2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/223598A single-spin asymmetry was measured in the azimuthal distribution of pi+pi- pairs produced in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target. For the first time, evidence is found for a correlation between the transverse target polarization and the azimuthal orientation of the plane containing the two pions.The corresponding single-spin asymmetry is expected to be related to the product of the little-known quark transversity distribution function and an unknown naive-T-odd chiral-odd dihadron fragmentation function.18 pages, 4 figures, 1 table; minor revisions to content for clarityHigh Energy Physics - Experimenttext