 3/2 terms affect approximately in the same percentage both s
and p-shell contributions to proton asymmetry parameter. The value of this
observable is increased in 4%. The effect of Delta T= 3/2 terms helps to
enhance the asymmetry parameter value, but is not enough to reproduce the
experimental data. The necessity of a similar detailed analysis including
vector meson exchange is suggested.