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arXiv · 2109.10692

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

Constantia Alexandrou·Simone Bacchio·Georg Bergner·Jacob Finkenrath·Andrew Gasbarro·Kyriakos Hadjiyiannakou·Karl Jansen·Bartosz Kostrzewa·Konstantin Ottnad·Marcus Petschlies·Ferenc Pittler·Fernanda Steffens·Carsten Urbach·Urs Wenger
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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.

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Constantia Alexandrou, Simone Bacchio, Georg Bergner, Jacob Finkenrath, Andrew Gasbarro, Kyriakos Hadjiyiannakou, Karl Jansen, Bartosz Kostrzewa, Konstantin Ottnad, Marcus Petschlies, Ferenc Pittler, Fernanda Steffens, Carsten Urbach, Urs Wenger. 2021-09-22. Quark and gluon momentum fractions in the pion from $N_f=2+1+1$ lattice QCD. https://doi.org/10.1103/physrevlett.127.252001

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