Eur. Phys. J. A 14, 279-285 (2002)
DOI: 10.1140/epja/i2002-10033-9

Short Note

First evidence for the two-proton decay of

M. Pfützner¹, E. Badura², C. Bingham³, B. Blank⁴, M. Chartier⁵, H. Geissel², J. Giovinazzo⁴, L.V. Grigorenko², R. Grzywacz¹, M. Hellström², Z. Janas¹, J. Kurcewicz¹, A.S. Lalleman⁴, C. Mazzocchi², I. Mukha², G. Münzenberg², C. Plettner², E. Roeckl², K.P. Rykaczewski^{6, 1}, K. Schmidt⁷, R.S. Simon², M. Stanoiu⁸ and J.-C. Thomas<sup>4

1</sup>  Institute of Experimental Physics, Warsaw University, PL-00-681 Warszawa, Poland
²  GSI, Planckstrasse 1, D-64291 Darmstadt, Germany
³  Department of Physics and Astronomy, University of Tennessee, Knoxville 37996 TN, USA
⁴  CEN Bordeaux-Gradignan, F-33175 Gradignan Cedex, France
⁵  Oliver Lodge Laboratory, Department of Physics, University of Liverpool, Liverpool, L69 3BX, UK
⁶  Physics Division, ORNL, Oak Ridge, TN 37831-6371, USA
⁷  Department of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, UK
⁸  GANIL, BP 5027, F-14021 Caen Cedex, France

pfutzner@mimuw.edu.pl

(Received: 17 May 2002 Communicated by J. Äystö)

Abstract
Decays of five ⁴⁵Fe atoms have been observed at the fragment separator of GSI. Whereas one event is consistent with the -decay of ⁴⁵Fe accompanied by the emission of a 10 MeV proton, four decays are consistent with the emission of particle(s) of total energy MeV. This observation represents the first evidence for two-proton ground-state radioactivity, a decay mode predicted for ⁴⁵Fe. The time distribution of the observed decay events corresponds to a half-life of 3.2^+2.6_-1.0 ms.

PACS
21.10.Tg - Lifetimes.
23.50.+z - Decay by proton emission.
29.30.Ep - Charged-particle spectroscopy.

© Società Italiana di Fisica, Springer-Verlag 2002