出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：The results of the high precision J=y and y(2S) mass measurements carried out at the
VEPP-4M collider in 2002 with the KEDR detector and the preliminary results of the
y(2S) and y(3770) scans in 2004 have been presented. The resonant depolarization
method was used to calibrate absolute beam energy. The mass determination accuracy is
12 keV for J=y and 20 keV for y(2S). For the relatively broad y(3770) state the accuracy
of the mass measurement is approximately two times better than that of the current world
average value.
