Chiral extrapolations of the ρ(770) meson in Nf=2+1 lattice QCD simulations

Abstract

Recent N f = 2 + 1 lattice data for meson-meson scattering in p-wave and isospin I = 1 are analyzed using a unitarized model inspired by Chiral Perturbation Theory in the inverse-amplitude formulation for two and three flavors. Chiral extrapolations are performed that postdict phase shifts extracted from experiment quite well. In addition, the low-energy constants are compared to the ones from a recent analysis of N f = 2 lattice QCD simulations to check for the consistency of the hadronic model used here. Some inconsistencies are detected in the fits to N f = 2 + 1 data, in contrast to the previous analysis of N f = 2 data.

The I = 1 pion–pion scattering amplitude and timelike pion form factor from Nf = 2 + 1 lattice QCD

“…While we do not perform continuum and chiral extrapolations here, our data can be used for future such extrapolations. Chiral extrapolations of lattice scattering data using unitarized extensions of chiral effective theory [65,[67][68][69][70][71][72][73][74] have been performed, although to date cutoff effects have not been considered. Nonetheless, it is evident in our data that cutoff effects in both the scattering amplitude (shown in Fig.…”

“…In order to extrapolate to the physical point and continuum, a range of pion masses m π = 200 − 280 MeV and lattice spacings a = 0.050 − 0.086 fm are employed. Such extrapolations have been performed recently using chiral perturbation theory and its extensions [63][64][65][66][67][68][69][70][71][72][73][74] and treat all scattering data simultaneously. As these extrapolations are somewhat involved and have not yet treated cutoff effects, we present the determination of the amplitudes only in this work and leave extrapolation to the physical quark masses and continuum for the future.…”

Cross-channel study of pion scattering from lattice QCD

“…The physical parameters, such as scattering lengths, resonance pole positions and couplings have been discussed in length in the previous papers, dealing with single channels [27,40,50,52]. There the dependence on the utilized model has been discussed using a broad class of chiral unitary models, Breit-Wigner type, and models based on conformal mapping.…”

Extraction of isoscalar ππ phase shifts from lattice QCD

“…Second, we employ a model based on the chiral unitary approach (UChPT), used, e.g., in Refs. [9,27,28]. Subsequently, the UChPT amplitude is extrapolated to the physical point.…”