Based on
(2712.4±14.3)×106 ψ(3686) events, we investigate four hadronic decay modes of the
P-wave charmonium spin-singlet state
hc(1P1)→h+h−π0/η (
h=π or
K) via the process
ψ(3686)→π0hc at BESIII. The
hc→π+π−π0 decay is observed with a significance of
9.6σ after taking into account systematic uncertainties. Evidences for
hc→K+K−π0 and
hc→K+K−η are found with significances of
3.5σ and
3.3σ, respectively, after considering the systematic uncertainties. The branching fractions of these decays are measured to be
B(hc→π+π−π0)=(1.36±0.16±0.14)×10−3,
B(hc→K+K−π0)=(3.26±0.84±0.36)×10−4, and
B(hc→K+K−η)=(3.13±1.08±0.38)×10−4, where the first uncertainties are statistical and the second are systematic. No significant signal of
hc→π+π−η is found, and the upper limit of its decay branching fraction is determined to be
B(hc→π+π−η)<4.0×10−4 at the 90% confidence level. Published by the American Physical Society 2024