ρmeson decay in2+1flavor lattice QCD

Abstract

We perform a lattice QCD study of the meson decay from the N f ¼ 2 þ 1 full QCD configurations generated with a renormalization group improved gauge action and a nonperturbatively OðaÞ-improved Wilson fermion action. The resonance parameters, the effective ! coupling constant and the resonance mass, are estimated from the P-wave scattering phase shift for the isospin I ¼ 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 ¼ 410 MeV (m =m ¼ 0:46) and m ¼ 300 MeV (m =m ¼ 0:35), on a 32 3 Â 64 (La ¼ 2:9 fm) lattice at the lattice spacing a ¼ 0:091 fm. We compare our results at these two quark masses with those given in the previous works using N f ¼ 2 full QCD configurations and the experiment.

Masses and decay constants of the Ds0*(2317) and DBali1, Collins2, Cox3 et al. 2017Phys. Rev. D105131611View full textAdd to dashboardCite

“…The quark line diagrams were evaluated following the stochastic approach of Refs. [65][66][67]. The limited basis of interpolators required means this approach is substantially cheaper in terms of the computer time compared to other methods such as the distillation technique [109,110] and enables large volumes and small pion masses to be realised.…”

“…These quark line diagrams are evaluated using spin and colour diluted complex Z 2 stochastic sources with the one-end trick [63,64], following Refs. [65][66][67]. Evaluation of the DK → DK box diagram requires two sequential propagators involving a combination of light and charm (lc) quarks and strange and light quarks (sl), represented by the thin and thick lines with open arrows in the bottom right of Fig.…”

An $a_0$ resonance in strongly coupled $\pi \eta$, $K \overline{K}$ scattering from lattice QCD

“…The simple case of elastic ππ scattering in P -wave, where the narrow ρ resonance appears, has been considered extensively in lattice QCD calculations [40][41][42][43][44][45][46][47], and recently the first extraction of a coupled-channel S-matrix from QCD was reported [48,49], for the case of πK, ηK scattering in S, P and D-waves. This calculation, performed at a larger than physical light-quark mass, demonstrated that resonance properties can be extracted from such calculations, albeit in a case where the two channels prove to be relatively weakly coupled.…”

Meson resonances on the lattice

“…This channel has been considered in several recent lattice calculations [21,22,23,24,25,26]. The Hadron Spectrum Collaboration calculation [21,27] considered several moving frames and lattice volumes with quark masses such that the pion has a mass of 391 MeV down to 236 MeV.…”