Determination of the number of $\psi^{\prime}$ event at BESIII
  The number of $\psp$ events accumulated by the BESIII experiment from March 3 through April 14, 2009, is determined by counting inclusive hadronic events. The result is $106.41\times(1.00\pm 0.81%)\times 10^{6} $. The error is systematic only; the statistical error is negligible. 
M.Ablikim, M. N. Achasov, D.J. Ambrose
hep-ex