| Article | |||
| Report number | arXiv:2503.09895 ; MITP-25-021 ; CERN-TH-2025-052 | ||
| Title | $\eta$, $\eta^\prime$ mesons from lattice QCD in fully physical conditions | ||
| Author(s) | Ottnad, Konstantin (U. Mainz, PRISMA ; Mainz U., Inst. Kernphys.) ;Bacchio, Simone (Cyprus Inst.) ;Finkenrath, Jacob (CERN) ;Kostrzewa, Bartosz (Bonn U., HISKP ; U. Bonn, Phys. Inst., BCTP) ;Petschlies, Marcus (Bonn U., HISKP ; U. Bonn, Phys. Inst., BCTP) ;Pittler, Ferenc (Cyprus Inst.) ;Urbach, Carsten (Bonn U., HISKP ; U. Bonn, Phys. Inst., BCTP) ;Wenger, Urs (Bern U.) | ||
| 2025 | |||
| 2025-03-12 | |||
| 22 | |||
| Eur. Phys. J. A 61 (2025) 169 | |||
| 10.1140/epja/s10050-025-01635-0 | |||
| Particle Physics - Lattice | |||
| We determine masses and mixing parameters of the $\eta$ and $M_{\eta^\prime}$ meson in lattice QCD. The calculations are carried out on a set of 13 ETMC gauge ensembles with $N_f=2+1+1$ (maximally) twisted-mass Clover-improved quarks. These ensemble cover four values of the lattice spacing $a=0.057\mathrm{fm},...,0.092\mathrm{fm}$ and pion masses from $140\mathrm{MeV}$ to $360\mathrm{MeV}$, including three ensembles at physical quark masses and six ensembles with $M_\pi<200\mathrm{MeV}$. The strange-quark contribution is treated in a mixed-action approach using Osterwalder-Seiler fermions to avoid complications due to flavor mixing in the heavy quark sector and to enable the use of the one-end trick in the computation of strange quark-disconnected diagrams. With the strange-quark mass tuned to its physical value and several ensembles having close-to-physical light-quark mass, uncertainties related to the chiral extrapolations are reduced significantly compared to earlier studies. Physical results are computed with fully controlled systematics from a combined chiral, continuum and infinite-volume extrapolation, and a full error budget is obtained from model averages over of various fit ansätze and data cuts. Our results for the masses are given by $M_\eta=551(16)\mathrm{MeV}$ and $M_{\eta^\prime}=972(20)\mathrm{MeV}$, respectively, where statistical and systematic errors have been added in quadrature. For the mixing angle and decay-constant parameters the Feldmann-Kroll-Stech scheme is employed to compute them from pseudoscalar matrix elements in the quark-flavor basis. For the mixing angle we obtain $\phi^\mathrm{phys}=39.3(2.0)^\circ$ and our results for the decay-constant parameters are given by $f_l^\mathrm{phys}=138.6(4.4)\mathrm{MeV}$ and $f_s^\mathrm{phys}=170.7(3.3)\mathrm{MeV}$. | |||
| preprint: (License:arXiv nonexclusive-distrib 1.0) publication: © 2025 The Author(s) (License:CC-BY-4.0) | |||
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Record created 2025-03-15, last modified 2025-08-12
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