$\rho$ Meson Decay in 2+1 Flavor Lattice QCD

TL;DR

This study uses lattice QCD simulations with 2+1 flavors to analyze the $ ho$ meson decay, estimating resonance parameters from scattering phase shifts at different quark masses.

Contribution

It provides new lattice QCD calculations of $ ho$ meson decay parameters with 2+1 flavors, improving understanding of resonance behavior at near-physical quark masses.

Findings

Resonance mass and coupling constants estimated from phase shifts.

Comparison with previous 2-flavor results and experimental data.

Analysis at two different pion masses to study quark mass dependence.

Abstract

We perform a lattice QCD study of the $\rho$ meson decay from the $N_f=2+1$ full QCD configurations generated with a renormalization group improved gauge action and a non-perturbatively $O(a)$-improved Wilson fermion action. The resonance parameters, the effective $\rho\to\pi\pi$ coupling constant and the resonance mass, are estimated from the $P$-wave scattering phase shift for the isospin I=1 two-pion system. The finite size formulas are employed to calculate the phase shift from the energy on the lattice. Our calculations are carried out at two quark masses, $m_\pi=410\,{\rm MeV}$ ($m_\pi/m_\rho=0.46$) and $m_\pi=300\,{\rm MeV}$ ($m_\pi/m_\rho=0.35$), on a $32^3\times 64$ ($La=2.9\,{\rm fm}$) lattice at the lattice spacing $a=0.091\,{\rm fm}$. We compare our results at these two quark masses with those given in the previous works using $N_f=2$ full QCD configurations and the experiment.