Halflife of $^{56}$Ni in cosmic rays

J. Lund Fisker; G. Martínez-Pinedo; K. Langanke

doi:doi:10.1007/s100500050277

EPJ

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2024 Impact factor 2.8

Hadrons and Nuclei

Eur. Phys. J. A 5, 229-231

Halflife of ⁵⁶Ni in cosmic rays

J. Lund Fisker - G. Martínez-Pinedo - K. Langanke

Institute of Physics and Astronomy, University of Århus, Denmark

Received: 23 February 1999 Communicated by A. Schäfer

Abstract
A measurement of the ⁵⁶Ni cosmic ray abundance has been discussed as a possible tool to determine the acceleration time scale of relativistic particles in cosmic rays. This conjecture will depend on the halflife of totally ionized ⁵⁶Ni which can only decay by higher-order forbidden transitions. We have calculated this halflife within large-scale shell model calculations and find $t_{1/2} \approx 4 \times 10^4$ years, only slightly larger than the currently available experimental lower limit, but too short for ⁵⁶Ni to serve as a cosmic ray chronometer.

PACS
23.40.-s Beta decay; double beta decay; electron and muon capture - 23.40.Hc Relation with nuclear matrix elements and nuclear structure - 21.60.Cs Shell model - 27.40.+z $39\leq A \leq 58$ - 98.70.Sa Cosmic rays