Rl. Jaffe et al., INTERFERENCE FRAGMENTATION FUNCTIONS AND VALENCE QUARK SPIN DISTRIBUTIONS IN THE NUCLEON, Physical review. D. Particles and fields, 57(9), 1998, pp. 5920-5922
We explore further applications of the twist-two quark interference fr
agmentation functions introduced earlier. We show that semi-inclusive
production of two pions in the current fragmentation region in deep in
elastic scattering of a longitudinally polarized electron on a longitu
dinally polarized nucleon can provide a probe of the valence quark spi
n (or helicity difference) distribution in the nucleon.