Beam Energy Measurement by Resonant Depolarization Method at VEPP-4M

Abstract

Experiments on high precision mass measurement of particles require precise beam energy calibration. The most accurate method of beam energy measurement is the resonant depolarization technique. This article describes the beam energy measurement at the VEPP-4M storage ring using this method together with a Touschek polarimeter. The accuracy achieved is about 10 −6 . More than thousand energy calibrations were used in the KEDR detector for the precise experiments on the measurement of J/ψ, ψ(2S), ψ(3770), D + , D 0 meson and τ lepton masses.