E decays to ηππ in annihilation at rest

Proton-antiproton annihilation and meson spectroscopy with the Crystal Barrel

“…To clarify whether the structures observed in J/ψ radiative decay and in pp annihilation are compatible and in particular to confirm the quantum numbers of E (0 −+ and not 1 ++ ) Crystal Barrel has searched for the ηππ decay mode of the E meson in the reaction pp → (ηπ + π − )π 0 π 0 and (ηπ 0 π 0 )π + π − , leading to two charged particles and 6γ (Amsler, 1995h;Urner, 1995). Since the rate for this reaction was expected to be rather small (∼ 10 −3 of all annihilations), an online trigger required 8 clusters in the barrel and at least two π 0 and one η.…”

Determining the gluonic content of isoscalar mesons

“…Further evidence for the low mass state, in the decay channel ηππ, comes from MarkIII [50] who find η(1400 ± 6), Γ tot = 47 ± 13 MeV; from DM2 [47] who find η(1398±6), Γ tot = 53±11 MeV; and the Crystal Barrel Collaboration [14]. The latter see pp → πη(1410 ± 3) → π(ηππ) with significant contribution in the glue favoured partial wave ησ [2].…”

“…The empirical situation with regard to f J (1710) and ξ(2230) is currently under investigation. The η(1440) is clearly seen in pp annihilation [13,14] 3. Glueballs should be enhanced compared to ordinary mesons in radiative quarkonium decay.…”

First Observation ofη(1405)Decays intof0(980)π0Ablikim1, Ачасов2, Alberto3 et al. 2012Phys. Rev. Lett.Self Cite962400View full textAdd to dashboardCite

“…The isospin violating decay η(1405) → f 0 (980)π 0 is observed for the first time with a statistical significance larger than 10σ in both the charged and neutral modes. According to our measurement, the ratio of Br(η(1405) → f 0 (980)π 0 → π + π − π 0 ) to Br(η(1405) → a 0 0 (980)π 0 → ηπ 0 π 0 ) is (17.9 ± 4.2)% [26,27], which is one order of magnitude larger than the a 0 0 (980) − f 0 (980) mixing intensity (less than 1%) determined at BESIII previously [28]. The measured width of the f 0 (980) is anomalously narrower than the world average.…”