Summarizing SIDIS

• Transverse momenta of partons become relevant, effects appearing in azimuthal asymmetries

• DF’s and FF’s depend on two variables,

• (x,pT) and (z,kT)

• Fragmentation functions are not constrained by time-reversal invariance

• This allows T-odd functions H1 and D1T, appearing in single spin asymmetries

Notes: