eta pi(+)pi(-) Resonant Structure around 1.8 GeV/c(2) and eta(1405) in J/psi -> omega eta pi(+)pi(-)

We present results of a study of the decay J/psi -> omega eta pi(+)pi(-) using a sample of (225.2 +/- 2.8) x 10(6) J/psi events collected by the BESIII detector, and report the observation of a new process J/psi -> omega X(1870) with a statistical significance of 7.2 sigma, in which X(1870) decays to a(0)(+/-)(980)pi(-/+). Fitting to eta pi(+)pi(-) mass spectrum yields a mass M = 1877.3 +/- 6.3(stat)(-7.4)(+3.4)(syst) MeV/c(2), a width Gamma = 57 +/- 12(stat)(-4)(+19)(syst) MeV/c(2), and a product branching fraction B(J/psi -> omega X) x B(X -> a(0)(+/-)(980)pi(-/+)) x B(a(0)(+/-)(980)(->) eta pi(+/-)) = [1.50 +/- 0.26(stat)(-0.36)(+0.72)(syst)] x 10(-4). Signals for J/psi -> omega f(1)(1285) and J/psi -> omega eta(1405) are also clearly observed and measured.