Measurement of the I = 1/2 Kπ S-Wave Amplitude from Dalitz Plot Analyses of η_c → KK̅π in Two-Photon Interactions


We study the processes γγ→K(S)⁰ K^± π^∓ and γγ→K⁺K⁻π⁰ using a data sample of 519 fb⁻¹ recorded with the BABAR detector operating at the SLAC PEP-II asymmetric-energy e⁺e⁻ collider at center-of-mass energies at and near the Υ(nS) (n=2, 3, 4) resonances. We observe η(c) decays to both final states and perform Dalitz plot analyses using a model-independent partial wave analysis technique. This allows a model-independent measurement of the mass-dependence of the I = 1/2 KπS-wave amplitude and phase. A comparison between the present measurement and those from previous experiments indicates similar behavior for the phase up to a mass of 1.5 GeV/c². In contrast, the amplitudes show very marked differences. The data require the presence of a new a₀(1950) resonance with parameters m=1931 ±14 ± 22 MeV/c² and Γ=271 ± 22 ± 29 MeV.



Kaons, Scattering amplitude (Nuclear physics), Mass spectrometry, Mesons, Legendre's polynomials, Dalitz plots

The work of A. Palano and M. R. Pennington was supported (in part) by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contract No. DE-AC05-06OR23177


©2016 American Physical Society