Twist-three relations of gluonic correlators for the transversely   polarized nucleon
  We derive exact relations among the polarized gluon and three-gluon distributions in the transversely polarized nucleon which are relevant to single and double spin asymmetries in various hard processes. We also discuss the partonic decomposition of the transverse nucleon spin and point out a potential problem with frame-independence. 
Yoshitaka Hatta, Kazuhiro Tanaka, Shinsuke Yoshida
hep-ph