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Quasifree (p, 2p) Reactions on Oxygen Isotopes: Observation of Isospin Independence of the Reduced Single-Particle Strength



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Fraile Prieto, Luis Mario and Otros, ... (2018) Quasifree (p, 2p) Reactions on Oxygen Isotopes: Observation of Isospin Independence of the Reduced Single-Particle Strength. Physical review letters, 120 (5). ISSN 0031-9007

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Official URL: http://dx.doi.org/10.1103/PhysRevLett.120.052501


Background: For many years, quasifree scattering reactions in direct kinematics have been extensively used to study the structure of stable nuclei, demonstrating the potential of this approach. The (RB)-B-3 collaboration has performed a pilot experiment to study quasifree scattering reactions in inverse kinematics for a stable C-12 beam. The results from that experiment constitute the first quasifree scattering results in inverse and complete kinematics. This technique has lately been extended to exotic beams to investigate the evolution of shell structure, which has attracted much interest due to changes in shell structure if the number of protons or neutrons is varied. Purpose: In this work we investigate for the first time the quasifree scattering reactions (p, pn) and (p, 2p) simultaneously for the same projectile in inverse and complete kinematics for radioactive beams with the aim to study the evolution of single-particle properties from N = 14 to N = 15. Method: The structure of the projectiles O-23, O-22, and N-21 has been studied simultaneously via (p, pn) and (p, 2p) quasifree knockout reactions in complete inverse kinematics, allowing the investigation of proton and neutron structure at the same time. The experimental data were collected at the (RB)-B-3-LAND setup at GSI at beam energies of around 400 MeV/u. Two key observables have been studied to shed light on the structure of those nuclei: the inclusive cross sections and the corresponding momentum distributions. Conclusions: The knockout reactions (p, pn) and (p, 2p) with radioactive beams in inverse kinematics have provided important and complementary information for the study of shell evolution and structure. For the (p, pn) channels, indications of a change in the structure of these nuclei moving from N = 14 to N = 15 have been observed, i.e., from the 0d(5/2) shell to the 1s(1/2). This supports previous observations of a subshell closure at N = 14 for neutron-rich oxygen isotopes and its weakening for the nitrogen isotopes.

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© 2018 American Physical Society.
Artículo firmado por más de 10 autores.
We thank the FRS and GSI accelerator staff for their work. This work was supported by the Swedish Research Council and by the Spanish Ministerio by the projects FPA2009-14604-C02-01/FPA2012-39404-C02-01/FPA2013-478 831-C2-1 and NuPNET ERA-NET within the NuPNET GANAS project, under Grant Agreement No. 202914 and from the European Union, within the "7th Framework Program" FP7/2007-2013, under Grant Agreement No. 262010 ENSAR-INDESYS. This work was supported by the German Federal Ministry for Education and Research (BMBF Project No. 05P15RDFN1), and through the GSI-TU Darmstadt cooperation agreement. The work of R.C. and E.C. is supported by Fundacao para a Ciencia e Tecnologia (FCT) of Portugal under Contract No. PTD/FIS-NUC/2240/2014. The work of A.D. and D.J. was supported by Lietuvos Mokslo Taryba (Research Council of Lithuania) under Contract No. MIP-094/2015. A.M.M. is supported by the Spanish Ministerio de Economia y Competitividad under Project No. FIS2014-53448-C2-1-P and by the European Unions Horizon 2020 research and innovation program under Grant Agreement No. 654002. C.B. is supported by the US DOE Award No. DE-FG02-08ER41533 and the US NSF Grant No. 1415656. This work was supported by the Portuguese FCT, Project No. PTDC/FIS/103902/2008. The work of O.T. was supported by FPA2012-32443, FPA2015-64969-P, and ENSAR2 project of H2020 with Grant Agreement No. 654002. L.M.F. acknowledges funding from the Ministerio de Economia, Industria y Competitividad de Espana, MINECO under Project No. FPA2015-65035-P.

Uncontrolled Keywords:Nuclear matter; Knockout; Systems; Model; O-16.
Subjects:Sciences > Physics > Nuclear physics
ID Code:47042
Deposited On:09 Apr 2018 10:00
Last Modified:10 Dec 2018 14:57

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