Matter radius of the doubly-magic $$^{56}$$Ni measured in a storage ring
M. von Schmid, T. Aumann, S. Bagchi, S. Bönig, M. Csatlós, I. Dillmann, Christina Dimopoulou, P. Egelhof, V. Eremin, T. Furuno, H. Geißel, R. Gernhäuser, M.N. Harakeh, A.-L. Hartig, S. Ilieva, N. Kalantar‐Nayestanaki, O. Kiselev, H. Kollmus, C. Kozhuharov, A. Krasznahorkay, Th. Kröll, M. Kuilman, S. Litvinov, Yu. A. Litvinov, M. Mahjour‐Shafiei, M. Mutterer, D. Nagae, M. A. Najafi, C. Nociforo, F. Nolden, U. Popp, C. Rigollet, Robert Roth, S. Roy, C. Scheidenberger, M. Steck, B. Štreicher, L. Stuhl, M. Thürauf, Т. Уесака, H. Weick, J. S. Winfield, D. Winters, P. J. Woods, Takayuki Yamaguchi, K. Yue, J. C. Cardona, J. Zenihiro
Abstract
Abstract The matter radius of the doubly magic $$^{56}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow/><mml:mn>56</mml:mn></mml:msup></mml:math> Ni was extracted from a measurement of the differential cross section by employing, for the first time, elastic proton scattering in inverse kinematics with a radioactive beam at $$E_{kin}=390.2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>E</mml:mi><mml:mrow><mml:mi>kin</mml:mi></mml:mrow></mml:msub><mml:mo>=</mml:mo><mml:mn>390.2</mml:mn></mml:mrow></mml:math> MeV/nucleon circulating in a storage ring and passing an internal hydrogen gas-jet target with a revolution frequency of around 2 MHz. The novel experimental scheme is based on UHV-compatible Si detectors operated as active vacuum windows, which were implemented in the ESR storage ring at GSI. A matter radius $$<r_{m}^{2}>^{1/2}=3.74^{+0.03}_{-0.06}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mo><</mml:mo><mml:msubsup><mml:mi>r</mml:mi><mml:mrow><mml:mi>m</mml:mi></mml:mrow><mml:mn>2</mml:mn></mml:msubsup><mml:msup><mml:mo>></mml:mo><mml:mrow><mml:mn>1</mml:mn><mml:mo>/</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:msup><mml:mo>=</mml:mo><mml:mn>3</mml:mn><mml:mo>.</mml:mo><mml:msubsup><mml:mn>74</mml:mn><mml:mrow><mml:mo>-</mml:mo><mml:mn>0.06</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.03</mml:mn></mml:mrow></mml:msubsup></mml:mrow></mml:math> fm was extracted for the doubly-magic self-conjugate nucleus $$^{56}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow/><mml:mn>56</mml:mn></mml:msup></mml:math> Ni.