We explore the decay properties of the isovector and isoscalar 1−+ light hybrids, π1 and η1, in Nf = 2 lattice QCD at a pion mass mπ ≈ 417 MeV. The McNeile and Michael method is adopted to extract the effective couplings for individual decay modes, which are used to estimate the partial decay widths of π1(1600) and η1(1855) by assuming SU(3) symmetry. The partial decay widths of π1(1600) are predicted to be \((\Gamma_{b1\pi}, \Gamma_{f1(1285)\pi}, \Gamma_{\rho \pi}, \Gamma_{K* \bar{K}})=(325\pm75, \mathcal{O}(10),52\pm7,8.6\pm1.3)\) MeV, and the total width is estimated to be 396 ± 90 MeV, considering only statistical errors. If η1(1855) and the 4.4σ signal observed by BESIII (labeled as η1(2200)) are taken as the two mass eigenstates of the isoscalar 1−+ light hybrids in SU(3), then the dominant decay channel(s) of η1(1855) (η1(2200)) is \(K_{1}(1270)\bar{K}\ (K_{1}(1270)\bar{K}\) and \(K_{1}(1400)\bar{K}\) through the 1+(−)0−(+) mode. The vector-vector decay modes are also significant for the two η1 states. Using the mixing angle α ≈ 22.7° obtained from lattice QCD for the two η1 states, the total widths are estimated to be \(\Gamma_{\eta1(1855)} = 282(85)\) MeV and \(\Gamma_{\eta1(2200)} = 455(143)\) MeV. The former is compatible with the experimental width of η1(1855). Although many systematic uncertainties are not well controlled, these results are qualitatively informative for the experimental search for light hybrids.
