Phase Shift with LapH Propagators

TL;DR

This paper computes pion-pion scattering phase shifts using LapH propagators on dynamical lattices, demonstrating the efficacy of the stochastic LapH method for two-particle correlation functions and excited state energies.

Contribution

It introduces the use of LapH propagators combined with stochastic noise to accurately compute two-particle energies and phase shifts in lattice QCD.

Findings

Successful computation of isospin-2 phase shifts.

Effective use of stochastic LapH for t-to-t diagrams.

Demonstration of LapH method's efficacy in excited state extraction.

Abstract

The pion-pion scattering phase shift is computed using LapH propagators. The LapH method for computing quark propagators is used to form two-particle correlation functions with a number of different operators. Excited state energies of two-particle states on 2+1 dynamical, anisotropic lattices (Mpi=390 MeV) are computed to determine the phase shift in the isospin-2 channel. The signal for t-to-t diagrams for the isospin-0 channel are also presented to demonstrate the efficacy of the stochastic LapH method which combines LapH with diluted Z4 noise sources.