Observation of Spin-Dependent Charge Symmetry Breaking in $\Lambda N$ Interaction: Gamma-Ray Spectroscopy of ${}_{\Lambda }^4$He

T. O. Yamamoto, M. Agnello, Y. Akazawa +51

The energy spacing between the ground-state spin doublet of ${}_{\Lambda }^4$He(1${}^{+}$,0${}^{+}$) was determined to be $1406\pm 2\pm 2$ keV, by measuring $\gamma$ rays for the $1^{+}\to 0^{+}$ transitio…