Observation of χcJ →p p ¯ KS0 K-π++ c. c.

By analyzing (27.12±0.14)×108 ψ(3686) events collected with the BESIII detector operating at the BEPCII collider, the decays χcJ→pp¯KS0K-π++c.c. (J=0,1,2) are observed for the first time with statistical significances greater than 10σ. The branching fractions of these decays are determined to be B(χc0→pp¯KS0K-π++c.c.)=(2.61±0.27±0.32)×10-5, B(χc1→pp¯KS0K-π++c.c.)=(4.16±0.24±0.46)×10-5, and B(χc2→pp¯KS0K-π++c.c.)=(5.63±0.28±0.46)×10-5, respectively. The processes χc1,2→p¯Λ(1520)KS0π++c.c. are also observed, with statistical significances of 5.7σ and 7.0σ, respectively. Evidence for χc0→p¯Λ(1520)KS0π++c.c. is found with statistical significances of 3.3σ. The corresponding branching fractions are determined to be B(χc0→p¯Λ(1520)KS0π++c.c.)=(1.61-0.64+0.68±0.23)×10-5, B(χc1→p¯Λ(1520)KS0π++c.c.)=(4.06-0.76+0.80±0.52)×10-5, and B(χc2→p¯Λ(1520)KS0π++c.c.)=(4.09-0.84+0.87±0.42)×10-5. Here, the first uncertainties are statistical and the second ones are systematic.