The topological susceptibility and pion decay constant from lattice QCD

TL;DR

This paper investigates the topological susceptibility and pion decay constant in two-flavor lattice QCD, confirming theoretical predictions and providing estimates consistent with experimental values.

Contribution

It presents the first lattice QCD calculation of topological susceptibility and pion decay constant with results aligning with theoretical and experimental expectations.

Findings

Topological susceptibility is suppressed at small quark masses.

Estimated pion decay constant is 105 +/-5 +18/-10 MeV.

Results are consistent with large-N_c predictions.

Abstract

We study the topological susceptibility, chi, in two flavour lattice QCD. We find clear evidence for the expected suppression of chi at small quark mass. The 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.