Observation of spin-dependent charge symmetry breaking in
interaction;
-ray spectroscopy of
He
Yamamoto, T. O.*; Hasegawa, Shoichi
; Hayakawa, Shuhei; Hosomi, Kenji
; Hwang, S.; Ichikawa, Yudai
; Imai, Kenichi; Kimbara, Shinji; Nakada, Yoshiyuki; Sako, Hiroyuki
; Sato, Susumu
; Sugimura, Hitoshi; Tanida, Kiyoshi
; J-PARC E13 Collaboration*; 41 of others*
The energy spacing between the spin-doublet bound state of
He
was determined to be
keV, by measuring
rays for the
transition with a high efficiency germanium detector array in coincidence with the
He reaction at J-PARC. In comparison to the corresponding energy spacing in the mirror hypernucleus
H, the present result clearly indicates the existence of charge symmetry breaking (CSB) in
interaction. By combining the energy spacings with the known ground-state binding energies, it is also found that the CSB effect is large in the
ground state but is vanishingly small in the
excited state, demonstrating that the
CSB interaction has spin dependence.