Measurement of the f1(1285) → π+π−π0 decay

Light axial vector mesons

“…The observed decay channels a 1 (1260) 1230 ± 40 250 ∼ 600 3π [2], πρ [3], σπ [4] a 1 (1640) ♮ 1647 ± 22 254 ± 27 3π [5], πρ [4,6] , σπ [5], f 2 (1270)π [5] 1 − (1 ++ ) a 1 [13], ηππ [14][15][16], a 0 π [15][16][17], KKπ [15,16,18] f 1 (1420) 1426.4 ± 0.9 54.9 ± 2.6 KKπ [19,20], KK * (892)+c.c [18][19][20] model was widely applied to study the OZI-allowed two-body strong decay of hadrons . In the following, we briefly introduce the QPC model.…”

Strong isospin breaking at production of light scalars

“…As for the f 1 (1285) → f 0 (980)π 0 → 3π decay [31], its description requires the "terrible" a 0 0 (980)−f 0 (980) mixing:…”

“…Nowadays, this phenomenon has been discovered experimentally and studied with the help of detectors VES in Protvino [30,31] and BESIII in Beijing [32][33][34] in the processes (a) π − N → π − f 1 (1285)N → π − f 0 (980)π 0 N → → π − π + π − π 0 N [30, 31], (b) J/ψ → φf 0 (980) → φa 0 (980) → φηπ 0 [32], (c) χ c1 → a 0 (980)π 0 → f 0 (980)π 0 → π + π − π 0 [32], (d) J/ψ → γη(1405) → γf 0 (980)π 0 → γ 3π [33], (e) J/ψ → φf 0 (980)π 0 → φ 3π [34], (f) J/ψ → φf 1 (1285) → φf 0 (980)π 0 → φ 3π [34] It has become clear [35,36] that the similar isospin breaking effect can appear not only due to the a 0 0 (980)−f 0 (980) mixing, but also for any mechanism of the production of the KK pairs in the S wave, X → KK → f 0 (980)/a 0 0 (980). 1 Thus a new tool to study the production mechanism and nature of light scalars is emerged.…”