Studies of continuum states in 16 Ne using three-body correlation techniques

J. Marganiec; F. Wamers; F. Aksouh; Yu. Aksyutina; H. Álvarez-Pol; T. Aumann; S. Beceiro-Novo; K. Boretzky; M. J. G. Borge; M. Chartier; A. Chatillon; L. V. Chulkov; D. Cortina-Gil; H. Emling; O. Ershova; L. M. Fraile; H. O. U. Fynbo; D. Galaviz; H. Geissel; M. Heil; D. H. H. Hoffmann; J. Hoffmann; H. T. Johansson; B. Jonson; C. Karagiannis; O. A. Kiselev; J. V. Kratz; R. Kulessa; N. Kurz; C. Langer; M. Lantz; T. Le Bleis; R. Lemmon; Yu. A. Litvinov; K. Mahata; C. Müntz; T. Nilsson; C. Nociforo; G. Nyman; W. Ott; V. Panin; S. Paschalis; A. Perea; R. Plag; R. Reifarth; A. Richter; C. Rodriguez-Tajes; D. Rossi; K. Riisager; D. Savran; G. Schrieder; H. Simon; J. Stroth; K. Sümmerer; O. Tengblad; H. Weick; M. Wiescher; C. Wimmer; M. V. Zhukov

doi:10.1140/epja/i2015-15009-0

2022 Impact factor 2.7

Hadrons and Nuclei

Eur. Phys. J. A (2015) 51: 9
https://doi.org/10.1140/epja/i2015-15009-0

Regular Article - Experimental Physics

Studies of continuum states in ¹⁶ Ne using three-body correlation techniques

J. Marganiec¹^,2^,3, F. Wamers¹^,2^,3^,4, F. Aksouh²^,a, Yu. Aksyutina², H. Álvarez-Pol⁵, T. Aumann¹^,2, S. Beceiro-Novo⁵, K. Boretzky², M. J. G. Borge⁶^,7, M. Chartier⁸, A. Chatillon², L. V. Chulkov²^,9, D. Cortina-Gil⁵, H. Emling², O. Ershova²^,10, L. M. Fraile¹¹, H. O. U. Fynbo¹², D. Galaviz⁷, H. Geissel², M. Heil², D. H. H. Hoffmann¹, J. Hoffmann², H. T. Johansson¹³, B. Jonson¹³, C. Karagiannis², O. A. Kiselev², J. V. Kratz¹⁴, R. Kulessa¹⁵, N. Kurz², C. Langer²^,10, M. Lantz¹⁶, T. Le Bleis²^,17, R. Lemmon¹⁸, Yu. A. Litvinov², K. Mahata²^,19, C. Müntz², T. Nilsson¹³, C. Nociforo², G. Nyman¹³, W. Ott², V. Panin¹^,2, S. Paschalis¹^,8, A. Perea⁷, R. Plag²^,10, R. Reifarth²^,10, A. Richter¹, C. Rodriguez-Tajes⁵, D. Rossi²^,b, K. Riisager¹², D. Savran³^,4, G. Schrieder¹, H. Simon², J. Stroth¹⁰, K. Sümmerer², O. Tengblad⁷, H. Weick², M. Wiescher²⁰, C. Wimmer²^,10 and M. V. Zhukov¹³

¹ Institut für Kernphysik, Technische Universität Darmstadt, D-64289, Darmstadt, Germany
² GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291, Darmstadt, Germany
³ ExtreMe Matter Institute EMMI, Research Division GSI, D-64291, Darmstadt, Germany
⁴ Frankfurt Institute for Advanced Studies FIAS, D-60438, Frankfurt am Main, Germany
⁵ Grupo de Física Nuclear, Universidade de Santiago de Compostela, ES-15782, Santiago de Compostela, Spain
⁶ ISOLDE-EP, CERN, CH-1211, Geneva, Switzerland
⁷ Instituto de Estructura de la Materia, CSIC, ES-28006, Madrid, Spain
⁸ Department of Physics, University of Liverpool, L69 3BX, Liverpool, UK
⁹ Kurchatov Institute, RU-123182, Moscow, Russia
¹⁰ Institut für Angewandte Physik, Goethe Universität, D-60438, Frankfurt am Main, Germany
¹¹ Grupo de Física Nuclear, FAMN, Universidad Complutense de Madrid, CEI Moncloa, ES-28040, Madrid, Spain
¹² Department of Physics and Astronomy, University of Aarhus, DK-8000, Aarhus, Denmark
¹³ Fundamental Fysik, Chalmers Tekniska Högskola, SE-412 96, Göteborg, Sweden
¹⁴ Institut für Kernchemie, Johannes Gutenberg-Universität Mainz, D-55122, Mainz, Germany
¹⁵ Instytut Fizyki, Uniwersytet Jagelloński, PL-30-059, Krakóv, Poland
¹⁶ Institutionen för fysik och astronomi, Uppsala Universitet, SE-75120, Uppsala, Sweden
¹⁷ Physik-Department E12, Technische Universität München, D-85748, Garching, Germany
¹⁸ Nuclear Physics Group, STFC Daresbury Lab, Warrington, WA44AD, Cheshire, UK
¹⁹ Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai-400 085, Trombay, India
²⁰ JINA, University of Notre Dame, 46556, Notre Dame, IN, USA

Received: 23 October 2014
Revised: 20 January 2015
Accepted: 21 January 2015
Published online: 28 January 2015

Abstract

Two-proton decay of the unbound $ T_{z} =-2$ nucleus ¹⁶Ne , produced in one-neutron knockout from a 500 MeV/u ¹⁷Ne beam, has been studied at GSI. The ground state, at a resonance energy 1.388(15) MeV, ( $ \Gamma =0.082(15)$ MeV) above the ¹⁴O +p+p threshold, and two narrow resonances at $ E_{r} =3.220(46)$ MeV and 7.57(6) MeV have been investigated. A comparison of the energy difference between the first excited 2⁺ state and the 0⁺ ground state in ¹⁶Ne with its mirror nucleus ¹⁶C reveals a small Thomas-Ehrman shift (TES) of $ +70(46)$ keV. A trend of the TES for the T = 2 quintet is obtained by completing the known data with a prediction for ¹⁶F obtained from an IMME analysis. The decay mechanisms of the observed three resonances were revealed from an analysis of the energy and angular correlations of the ¹⁴O +p+p decay products. The ground state decay can be considered as a genuine three-body (democratic) mode and the excited states decay sequentially via states in the intermediate nucleus ¹⁵F , the 3.22 MeV state predominantly via the ¹⁵F ground-state resonance, while the 7.57 MeV state decays via the 5/2⁺ resonance in ¹⁵F at 2.8 MeV above the ¹⁴O +p+p threshold. Further, from an analysis of angular correlations, the spin-parity of the 7.57 MeV state has been determined as $ I^{\pi} =2^{+}$ and assigned as the third 2⁺ state in ¹⁶Ne based on a comparison with ¹⁶C.