Search for new hadronic decays of hc and observation of hc → pp¯ η

A search for the hadronic decays of the hc meson to the final states pp¯ π+π−π0, pp¯ η, and pp¯ π0 via the process ψ(3686) → π0hc is performed using (4.48 ± 0.03) × 108ψ(3686) events collected with the BESIII detector. The decay channel hc → pp¯ η is observed for the first time with a significance greater than 5σ and a branching fraction of (6.41 ± 1.74 ± 0.53 ± 1.00) × 10−4, where the uncertainties are statistical, systematic, and that from the branching fraction of ψ(3686) → π0hc. Strong evidence for the decay hc → pp¯ π+π−π0 is found with a significance of 4.9σ and a branching fraction of (3.84 ± 0.83 ± 0.69 ± 0.58) × 10−3. The significances include systematic uncertainties. No clear signal of the decay hc → pp¯ π0 is found, and an upper limit of 6.59 × 10−4 on its branching fraction is set at the 90% confidence level. [Figure not available: see fulltext.]