Antiproton annihilation on light nuclei at very low energies
K.V. Protasov1 - G. Bonomi2 - E. Lodi Rizzini2 - A. Zenoni2
1 Institut des Sciences Nucléaires, IN2P3-CNRS, UJFG, 53, Avenue des Martyrs, 38026
Grenoble, Cedex, France
2 Dipartimento di Chimica e Fisica per l'Ingegneria e per i Materiali, Università di Brescia and INFN
Sez. di Pavia, Via Valotti 9, 25123 Brescia, Italy
Received: 3 November 1999 / Revised version: 15 December 1999 Communicated by Th. Walcher
Abstract
Recent experimental data obtained by the OBELIX collaboration
on pD and p4He total annihilation cross
sections are analyzed. The combined analysis of these data with
existing antiprotonic atom data allows, for the first time,
the imaginary parts of the S-wave scattering lengths for the two nuclei to be
extracted.
The obtained values are:
![$\mbox {Im } a^{sc}_0 = [- 0.62 \pm 0.02 (\mbox{stat}) \pm 0.04
(\mbox{sys})]
\mbox { fm}$](/articles/epja/abs/2000/03/epja208/img1.gif){kind=small}
for pD
and
![$\mbox {Im } a^{sc}_0 = [- 0.36\pm
0.03(\mbox{stat})^{+0.19}_{-0.11}(\mbox{sys})]
\mbox { fm}$](/articles/epja/abs/2000/03/epja208/img2.gif){kind=small}
for
He.
This analysis indicates an unexpected behaviour of
the imaginary part of the p-nucleus S-wave scattering
length as a function of the atomic weight A:
(pp) >
(pD)
>
(p4He).
PACS
25.43.+t Antiproton-induced reactions -
36.10.-k Exotic atoms and molecules
Copyright Società Italiana di Fisica, Springer-Verlag 2000
