Speaker
Description
Inclusive hadron production cross sections and angular distributions in e+e− collisions shed light on fundamental questions of hadronization and fragmentation processes. We present measurements of the Collins azimuthal asymmetries in inclusive production of hadron pairs, in the e+e− → h1h2X annihilation process, where the hadrons h1,2 (either kaons or pions) are produced in opposite hemispheres. The data collected by the BABAR detector allow the determination of the Collins fragmentation function dependence on hadron fractional energy and transverse momentum for the up, down and, for the first time, strange quarks. These data can be combined with semi-inclusive deep-inelastic-scattering data to extract the transversity distribution function, which is the least known leading-twist component of the QCD description of the partonic structure of the nucleon.
