DOI: 10.1140/epja/i2002-10131-8
Lifetime of heavy hypernuclei and its implications on the weak
interaction
W. Cassing1, L. Jarczyk2, B. Kamys2, P. Kulessa3, 4, H. Ohm3, K. Pysz3, 4, Z. Rudy2, 3, O.W.B. Schult3 and H. Ströher3
1 Institut für Theoretische Physik, Justus Liebig Universität Giessen, D-35392 Giessen, Germany
2 M. Smoluchowski Institute of Physics, Jagellonian University, PL-30059 Cracow, Poland
3 Institut für Kernphysik, Forschungszentrum Jülich, D-52425 Jülich, Germany
4 H. Niewodniczanski Institute of Nuclear Physics, PL-31342 Cracow, Poland
h.stroeher@fz-juelich.de
(Received: 8 August 2002 / Revised version: 20 December 2002 / Published online: 25 March 2003)
Abstract
The lifetime of the
-hyperon in heavy
hypernuclei measured in proton-Au, -Bi and -U collisions
by the COSY-13 Collaboration at COSY-Jülich has been
analyzed to yield
) ps. This value
for
is compatible with the lifetime extracted
from antiproton annihilation on Bi and U targets, albeit much
more accurate. Theoretical models based on the meson exchange
picture and assuming the validity of the phenomenological
rule predict the lifetime of heavy hypernuclei to be
significantly larger (2-3 standard deviations). Such large
differences indicate that at least one of the assumptions in
these models is not fulfilled. A much better reproduction of the
lifetimes of heavy hypernuclei is achieved in the phase space model,
if the
rule is discarded in the nonmesonic
decay.
13.30.-a - Decays of baryons.
13.75.Ev - Hyperon-nucleon interactions.
21.80.+a - Hypernuclei.
25.80.Pw - Hyperon-induced reactions.
© Società Italiana di Fisica, Springer-Verlag 2003