Some results on excited hadrons in 2-flavor QCD

TL;DR

This paper presents hadron spectroscopy results in 2-flavor QCD using chirally improved quarks, analyzing various pion masses and lattice configurations to investigate scattering states and compare with quenched simulations.

Contribution

It provides new insights into excited hadron states in 2-flavor QCD with dynamical quarks and examines scattering state appearances across different ensembles.

Findings

Possible scattering states identified in scalar channel

Most channels do not show clear scattering state signals

Comparison with quenched results highlights dynamical effects

Abstract

Results of hadron spectroscopy with two dynamical mass-degenerate chirally improved quarks are presented. Three ensembles with pion masses of 322(5), 470(4) and 525(7) MeV, lattices of size 16^3 \times 32, and lattice spacings close to 0.15 fm are investigated. We discuss the possible appearance of scattering states, considering masses and eigenvectors. Partially quenched results in the scalar channel suggest the presence of a 2-particle state, however, in most channels we cannot identify them. Where available, we compare to results from quenched simulations using the same action.