title: Experimental study of the two-body spin-orbit force in nuclei.
abstract: Energies and spectroscopic factors of the first 7/2-, 3/2-, 1/2-, and 5/2- states in the (35)Si21 nucleus were determined by means of the (d, p) transfer reaction in inverse kinematics at GANIL using the MUST2 and EXOGAM detectors. By comparing the spectroscopic information on the Si35 and S37 isotones, a reduction of the p3/2-p1/2 spin-orbit splitting by about 25% is proposed, while the f7/2-f5/2 spin-orbit splitting seems to remain constant. These features, derived after having unfolded nuclear correlations using shell model calculations, have been attributed to the properties of the two-body spin-orbit interaction, the amplitude of which is derived for the first time in an atomic nucleus. The present results, remarkably well reproduced by using several realistic nucleon-nucleon forces, provide a unique touchstone for the modeling of the spin-orbit interaction in atomic nuclei.
authors.affiliation: Grand Accélérateur National d'Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, BP 55027, F-14076 Caen Cedex 5, France.
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authors.affiliation: Grand Accélérateur National d'Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, BP 55027, F-14076 Caen Cedex 5, France.
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authors.affiliation: IPHC, CNRS/IN2P3, Université de Strasbourg, F-67037 Strasbourg, France.
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authors.affiliation: Institut de Physique Nucléaire, CNRS/IN2P3, Université Paris-Sud, F-91406 Orsay, France.
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authors.affiliation: Institut de Physique Nucléaire, CNRS/IN2P3, Université Paris-Sud, F-91406 Orsay, France.
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authors.affiliation: IPHC, CNRS/IN2P3, Université de Strasbourg, F-67037 Strasbourg, France.
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authors.affiliation: Institut de Physique Nucléaire, CNRS/IN2P3, Université Paris-Sud, F-91406 Orsay, France.
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authors.affiliation: Institut de Physique Nucléaire, CNRS/IN2P3, Université Paris-Sud, F-91406 Orsay, France.
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authors.affiliation: Grand Accélérateur National d'Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, BP 55027, F-14076 Caen Cedex 5, France.
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authors.affiliation: Grand Accélérateur National d'Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, BP 55027, F-14076 Caen Cedex 5, France.
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authors.affiliation: IPHC, CNRS/IN2P3, Université de Strasbourg, F-67037 Strasbourg, France.
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authors.affiliation: Grand Accélérateur National d'Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, BP 55027, F-14076 Caen Cedex 5, France and Department of Particle Physics, Universidade de Santiago de Compostela, E-15782, Santiago de Compostela, Spain.
authors.forename: B
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authors.lastname: Fernandez-Dominguez
authors.affiliation: CEA Saclay, IRFU, Service de Physique Nucléaire, F-91191 Gif-sur-Yvette, France.
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authors.initials: F
authors.lastname: Flavigny
authors.affiliation: Institut de Physique Nucléaire, CNRS/IN2P3, Université Paris-Sud, F-91406 Orsay, France.
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authors.affiliation: LPC Caen, ENSICAEN, Université de Caen, CNRS/IN2P3, F14050 CAEN Cedex, France.
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authors.affiliation: CEA Saclay, IRFU, Service de Physique Nucléaire, F-91191 Gif-sur-Yvette, France.
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authors.affiliation: Grand Accélérateur National d'Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, BP 55027, F-14076 Caen Cedex 5, France and Centre d Études Nucléaires de Bordeaux Gradignan-Université Bordeaux 1-UMR 5797 CNRS/IN2P3, Chemin du Solarium, BP 120, 33175 Gradignan, France.
authors.forename: S
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authors.affiliation: Institut de Physique Nucléaire, CNRS/IN2P3, Université Paris-Sud, F-91406 Orsay, France.
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authors.affiliation: Grand Accélérateur National d'Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, BP 55027, F-14076 Caen Cedex 5, France.
authors.forename: A
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authors.affiliation: Institut de Physique Nucléaire, CNRS/IN2P3, Université Paris-Sud, F-91406 Orsay, France.
authors.forename: I
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authors.affiliation: Institut de Physique Nucléaire, CNRS/IN2P3, Université Paris-Sud, F-91406 Orsay, France and Department of Physics, University of Surrey, Guildford GU2 5XH, United Kingdom.
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authors.affiliation: CEA Saclay, IRFU, Service de Physique Nucléaire, F-91191 Gif-sur-Yvette, France.
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authors.affiliation: CEA Saclay, IRFU, Service de Physique Nucléaire, F-91191 Gif-sur-Yvette, France.
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authors.affiliation: Department of Physics and Center for Nuclear Study, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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authors.affiliation: Grand Accélérateur National d'Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, BP 55027, F-14076 Caen Cedex 5, France.
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authors.affiliation: Grand Accélérateur National d'Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, BP 55027, F-14076 Caen Cedex 5, France and Instituut voor Kern-en Stralingsfysica, KU Leuven, Leuven, Belgium.
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authors.affiliation: CSNSM-IN2P3-CNRS, Université Paris-Sud, 91405 Orsay, France.
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authors.affiliation: Institut de Physique Nucléaire, CNRS/IN2P3, Université Paris-Sud, F-91406 Orsay, France.
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authors.affiliation: Grand Accélérateur National d'Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, BP 55027, F-14076 Caen Cedex 5, France.
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authors.affiliation: Grand Accélérateur National d'Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, BP 55027, F-14076 Caen Cedex 5, France.
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