Correlation analysis in time-of-flight calibration of BESIII

The errors and correlations of BESIII TOF measurements are carefully checked in hit position at z partitions with the electron-pair events. The measured time-of-flight's and their covariance matrices are subjected to a correlation analysis algorithm which is developed for BESIII to combine the independent measurements with common errors. Monte Carlo studies show that the correlated analysis can provide more reliable TOF information on particle identification. (authors)