Hadron spectrum of QCD with one quark flavor

TL;DR

This study investigates the hadron spectrum of one-flavor QCD using lattice simulations and chiral perturbation theory, providing insights into the properties of this simplified version of quantum chromodynamics.

Contribution

It presents the first detailed lattice study of one-flavor QCD's hadron spectrum, employing improved actions and partially quenched chiral perturbation theory for analysis.

Findings

Mass spectrum of hadronic states at two lattice spacings

Analysis of pion properties with PQChPT

Observation of symmetry enhancement with valence quarks

Abstract

The hadron spectrum of one flavor QCD is studied by Monte Carlo simulations. The Symanzik tree-level-improved Wilson action is used for the gauge field and the Wilson action for the fermion. The theory is simulated by a polynomial hybrid Monte Carlo algorithm (PHMC). The mass spectrum of hadronic bound states is investigated at two different lattice spacings: a ~ 0.37r_0 and a ~ 0.27r_0, corresponding to ~0.19fm and ~0.13fm in ordinary QCD. The lattice extension is fixed to L ~ 4.4r_0 (~2.2fm). The lightest simulated quark mass corresponds to a pion with mass ~270MeV. Properties of the theory are analyzed by making use of the ideas of partially quenched chiral perturbation theory (PQChPT). The symmetry of the single flavor theory can be artificially enhanced by adding extra valence quarks, which can be interpreted as u and d quarks. Operators in the valence pion sector can be built. Masses and decay constants are analyzed by using PQChPT formulae at next-to-leading order.