The Topological susceptibility and f(pi) from lattice QCD

We study the topological susceptibility, chi, in QCD with two quark flavours using the lattice field configurations recently produced by the UKQCD collaboration. We find clear evidence for the expected suppression at small quark mass, and examine the variation of chi with this mass. The resulting estimate of the pion decay constant, f_pi = 105 +/- 5 +18/-10 MeV, is consistent with the experimental value of approximately 93 MeV. We compare chi to the large-N_c prediction and find consistency over a large range of quark masses. The benefits of the non-perturbative action improvement scheme and the matched lattice spacings between simulation ensembles are discussed. We compare our results with other studies and suggest a reason why such a quark mass dependence has not been previously seen.

talk: Edinburgh 2000/04/11
fermion: lattice field theory
gauge field theory: SU(3)
flavor: 2
susceptibility: topological
symmetry: chiral
quark: mass
quark: sea
pi: decay constant
action: nonperturbative

References(21)

Figures(0)

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