2024/09/20 by Ziwen Fu, Jun Wang, Fu, Ziwen +1
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Lattice (hep-lat) #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2409.13197
openalex publication_date 2024/09/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29
The I=2 ππ elastic s-wave scattering phase shift is measured by lattice QCD with Nf=3 flavors of the Asqtad-improved staggered fermions. The lattice-calculated energy-eigenvalues of ππ systems at one center of mass frame and some moving frames using the moving wall source technique are utilized to secure phase shifts by Lüscher's formula. Our computations are fine enough to obtain threshold parameters: scattering length a, effective range r, and shape parameter P, which can be extrapolated at the physical point by NLO in chiral perturbation theory, and our relevant NNLO predictions from expanding NPLQCD's works are novelly considered as the systematic uncertainties. Our outcomes are consistent with Roy equation determinations, newer experimental data, and lattice estimations. Numerical computations are performed with a coarse (a≈0.12~fm, L3 T = 323 64), two fine (a≈0.09~fm, L3 T = 403 96) and a superfine (a≈0.06~fm, L3 T = 483 144) lattice ensembles at four pion masses of mπ∼247~\rm MeV, 249~\rm MeV, 275~\rm MeV, and 384~\rm MeV, respectively.