出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We determine the mass of the lightest ¯ qq scalar meson with I = 1 using the simulation with two
dynamical Domain Wall Fermions. The conventional exponential fit of the scalar correlator is
justified in this case giving the mass 1.58±0.34 GeV. In general the scalar correlator receives
also the bubble contribution, which is the intermediate state with two pseudoscalar mesons. This
contribution is sizable at light quark masses and has to be incorporated in the fit of the scalar
correlator in order to extract the scalar meson mass. We provide predictions for the bubble contribution
in Partially Quenched ChPT, Staggered ChPT and ChPT for Mixed quark actions. We
find that the bubble contribution is significantly affected by the unphysical approximations that
are employed in simulations. It can render the negative sign and unphysical effective mass 2Mp
in the scalar correlator with I = 1.
