First determination of the level structure of an
-shell hypernucleus,
F
Yang, S. B.*; Ekawa, Hiroyuki; Hasegawa, Shoichi
; Hayakawa, Shuhei; Hosomi, Kenji
; Ichikawa, Yudai
; Imai, Kenichi; Sako, Hiroyuki
; Sato, Susumu
; Tanida, Kiyoshi
; Sugimura, Hitoshi; J-PARC E13 Collaboration*; 37 of others*
We report on the first observation of
rays emitted from an
-shell hypernucleus,
F. The energy spacing between the ground state doublet,
and
states, of
F is determined to be
keV by measuring the
-ray energy of the
transition. In addition, three
-ray peaks are observed and assigned as
,
, and
transitions. The excitation energies of the
and
states are determined to be
keV and
keV, respectively. It is found that the ground state doublet spacing is well described by theoretical models based on existing
- and
-shell hypernuclear data.