Dalitz plot analysis of the decay ω→π+π−π0

Abstract

Using a low-background sample of 2.6 × 10 5 J=ψ → ωηðω → π þ π − π 0 ; η → γγÞ events, about 5 times larger statistics than previous experiments, we present a Dalitz plot analysis of the decay ω → π þ π − π 0 . It is found that the Dalitz plot distribution differs from the pure P-wave phase space with a statistical significance of 18.9σ. The parameters from the fit to data are in reasonable agreement with those without the cross-channel effect within the dispersive framework, which indicates that the cross-channel effect in ω → π þ π − π 0 is not significant.

Light Hadron Physics at BESIII Collaboration

“…A fit on the polar angle distribution of the radiative photon favor J PC = 0 −+ assignment for the two resonances. The obtained resonant parameters and J PC supports the two new observed resonances are η(1475) and X(1835), respectively, and this is for the first time we 2.2 PWA of J/ψ → γK S K S [9] An amplitude analysis of the K S K S system produced in radiative J/ψ decays is performed with both mass-dependent and mass-independent approaches. The mass-dependent analysis is performed by parameterizing the K S K S invariant mass spectrum as a sum of Breit-Wigner line shapes.…”

$$\omega \rightarrow 3\pi $$ and $$\omega \pi ^{0}$$ transition form factor revisited

“…3.1 and 3.2, our results for the Dalitz-plot parameters are in agreement with those of the BESIII experiment. Nonetheless, we must recall here that the disagreement between the BESIII [35] Dalitz-plot parameters and that obtained with unsubtracted KT equations [21,22] lies only in the α parameter, as can be seen in Table 1. In particular, the 3-parameter determinations give α = 111(18), 77, and 80, respectively.…”

“…The situation changed recently when the high-statistics data from BESIII became available [35]. A new set of ω → 3π Dalitz-plot parameters was extracted from the data and was found to differ significantly from the predictions based on (unsubtracted) dispersion relations of the KT equations [21,22].…”

“…(a) the recent determination of the ω → 3π decay Dalitz plot parameters by BESIII [35], shown in Table 1. We note that there are two different determinations, labeled as "2 par."…”

Experimental input for the HLbL contribution to themuon(g−2)

“…First observation of a deviation from P-wave phase space consistent with ρ meson contribution was reported by WASA-at-COSY [49]. Recently high statistics result from BESIII was released [50], with accuracy allowing to test dispersive calculations [51,52].…”