Hypernuclear Fine Structure in <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi>B</mi></mrow><mprescripts></mprescripts><mrow><mi>Λ</mi></mrow><mrow><mn>9</mn></mrow><mrow></mrow><mrow></mrow></mmultiscripts></mrow><mi>e</mi></math></span>

H. Akikawa; S. Ajimura; R. E. Chrien; P. M. Eugenio; G. B. Franklin; J. Franz; L. Gang; K. Imai; P. Khaustov; M. May; P. H. Pile; B. Quinn; A. Rusek; J. Sasao; R. I. Sawafta; H. Schmitt; H. Tamura; L. Tang; K. Tanida; L. Yuan; S. H. Zhou; L. H. Zhu; X. F. Zhu

doi:10.1103/PhysRevLett.88.082501

Hypernuclear Fine Structure in ${}_{Λ}^{9}B e$

H. Akikawa, S. Ajimura, R. E. Chrien, P. M. Eugenio, G. B. Franklin, J. Franz, L. Gang, K. Imai, P. Khaustov, M. May, P. H. Pile, B. Quinn, A. Rusek, J. Sasao, R. I. Sawafta, H. Schmitt, H. Tamura, L. Tang, K. Tanida, L. Yuan, S. H. Zhou, L. H. Zhu, and X. F. Zhu

Phys. Rev. Lett. 88, 082501 – Published 11 February 2002

Abstract

With a germanium detector array (Hyperball), we observed two $γ$ -ray peaks corresponding to the two transitions ( ${5 / 2}^{+} \to {1 / 2}^{+}$ and ${3 / 2}^{+} \to {1 / 2}^{+}$ ) in the $_{Λ}^{9} Be$ hypernucleus which was produced by the $^{9} Be (K^{-}, π^{-})$ reaction. The energies of the $γ$ rays are $3029 \pm 2 \pm 1 keV$ and $3060 \pm 2 \pm 1 keV$ . The energy difference was measured to be ${31.4}_{- 3.6}^{+ 2.5} keV$ , which indicates a very small $Λ$ -spin-dependent spin-orbit force between a $Λ$ and a nucleon. This is the smallest level splitting by far ever measured in a hypernucleus.

Received 6 November 2001

DOI:https://doi.org/10.1103/PhysRevLett.88.082501

Authors & Affiliations

H. Akikawa¹, S. Ajimura², R. E. Chrien³, P. M. Eugenio⁴, G. B. Franklin⁴, J. Franz⁵, L. Gang⁶, K. Imai¹, P. Khaustov⁴, M. May³, P. H. Pile³, B. Quinn⁴, A. Rusek³, J. Sasao⁷, R. I. Sawafta⁸, H. Schmitt⁵, H. Tamura⁷, L. Tang⁶, K. Tanida⁹, L. Yuan⁶, S. H. Zhou¹⁰, L. H. Zhu^1,10, and X. F. Zhu¹⁰

¹Department of Physics, Kyoto University, Kyoto 606-8502, Japan
²Department of Physics, Osaka University, Toyonaka 560-0043, Japan
³Brookhaven National Laboratory, Upton, New York 11973
⁴Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
⁵Department of Physics, University of Freiburg, Freiburg D-79104, Germany
⁶Department of Physics, Hampton University, Hampton, Virginia 23668
⁷Department of Physics, Tohoku University, Sendai 980-8578, Japan
⁸Physics Department, North Carolina A&T State University, Greensboro, North Carolina 27411
⁹Department of Physics, University of Tokyo, Tokyo 113-0033, Japan
¹⁰Department of Nuclear Physics, China Institute of Atomic Energy, Beijing 102413, China