How far can you go ? Surprises and pitfalls in three-flavour chiral extrapolations
Abstract
The presence of strange sea quark pairs may have a significant impact of the pattern of chiral symmetry breaking : in particular large differences can occur between the chiral limits of two and three massless flavours (i.e., whether ms is kept at its physical value or sent to zero). We recall some indications of such a scenario in QCD, in relation with the peculiar dynamics of the scalar sector. We explain how this could affect the convergence of three-flavour chiral series, commonly used to extrapolate the results of lattice simulations. Finally, we indicate how lattice simulations with three dynamical flavours could unveil such an effect through the quark-mass dependence of light meson masses and decay constants.
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