Speaker
Description
Transverse-momentum distributions inside hadrons have been a very active topic in hadron physics for the past three decades. An important ingredient to this endeavour is hadronization (or fragmentation), the formation of hadrons from partons. Belle was a pioneer in employing electron-positron annihilation data to constrain the Collins fragmentation function for charged pions and various other related fragmentation functions, providing data at a scale larger than that available at fixed-target lepton-scattering experiments. In this talk, among others, recent results on the transverse-momentum dependence of spin-averaged and transverse-spin dependent fragmentation will be discussed, including the first Belle measurement of the explicit transverse-momentum dependence of the pion and eta Collins fragmentation.
