Study of η(1405)/η(1475) in J/psi to gamma {K}_S^0{K}_S^0{pi}^0 decay

Abstract

Using a sample of (10.09 ± 0.04) × 109J/ψ decays collected with the BESIII detector, partial wave analyses of the decay J/psi to gamma {K}_S^0{K}_S^0{pi}^0 are performed within the {K}_S^0{K}_S^0{pi}^0 invariant mass region below 1.6 GeV/c2. The covariant tensor amplitude method is used in both mass independent and mass dependent approaches. Both analysis approaches exhibit dominant pseudoscalar and axial vector components, and show good consistency for the other individual components. Furthermore, the mass dependent analysis reveals that the {K}_S^0{K}_S^0{pi}^0 invariant mass spectrum for the pseudoscalar component can be well described with two isoscalar resonant states using relativistic Breit-Wigner model, i.e., the η(1405) with a mass of 1391.7pm {0.7}_{-0.3}^{+11.3} MeV/c2 and a width of 60.8pm {1.2}_{-12.0}^{+5.5} MeV, and the η(1475) with a mass of 1507.6pm {1.6}_{-32.2}^{+15.5} MeV/c2 and a width of 115.8pm {2.4}_{-10.9}^{+14.8} MeV. The first and second uncertainties are statistical and systematic, respectively. Alternate models for the pseudoscalar component are also tested, but the description of the {K}_S^0{K}_S^0{pi}^0 invariant mass spectrum deteriorates significantly.