Determination of theη-η′mixing angle

Abstract

We extract -0 mixing angle and the ratios of decay constants of light pseudoscalar mesons 0 , , and 0 using recently available BABAR measurements on -photon and 0 -photon transition form factors and more accurate experimental data for the masses and two-photon decay widths of the light pseduoscalar mesons.

Revisiting the radiative decays J/ψ → γη(′) in perturbative QCD

“…For the three phenomenological parameters, i.e., the mixing angle φ and the decay constants f q , f s , they have been determined in different methods [10,[45][46][47][48]. Here we take the up-to-date values from Refs.…”

SU(3) inDdecays: From 30% symmetry breaking to10−4precision

“…In order to determine Re ǫ 0 from (77) one would have to know also |A(K 0 η ′ )| and the relative strong phase between this amplitude and A(K 0 η), using a favored value for the η-η ′ mixing angle [37]. The other U-spin breaking parameter, Re ǫ …”

Proton-η′ interactions at threshold

“…The η -meson is a member of the nonet of ground-state pseudoscalar mesons. Unlike other meson nonets, the η -meson within the pseudoscalar nonet is nearly a pure SU(3) singlet state and may even contain contributions from a pseudoscalar glueball [1][2][3][4][5][6]. The octet of pseudoscalar mesons plays the role of Goldstone bosons; in the chiral limit of QCD when the quark masses go to zero, their masses vanish as well.…”

“…The modulus of the η p scattering length depends only weakly on the existence of a narrow D-wave resonance at the η p threshold. Since we do not know if a narrow resonance exists or not, we quote |a pη | = (0.403 ± 0.020 ± 0.060) fm (4) as our final result, where the first uncertainty is statistical, the second one is nature. The phase relative to the η production threshold is…”