Search for a new kind of superfluidity built on collective proton-neutron pairs with aligned spin is performed studying the Gamow-Teller decay of the T=1, Jπ=0+ ground state of Ge62 into excited states of the odd-odd N=Z nucleus Ga62. The experiment is performed at GSI Helmholtzzentrum für Shwerionenforshung with the Ge62 ions selected by the fragment separator and implanted in a stack of Si-strip detectors, surrounded by the RISING Ge array. A half-life of T1/2=82.9(14)ms is measured for the Ge62 ground state. Six excited states of Ga62, populated below 2.5 MeV through Gamow-Teller transitions, are identified. Individual Gamow-Teller transition strengths agree well with theoretical predictions of the interacting shell model and the quasiparticle random phase approximation. The absence of any sizable low-lying Gamow-Teller strength in the reported beta-decay experiment supports the hypothesis of a negligible role of coherent T=0 proton-neutron correlations in Ga62. © 2014 American Physical Society.

The present work has been supported by the Generalitat Valenciana, Spain, under Grant No. PROMETEO/2010/ 101 and by MINECO, Spain, under Grants No. AIC-D- 2011-0746, No. FPA2011-29854, No. FIS2011-23565, No. FPA2011-24553, and No. SEV-2012-0249. The experimental activity has been partially supported by the EU under the FP6-Integrated Infrastructure Initiative EURONS, Contract No. RII3-CT-2004-506065, FP7- Integrated Infrastructure Initiative ENSAR, Grant No. 262010, and the Science and Technology Facilities Council (UK), the Swedish Science Council, Istanbul University Scientific Research Projects, No. 21658, and OTKA Contract No. K100835.

E. Grodner et al. ; 5 pags. ; 4 figs. ; 1 tab. ; PACS numbers: 21.60.Cs, 23.20.Lv, 23.40.−s

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