Quark and gluon momentum fractions in the pion from $N_f=2+1+1$ lattice QCD (2109.10692v1)

Abstract: We perform the first full decomposition of the pion momentum into its gluon and quark contributions. We employ an ensemble generated by the Extended Twisted Mass Collaboration with $N_f=2 + 1 +1$ Wilson twisted mass clover fermions at maximal twist tuned to reproduce the physical pion mass. We present our results in the $\overline{\mathrm{MS}}$ scheme at $2\gev$. We find $\avgx_{u+d}=0.601(28)$, $\avgx_s=0.059(13)$, $\avgx_c=0.019(05)$, and $\avgx_g=0.52(11)$ for the separate contributions, respectively, whose sum saturates the momentum sum rule.