Observation of χcJ (J = 0, 1, 2) → ppηη

Using (2712.4 ± 14.3) × 10⁶ ψ(3686) candidates collected by the BESIII detector operating at the BEPCII storage ring, the decays χcJ (J = 0, 1, 2) → ppηη are observed for the first time through the radiative transition ψ(3686) → γχcJ . The statistical significances forχcJ signals are all larger than 5σ. The branching fractions of χc0,1,2 → ppηη are determined to be (5.75 ± 0.59 ± 0.42) × 10⁻⁵, (1.40 ± 0.33 ± 0.17) × 10⁻⁵, and (2.64 ± 0.40 ± 0.27) × 10⁻⁵, respectively, where the first uncertainties are statistical and the second systematic. No evident resonant structures are found in the pp and pη/pη systems.