A hidden classical symmetry of QCD

Abstract

The classical part of the QCD partition function (the integrand) has, ignoring irrelevant exact zero modes of the Dirac operator, a local SU(2N_F) \supset SU(N_F)_L \times SU(N_F)_R \times U(1)_A symmetry which is absent at the Lagrangian level. This symmetry is broken anomalously and spontaneously. Effects of spontaneous breaking of chiral symmetry are contained in the near-zero modes of the Dirac operator. If physics of anomaly is also encoded in the same near-zero modes, then their truncation on the lattice should recover a hidden classical SU(2N_F) symmetry in correlators and spectra. This naturally explains observation on the lattice of a large degeneracy of hadrons, that is higher than the SU(N_F)_L \times SU(N_F)_R \times U(1)_A chiral symmetry, upon elimination by hands of the lowest-lying modes of the Dirac operator. We also discuss an implication of this symmetry for the high temperature QCD.

9 pp. Invited talk presented at (i) "Continuous advances in QCD", May 12 - May 15, 2016, University of Minnesota, USA (ii) 5th Int. Conf. on New Frontiers in Physics, 6-14 July, 2016, Crete, Greece. To be published in (ii) conference proceedings

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Cited by in corpus (4)

• Chiral Symmetry Breaking on the Lattice
• On $SU(2{)}_{CS}$-like groups and invariance of the fermionic action in QCD
• A chiralspin symmetry in QCD in Minkowski space-time
• Chiralspin symmetry and confinement