ISSN - 00319007, EISSN - 10797114, Physical Review Letters, 2011, vol. 107, p. -
Observation of transverse polarization asymmetries of charged pion pairs in e +e - annihilation near √s=10.58GeV
The interference fragmentation function translates the fragmentation of a quark with a transverse projection of the spin into an azimuthal asymmetry of two final-state hadrons. In e +e - annihilation the product of two interference fragmentation functions is measured. We report nonzero asymmetries for pairs of charge-ordered π +π - pairs, which indicate a significant interference fragmentation function in this channel. The results are obtained from a 672fb -1 data sample that contains 711×106 π +π - pairs and was collected at and near the Υ(4S) resonance, with the Belle detector at the KEKB asymmetric-energy e +e - collider. © 2011 American Physical Society.