A new method based on the concept of probability distribution is proposed to analyze the finite volume energy spectrum in lattice QCD. Using synthetic lattice data, we demonstrate that for the channel with quantum numbers of the Delta-resonance a cle
ar resonance structure emerges in such an analysis. Consequently, measuring the volume-dependence of the energy levels in lattice QCD will allow to determine the mass and the width of the Delta with reasonable accuracy.
We reanalyse the topological susceptibility assuming the possibility of a significant paramagnetic suppression of the three-flavour quark condensate and a correlated enhancement of vacuum fluctuations of $sbar{s}$ pairs. Using the framework of resumm
ed ChPT, we point out that simulations performed near the physical point, with a significant mass hierarchy between u,d and s dynamical quarks, are not able to disentangle the contributions from the quark condensate and sea $sbar{s}$-pair fluctuations, and that simulations with three light quark masses of the same order are better suited for this purpose. We perform a combined fit of recent RBC/UKQCD data on pseudoscalar masses and decay constants as well as the topological susceptibility, and we reconsider the determination of lattice spacings in our framework, working out the consequences on the parameters of the chiral Lagrangian. We obtain Sigma(3;2 GeV)^1/3=243 pm 12 MeV for the three-flavour quark condensate in the chiral limit. We notice a significant suppression compared to the two-flavour quark condensate Sigma(2;2 GeV)/Sigma(3;2 GeV)=1.51pm 0.11 and we confirm previous findings of a competition between leading order and next-to-leading order contributions in three-flavour chiral series.
