1 research outputs found
Effective chiral restoration in the hadronic spectrum and QCD
Effective chiral restoration in the hadronic spectrum has been conjectured as
an explanation of multiplets of nearly degenerate seen in highly excited
hadrons. The conjecture depends on the states being insensitive to the dynamics
of spontaneous chiral symmetry breaking. A key question is whether this concept
is well defined in QCD. This paper shows that it is by means of an explicit
formal construction. This construction allows one to characterize this
sensitivity for any observable calculable in QCD in Euclidean space via a
functional integral. The construction depends on a generalization of the
Banks-Casher theorem. It exploits the fact that {\it all} dynamics sensitive to
spontaneous chiral symmetry breaking observables in correlation functions arise
from fermion modes of zero virtuality (in the infinite volume limit), while
such modes make {\it no} contribution to any of the dynamics which preserves
chiral symmetry. In principle this construction can be implemented in lattice
QCD. The prospect of a practical lattice implementation yielding a direct
numerical test of the concept of effective chiral restoration is discussed