2017/10/31 by Konstantin Ottnad, Carsten Urbach · 2 citations
Physics and Astronomy · #Chiral perturbation theory #Extrapolation #Fermion #High-Energy Particle Collisions Research #Lattice (music) #Lattice constant #Meson #Particle physics #Particle physics theoretical and experimental studies #Physics #Pion #Quantum Chromodynamics and Particle Interactions #Quantum mechanics #Statistics #hep-lat #hep-ph
paper · pdf · doi:10.1103/physrevd.97.054508
published as Phys. Rev. D 97, 054508 (2018) · 22 pages, 8 figures, 12 tables; matching version accepted for publication
openalex created_date 2017/11/10 · arxiv created 2018/03/18 · openalex publication_date 2018/03/19 · arxiv updated 2018/03/28 · openalex updated_date 2026/08/05
We present an improved analysis of our lattice data for the \ensuremathη--\ensuremathη^\ensuremath' system, including a correction of the relevant correlation functions for residual topological finite size effects and employing consistent chiral and continuum fits. From this analysis we update our physical results for the masses M_\ensuremathη=557(11)stat(03)_\ensuremathχPT MeV and M_\ensuremathη^\ensuremath'=911(64)stat(03)_\ensuremathχPT MeV, as well as the mixing angle in the quark flavor basis \ensuremathφ=38.8(2.2)stat(2.4)_\ensuremathχPT^\ensuremath∘ in excellent agreement with other results from phenomenology. Similarly, we include an analysis for the decay constant parameters, leading to fl=125(5)stat(6)_\ensuremathχPT MeV and fs=178(4)stat(1)_\ensuremathχPT MeV. The second error reflects the uncertainty related to the chiral extrapolation. The data used for this study has been generated on gauge ensembles provided by the European Twisted Mass Collaboration with Nf=2+1+1 dynamical flavors of Wilson twisted mass fermions. These ensembles cover a range of pion masses from 220 MeV to 500 MeV and three values of the lattice spacing. Combining our data with a prediction from chiral perturbation theory, we give an estimate for the physical \ensuremathη, \ensuremathη^\ensuremath'\ensuremath→\ensuremathγ\ensuremathγ decay widths and the singly-virtual \ensuremathη, \ensuremathη^\ensuremath'\ensuremath→\ensuremathγ\ensuremathγ* transition form factors in the limit of large momentum transfer.