Meson spectroscopy with antineutrons

First results on meson spectroscopy using antineutrons as projectiles are reported. Three-body (pi+ pi+ pi-) and five-body (pi+ pi+ pi+ pi- pi-) final states following the annihilation of 100 to 290 MeV/c antineutrons on hydrogen were analyzed. The (pi+ pi-) invariant mass spectrum in the three-body reaction is accounted for by the rho-0 and f2(1270) resonances, together with an enhancement around 1540 MeV, in the region of the AX(1565) and the f2(1515) resonances, whereas the best fit for the (pi+ pi+ pi- pi-) invariant mass in five-body events shows the already reported structure zeta(1480) and suggests the presence of a second structure around 1650 MeV.