Low Energy Chiral Lagrangian Parameters for Scalar and Pseudoscalar Mesons

TL;DR

This study investigates scalar and pseudoscalar mesons in quenched QCD using improved Wilson fermions, analyzing chiral behavior, meson masses, decay constants, and the eta prime mass to understand quenched chiral logs and scalar meson properties.

Contribution

It provides high-statistics lattice results for meson propagators, estimates quenched chiral log effects, and determines the scalar meson mass after removing quenched artifacts.

Findings

Determined pseudoscalar masses and decay constants as functions of quark mass.

Estimated quenched chiral log parameter delta and its effects.

Measured the eta prime mass insertion and scalar meson mass after QCL removal.

Abstract

We present results of a high-statistics study of scalar and pseudoscalar meson propagators in quenched QCD at two values of lattice spacing, beta = 5.7 and 5.9, with clover-improved Wilson fermions. The study of the chiral limit is facilitated by the pole-shifting ansatz of the modified quenched approximation. Pseudoscalar masses and decay constants are determined as a function of quark mass and quenched chiral log effects are estimated. A study of the flavor singlet eta prime hairpin diagram yields a precise determination of the eta prime mass insertion. The corresponding value of the quenched chiral log parameter delta is compared with the observed QCL effects. Removal of QCL effects from the scalar propagator allows a determination of the mass of the lowest lying isovector scalar $q\bar{q}$ meson.