Quark and Gluon Momentum Fractions in the Pion from N_{f}=2+1+1 Lattice QCD

• Published in: Physical review letters Vol. 127; no. 25; p. 252001
• Main Authors: Alexandrou, Constantia, Bacchio, Simone, Bergner, Georg, Finkenrath, Jacob, Gasbarro, Andrew, Hadjiyiannakou, Kyriakos, Jansen, Karl, Kostrzewa, Bartosz, Ottnad, Konstantin, Petschlies, Marcus, Pittler, Ferenc, Steffens, Fernanda, Urbach, Carsten, Wenger, Urs
• Format: Journal Article
• Language: English
• Published: United States 17-12-2021
• ISSN: 1079-7114
• DOI: 10.1103/PhysRevLett.127.252001

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 MS[over ¯] scheme at 2 GeV. We find ⟨x⟩_{u+d}=0.601(28), ⟨x⟩_{s}=0.059(13), ⟨x⟩_{c}=0.019(05), and ⟨x⟩_{g}=0.52(11) for the separate contributions, respectively, whose sum saturates the momentum sum rule.