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HK: Fachverband Physik der Hadronen und Kerne

HK 5: Structure and Dynamics of Nuclei I

HK 5.5: Vortrag

Montag, 14. März 2016, 15:15–15:30, S1/01 A03

Observation and spectroscopy of new proton-unbound isotopes ³⁰Ar and ²⁹Cl – an interplay of prompt two-proton and sequential decay — •Ivan Mukha — Helmholzzentrum GSI, Darmstadt

Previously unknown isotopes ³⁰Ar and ²⁹Cl have been identified by measurement of the trajectories of their in-flight decay products ²⁸S+p+p and ²⁸S+p, respectively. The analysis of angular correlations of the fragments provided information on decay energies and structure of the parent states [1]. The lowest states in ³⁰Ar, ²⁹Cl point to a violation of isobaric symmetry in structure of these unbound nuclei. The two-proton decay has been identified in a transition region between simultaneous two-proton and sequential proton emissions from the ³⁰Ar ground state, which is characterized by an interplay of three-body and two-body decay mechanisms. Such a phenomenon, never observed before, may be common in 2p-unbound nuclei, and could be of interest for other disciplines dealing with few-body systems. In addition, the dramatic change of odd-even mass staggering in 2p-unbound nuclei and the fine structure in the 2p decay of the ³⁰Ar^*(2.9 MeV) state were indicated. An Optical Time-Projection Chamber was used in the same experiment to observe beta decays of stopped ³¹Ar ions, which passed the secondary target intact. With this detector, β-delayed 3p emission from ³¹Ar was observed [2].

[1] I. Mukha, et al., Phys. Rev. Lett. 115 (2015) 202501.

[2] A.A. Lis, et al., Phys. Rev. C 91 (2015) 064309.