title: Proton Distribution Radii of ^{12-19}C Illuminate Features of Neutron Halos.
abstract: Proton radii of ^{12-19}C densities derived from first accurate charge changing cross section measurements at 900A  MeV with a carbon target are reported. A thick neutron surface evolves from ∼0.5  fm in ^{15}C to ∼1  fm in ^{19}C. The halo radius in ^{19}C is found to be 6.4±0.7  fm as large as ^{11}Li. Ab initio calculations based on chiral nucleon-nucleon and three-nucleon forces reproduce the radii well.
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authors.affiliation: Department of Physics, Hokkaido University, Sapporo 060-0810, Japan.
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authors.affiliation: Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.|National Center for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 USA.
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authors.affiliation: GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany.
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authors.affiliation: Universidad de Santiago de Compostela, E-15706 Santiago de Compostella, Spain.
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authors.affiliation: GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany.
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authors.affiliation: Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada.|GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany.
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authors.affiliation: GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany.
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authors.affiliation: GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany.
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authors.affiliation: GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany.|Justus-Liebig University, 35392 Giessen, Germany.
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authors.affiliation: GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany.
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authors.affiliation: Department of Physics, Hokkaido University, Sapporo 060-0810, Japan.
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authors.affiliation: GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany.
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authors.affiliation: GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany.
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authors.affiliation: GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany.
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authors.affiliation: GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany.
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authors.affiliation: Universidad de Santiago de Compostela, E-15706 Santiago de Compostella, Spain.
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authors.affiliation: GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany.
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authors.affiliation: GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany.
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authors.affiliation: GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany.
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authors.affiliation: GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany.
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authors.affiliation: GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany.|Justus-Liebig University, 35392 Giessen, Germany.
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authors.affiliation: Faculty of Mathematics and Physics, Comenius University, 84215 Bratislava, Slovakia.
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authors.affiliation: Faculty of Mathematics and Physics, Comenius University, 84215 Bratislava, Slovakia.
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authors.affiliation: RIKEN Nishina Center, Wako, Saitama 351-0198, Japan.|Department of Physics, Niigata University, Niigata 950-2181, Japan.
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authors.affiliation: GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany.
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authors.affiliation: RCNP, Osaka University, Mihogaoka, Ibaraki, Osaka 567 0047, Japan.|School of Physics and Nuclear Energy Engineering and IRCNPC, Beihang University, Beijing 100191, People's Republic of China.
authors.forename: I
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authors.affiliation: School of Physics and Nuclear Energy Engineering and IRCNPC, Beihang University, Beijing 100191, People's Republic of China.
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authors.affiliation: Universidad de Santiago de Compostela, E-15706 Santiago de Compostella, Spain.
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authors.affiliation: GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany.
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authors.affiliation: GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany.
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