Study of the Y (4260) resonance in e+e- collisions with initial state radiation at Belle

Abstract

We present a study of Y(4260) properties using the initial-state radiation process e^+e^- -> gamma_{ISR} Y(4260). The Y(4260) resonance is reconstructed in the pi^+ pi^- J/ψdecay mode, using data collected by the Belle detector at the KEKB e^+e^- collider. We find a significant signal with a central mass value of (4295 +-10 +10 -3) MeV/c^2 and a width of (133 +-26 +13 -6) MeV/c^2. We find Gamma_{ee}.B(Y(4260) -> pi^+ pi^- J/ψ) = (8.7 +- 1.1 +0.3 -0.9) eV. These results are preliminary.