Future gamma-ray spectroscopic experiment (J-PARC E63) on H 4 Λ

New gamma-ray spectroscopic experiments at the J-PARC K1.1 beam line are planned to study the charge symmetry breaking (CSB) effect in s-shell and p-shell mirror hypernuclei. For s-shell hypernuclei, a gamma-ray spectroscopy on HΛ4 (J- PARC E63) will be performed to measure the excitation energy Ex[ HΛ4(1+) ] with an expected accuracy of better than 5 keV, which is comparable to that of the recent measurement (J-PARC E13) of Ex[ HΛ4(1+) ]. Furthermore, we discuss the idea to study neutron rich mirror hypernuclei by the charge exchange (π−, K0) reaction and a new range counter system installed in the Hyperball-J, a Ge detector array.