Antiquark asymmetry
DOI: 10.1063/PT.3.5149
It was interesting to read the item by Johanna Miller (Physics Today, May 2021, page 14
But I feel that it is necessary to add a little to the incomplete discussion of the history of that asymmetry discovery. Using the cloudy bag model, which successfully incorporates chiral symmetry into the MIT bag model, I predicted the asymmetry 1 in 1983, almost a decade before the violation of the Gottfried sum rule was experimentally confirmed. 2
The mechanism is the dominance of the π+–neutron configuration when the proton emits a pion. The pion contribution to deep inelastic scattering was first mentioned by J. D. Sullivan and Richard Feynman and is often referred to as the Sullivan process. In 1983, however, almost no one in the high-energy-physics community took the idea of a contribution from the pion cloud seriously, as deep inelastic scattering was such a short-distance phenomenon; the constraints of chiral symmetry there were not understood. Certainly no one else, including Sullivan, had discussed the process as a source of flavor asymmetry.
In a November 2021 letter
References
1. A. W. Thomas, Phys. Lett. B 126, 97 (1983). https://doi.org/10.1016/0370-2693(83)90026-6
2. P. Amaudruz et al. (New Muon collaboration), Phys. Rev. Lett. 66, 2712 (1991). https://doi.org/10.1103/PhysRevLett.66.2712
3. J. J. Ethier et al., Phys. Rev. D 100, 034014 (2019). https://doi.org/10.1103/PhysRevD.100.034014
More about the Authors
Anthony W. Thomas. University of Adelaide, Adelaide, Australia.