Beta decay to continuum states: the case of11Be

Karsten Riisager,S Lunardi,C Bucci,P Di Nezza,C Signorini,J.J Valiente-Dobon,A Nannini,P.G Bizzeti,R Menegazzo,A Dainese,M Chiari

doi:10.1051/epjconf/20146602090

Abstract

Beta decay in exotic nuclei can lead to multi-particle final states. This contri- bution discusses briefly what decay mechanisms may enter in such decays and presents, on behalf of the IS541 collaboration at ISOLDE/CERN, preliminary data from a search for the beta-delayed proton decay of the halo nucleus 11 Be.

Highlights

Some indication for decays going directly into the continuum exist for halo nuclei, see [3,4,5] and references therein for details on the halo structure
A complicating factor in the theoretical description of these two decays is the “two neutron to deuteron” overlap that is sensitive to the correlations between the two neutrons. This is an interesting physics problem, but if the focus is on investigating the decay mechanism a much cleaner case would be the beta-delayed proton decay of a single-neutron halo nucleus
The IS374 experiment made sample collections in 2001 and the amount of remaining 10Be in the samples were determined in an accelerator mass spectromery (AMS) experiment in Uppsala in 2008, details of the experimental procedures can be found in a recent paper [7]

Summary

Beta-particle decay mechanism

The Q-values for beta-decays increase as one moves towards the driplines and eventually become larger than the particle separation energies in the daughter nuclei This allows population of final states containing, apart from the beta particle and the associated (anti)neutrino, one or more particles (protons, neutrons or heavier particles) in continuum states and a recoiling final nucleus. A complicating factor in the theoretical description of these two decays is the “two neutron to deuteron” overlap that is sensitive to the correlations between the two neutrons This is an interesting physics problem, but if the focus is on investigating the decay mechanism a much cleaner case would be the beta-delayed proton decay of a single-neutron halo nucleus.

The IS374 experiment

The IS541 experiment

Discussion and outlook