First Measurement of the Interference Fragmentation Function in e^+e^- at Belle

A first measurement of the di-hadron interference fragmentation function of light quarks in pion pairs with the Belle detector is presented. The chiral odd nature of this fragmentation function allows the use as a quark polarimeter sensitive to the transverse polarization of the fragmenting quark. Therefore it can be used together with data taken at fixed target and collider experiments to extract the quark transversity distribution. A sample consisting of $711 \times 10^6$ di-hadron pairs was extracted from 661 $fb^{-1}$ of data recorded near the $\Upsilon(4S)$ resonance delivered by the KEKB $e^+$$e^{-}$ collider.