Central mass energy determination in high precision experiments on VEPP-4M

The series of experiments on mass measurements of J/psi, psi' and psi" mesons have been done on VEPP-4M collider. The accuracy of obtained mass values for J/psi- and psi'- mesons exceeded the world values about 3 times, based on experiments on VEPP-4 [1] and E760[2]. The ongoing experiment on tau lepton mass measurement is expected to achieve accuracy 1.5-2 times better than the present world value. The present paper describes the process and uncertainties of luminosity weighted interaction energy definition. The errors of interaction energy include uncertainties due to beam energy calibration by resonant depolarization technique and errors of interaction energy calculation.