Some hadronic parameters of charmonia in $$\varvec{N_{\text {f}}=2}$$ N f = 2 lattice QCD

Abstract

The phenomenology of leptonic decays of quarkonia holds many interesting features: for instance, it can establish constraints on scenarios beyond the Standard Model with the Higgs sector enriched by a light CP-odd state. In the following paper, we report on a two-flavor lattice QCD study of the η c and J/ψ decay constants, f η c = 387(3)(3) MeV and f J/ψ = 399(4)(2) MeV. We also examine some properties of the first radial excitation η c (2S) and ψ(2S).

Charmonium properties from lattice QCD+QED : Hyperfine splitting, J/ψ leptonic width, charm quark mass, and Hatton1, Davies2, Galloway3 et al. 2020Phys. Rev. D596680View full textAdd to dashboardCite

“…The calculation of [64] uses twisted-mass quarks on n f ¼ 2 gluon field configurations and obtains f η c ¼387ð7Þð2ÞMeV and f J=ψ ¼418ð8Þð5ÞMeV. The calculation of [65] uses clover quarks on n f ¼ 2 CLS gluon-field configurations to give f η c ¼ 387ð3Þð3Þ MeV and f J=ψ ¼ 399ð4Þð2Þ MeV. The n f ¼ 2 results for f η c agree with each other and have a central value about 2σ below ours.…”

Charming new B-physics

“…For the non-perturbative decay constant of the J/ψ resonance, we take the value from the phenomenological study in [73] f J/ψ = (407 ± 6) MeV . This value agrees well with the lattice determinations in [73][74][75]. The form factor can be determined via LCSR [76] or extrapolated from lattice simulations [77,78].…”

Charmonium properties from lattice QCD + QED: hyperfine splitting, $J/ψ$ leptonic width, charm quark mass and $a_μ^c$

“…field configurations and obtains f ηc =387(7)(2) MeV and f J/ψ =418(8)(5) MeV. The calculation of [63] uses clover quarks on n f = 2 CLS gluon-field configurations to give f ηc =387(3)(3) MeV and f J/ψ =399(4)(2) MeV. The n f = 2 results for f ηc agree with each other and have a central value about 2σ below ours.…”