Abstract
A simple argument for the restoration of parity symmetry high in the hadron spectrum is presented. The restoration scale is estimated to be 2.5 GeV. This in turn implies that typical quark model phenomenology such as scalar confinement or the 3P0 decay model are only useful for low lying states. Minimal requirements for constructing more general phenomenologies are discussed. An additional mass degeneracy between J++ and J−− states is shown to occur and an isovector 3++ state is predicted at roughly 1700 MeV, in contradiction with the naive quark model. Similarly, isovector and isoscalar 4−− states are predicted at 2000 MeV. Finally, these results imply that Regge trajectories must become nonlinear at high spin.
Highlights
Spontaneous chiral symmetry breaking is one of the celebrated phenomena of low energy QCD
One expects this to be the case once the typical momentum transfers in hadronic bound states exceed the chiral symmetry breaking scale, p >> ΛχSB ≈ 1 GeV[1], since perturbative QCD knows nothing about vacuum structure
The central point is that the dominant manifestation of spontaneous chiral symmetry breaking high in the hadronic spectrum is in the quark field expansion and that the effective mass appearing in the quark field must approach zero as the average momentum probed by the quark gets large
Summary
A simple argument for the restoration of parity symmetry high in the hadron spectrum is presented. The restoration scale is estimated to be 2.5 GeV. This in turn implies that typical quark model phenomenology such as scalar confinement or the 3P0 decay model are only useful for low lying states. Minimal requirements for constructing more general phenomenologies are discussed. An additional mass degeneracy between J++ and J−− states is shown to occur and an isovector 3++ state is predicted at roughly 1700 MeV, in contradiction with the naive quark model. Isovector and isoscalar 4−− states are predicted at 2000 MeV. These results imply that Regge trajectories must become nonlinear at high spin
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