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Title: The pressure distribution inside the proton

Abstract

Here, the proton, one of the components of atomic nuclei, is composed of fundamental particles called quarks and gluons. Gluons are the carriers of the force that binds quarks together, and free quarks are never found in isolation—that is, they are confined within the composite particles in which they reside. The origin of quark confinement is one of the most important questions in modern particle and nuclear physics because confinement is at the core of what makes the proton a stable particle and thus provides stability to the Universe. The internal quark structure of the proton is revealed by deeply virtual Compton scattering, a process in which electrons are scattered off quarks inside the protons, which subsequently emit high-energy photons, which are detected in coincidence with the scattered electrons and recoil protons. Here we report a measurement of the pressure distribution experienced by the quarks in the proton. We find a strong repulsive pressure near the centre of the proton (up to 0.6 femtometres) and a binding pressure at greater distances. The average peak pressure near the centre is about 1035 pascals, which exceeds the pressure estimated for the most densely packed known objects in the Universe, neutron stars. Thismore » work opens up a new area of research on the fundamental gravitational properties of protons, neutrons and nuclei, which can provide access to their physical radii, the internal shear forces acting on the quarks and their pressure distributions.« less

Authors:
 [1];  [1];  [1]
  1. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
OSTI Identifier:
1438388
Report Number(s):
JLAB-PHY-17-2536; DOE/OR/23177-4198
Journal ID: ISSN 0028-0836; PII: 60; TRN: US1900430
Grant/Contract Number:  
AC05-06OR23177
Resource Type:
Accepted Manuscript
Journal Name:
Nature (London)
Additional Journal Information:
Journal Name: Nature (London); Journal Volume: 557; Journal Issue: 7705; Journal ID: ISSN 0028-0836
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS

Citation Formats

Burkert, V. D., Elouadrhiri, L., and Girod, F. X. The pressure distribution inside the proton. United States: N. p., 2018. Web. doi:10.1038/s41586-018-0060-z.
Burkert, V. D., Elouadrhiri, L., & Girod, F. X. The pressure distribution inside the proton. United States. doi:10.1038/s41586-018-0060-z.
Burkert, V. D., Elouadrhiri, L., and Girod, F. X. Wed . "The pressure distribution inside the proton". United States. doi:10.1038/s41586-018-0060-z. https://www.osti.gov/servlets/purl/1438388.
@article{osti_1438388,
title = {The pressure distribution inside the proton},
author = {Burkert, V. D. and Elouadrhiri, L. and Girod, F. X.},
abstractNote = {Here, the proton, one of the components of atomic nuclei, is composed of fundamental particles called quarks and gluons. Gluons are the carriers of the force that binds quarks together, and free quarks are never found in isolation—that is, they are confined within the composite particles in which they reside. The origin of quark confinement is one of the most important questions in modern particle and nuclear physics because confinement is at the core of what makes the proton a stable particle and thus provides stability to the Universe. The internal quark structure of the proton is revealed by deeply virtual Compton scattering, a process in which electrons are scattered off quarks inside the protons, which subsequently emit high-energy photons, which are detected in coincidence with the scattered electrons and recoil protons. Here we report a measurement of the pressure distribution experienced by the quarks in the proton. We find a strong repulsive pressure near the centre of the proton (up to 0.6 femtometres) and a binding pressure at greater distances. The average peak pressure near the centre is about 1035 pascals, which exceeds the pressure estimated for the most densely packed known objects in the Universe, neutron stars. This work opens up a new area of research on the fundamental gravitational properties of protons, neutrons and nuclei, which can provide access to their physical radii, the internal shear forces acting on the quarks and their pressure distributions.},
doi = {10.1038/s41586-018-0060-z},
journal = {Nature (London)},
number = 7705,
volume = 557,
place = {United States},
year = {2018},
month = {5}
}

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Free Publicly Available Full Text
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Cited by: 28 works
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Figures / Tables:

FIG. 1 FIG. 1: The radial pressure distribution in the proton. The graph shows the pressure distribution r2p(r) resulting from the interactions of the quarks in the proton versus the radial distance from the center in femtometer. The black central line corresponds to the pressure extracted from the D-term parameters fitted tomore » the published data at 6 GeV [10, 11]. The corresponding estimated uncertainties are displayed as the shaded area shown in light green. They correspond to 1 standard deviation. See text for more details.« less

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    Works referencing / citing this record:

    Off-shell quark bilinear operator Green’s functions at two loops
    journal, June 2019


    Proton internal pressure in pp and p̄p elastic scattering
    journal, April 2019


    Estimation of Nucleon D-Term in QCD
    journal, June 2019


    Off-shell quark bilinear operator Green’s functions at two loops
    journal, June 2019


    Proton internal pressure in pp and p̄p elastic scattering
    journal, April 2019


    Estimation of Nucleon D-Term in QCD
    journal, June 2019


      Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.