Observation of the decays χcJ → nK S 0 Λ ¯ $$ {\mathrm{nK}}_{\mathrm{S}}^0\overline{\Lambda} $$ + c.c.

By analyzing 4.48 × 108 ψ(3686) events collected with the BESIII detector, we observe the decays χcJ → $$ {nK}_S^0\overline{\Lambda} $$ + c.c. (J = 0, 1, 2) for the first time, via the radiative transition ψ(3686) → γχcJ. The branching fractions are determined to be (6.65 ± 0.26stat ± 0.41syst) × 10−4, (1.66 ± 0.12stat ± 0.12syst) × 10−4, and (3.58 ± 0.16stat ± 0.23syst) × 10−4 for J = 0, 1, and 2, respectively.