Precise measurement of spin-averaged chi_{cJ}(1P) mass using photon conversions in psi(2S) -> gamma chi_{cJ}

M. Ablikim, J. Z. Bai

Using photon conversions to e^+e^- pairs, the energy spectrum of inclusive photons from psi(2S) radiative decays is measured by BESII at the Beijing Electron-Positron Collider. The…