Eur. Phys. J. A 16, 549-561 (2003)
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. Kulessa^{3, 4}, H. Ohm³, K. Pysz^{3, 4}, Z. Rudy^{2, 3}, O.W.B. Schult³ and H. Ströher<sup>3

1</sup>  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.

PACS
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