“Proton Spin Crisis”
Successful Description of Baryon mM by Quark Model
”quark carries all proton spin”
Puzzling Data from polarized lepton-Nucleon scattering
DS : total quark spin contribution to the proton spin
Ds: strange quark contribution to the proton spin
Fixes for ”Spin Crisis”
- Gluon is polarized : DG > 0
- Anti-quark is polarized: indirect decomposition suggests Dsɘ
- Steeper small-x