Measurement of Azimuthal Asymmetries in Inclusive Production of Hadron Pairs in e + e Annihilation at √ s = 10.58 GeV

The Collins effect connects transverse quark spin with a measurable azimuthal asymmetry in the yield of hadronic fragments around the quark's momentum vector. Using two different reconstruction methods we measure statistically significant azimuthal asymmetries for charged pion pairs in e+e- annihilation at center-of-mass energies of 10.52 GeV and 10.58 GeV, which can be attributed to the fragmentation of primordial quarks with transverse spin components. The measurement was performed using a data set of 547fb-1 collected by the Belle detector at KEKB improving the statistics of the previously published results by nearly a factor of 20. © 2008 The American Physical Society.