Decomposition of the proton spin from lattice QCD

The gluon and quark contributions to the proton spin are computed using an ensemble of gauge configurations with twisted mass Wilson fermions with masses tuned to approximately reproduce their physical values. A non-perturbative renormalization is carried out for both quark and gluon matrix elements. The contribution of up, down, strange and charm quarks to the proton intrinsic spin, orbital angular momentum and angular momentum are determined. All scale and scheme dependent quantities are given in the $\mathrm{ \overline{MS}}$ scheme at 2~GeV