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Shapes of the Proton

Gerald A. Miller
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Abstract

A model proton wave function, constructed using Poincare invariance, and constrained by recent electromagnetic form factor data, is used to study the shape of the proton. Spin-dependent quark densities are defined as matrix elements of density operators in proton states of definite spin-polarization, and shown to have an infinite variety of non-spherical shapes. For high momentum quarks with spin parallel to that of the proton, the shape resembles that of a peanut, but for quarks with anti-parallel spin the shape is that of a bagel.

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Gerald A. Miller. 2003-05-20. Shapes of the Proton. https://doi.org/10.1103/physrevc.68.022201

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