Speaker
Description
We present the first lattice-QCD calculation of the proton's twist-3 axial quark GPDs using the LaMET approach. The lattice computation is performed using one ensemble of $N_f=2+1+1$ maximally twisted mass fermions with a clover term at a single lattice spacing of 0.093 fm and a pion mass of 260 MeV, employing three proton boosts up to 1.67 GeV. The light-cone GPDs are defined in the symmetric frame, at $-t=0.69,1.38$ and $2.76$ GeV$^2$ and at zero skewness. We extract the leading combinations with twist-2 helicity GPDs, $\widetilde H+\widetilde G_2$ and $\widetilde E+\widetilde G_1$. We also isolate $\widetilde G_2$ and calculate the suppressed GPD $\widetilde G_4$, while $\widetilde G_3$ is confirmed to vanish at zero skewness. We also present several consistency checks, including the local limit of the twist-3 GPDs and the Burkhardt-Cottingham-type and Efremov-Teryaev-Leader-type sum rules.
