Relatore: Dr Rajan Gupta - Los Alamos National Laboratory (NM, USA)Esperto di studi non-perturbativi del settore del modello standard soggetto alla interazione forteLuogo: sala FeynmanE-mail di riferimento: francesco.direnzo@unipr.it Abstract: The remarkable result, from the measurements of spin asymmetry in polarizeddeep inelastic scattering by the EMC collaboration, that the sum of thespins of the quarks contributes less than half of the total spin of theproton lay down the challenge to explain this “proton spin crisis” fromQCD. I will show that calculations of the required matrix elements usingLattice QCD are now in a position to provide first principle results withall systematics under control and the steady reduction in the error budget.The most well determined of the contributions is of the quark's intrinsicspin. Existing lattice results will be reviewed and compared with currentphenomenological/experimental estimates. PDF Locandina