Proton mass decompositions in the NNLO QCD

Fuente: arXiv
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Main Author: Tanaka, Kazuhiro
Format: Preprint
Published: 2025
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author Tanaka, Kazuhiro
author_facet Tanaka, Kazuhiro
contents Proton matrix elements of the QCD energy-momentum tensor (EMT) are expressed by the gravitational form factors. The forward values of the gravitational form factors allow for a decomposition of the proton mass into contributions from quarks and gluons, and further subdivisions into contributions from quark masses and from the QCD trace anomaly may be considered. We present the most recent evaluations of these mass decompositions, using a recent quantitative evaluation of the forward values of relevant gravitational form factors at the next-to-next-to-leading order (NNLO) QCD. We also calculate the renormalization scale dependence of each component within these decompositions. Furthermore, similar calculations are performed with another decomposition of the proton mass, organized strictly according to the separation into the traceless part and trace part for each of the gauge-invariant quark/gluon parts of the EMT, such that the former (twist-two) quark/gluon contributions of the EMT embody the effects of the partonic motions inside the proton, while the latter (twist-four) contributions are induced as parton correlations by non-perturbative QCD interactions. We demonstrate the advantages of this new decomposition. We also present the results for the pion, which exhibit quite different parton-correlation behaviors from the proton.
format Preprint
id arxiv_https___arxiv_org_abs_2511_18310
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Proton mass decompositions in the NNLO QCD
Tanaka, Kazuhiro
High Energy Physics - Phenomenology
High Energy Physics - Experiment
High Energy Physics - Lattice
Nuclear Experiment
Nuclear Theory
Proton matrix elements of the QCD energy-momentum tensor (EMT) are expressed by the gravitational form factors. The forward values of the gravitational form factors allow for a decomposition of the proton mass into contributions from quarks and gluons, and further subdivisions into contributions from quark masses and from the QCD trace anomaly may be considered. We present the most recent evaluations of these mass decompositions, using a recent quantitative evaluation of the forward values of relevant gravitational form factors at the next-to-next-to-leading order (NNLO) QCD. We also calculate the renormalization scale dependence of each component within these decompositions. Furthermore, similar calculations are performed with another decomposition of the proton mass, organized strictly according to the separation into the traceless part and trace part for each of the gauge-invariant quark/gluon parts of the EMT, such that the former (twist-two) quark/gluon contributions of the EMT embody the effects of the partonic motions inside the proton, while the latter (twist-four) contributions are induced as parton correlations by non-perturbative QCD interactions. We demonstrate the advantages of this new decomposition. We also present the results for the pion, which exhibit quite different parton-correlation behaviors from the proton.
title Proton mass decompositions in the NNLO QCD
topic High Energy Physics - Phenomenology
High Energy Physics - Experiment
High Energy Physics - Lattice
Nuclear Experiment
Nuclear Theory
url https://arxiv.org/abs/2511.18310