ISSN - 03702693, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 2003, vol. 573, p. 63-79
New precision measurement of the J/ψ- and ψ′-meson masses
A new high precision measurement of the J/ψ- and ψ′-meson masses has been performed at the VEPP-4M collider using the KEDR detector. The resonant depolarization method has been employed for the absolute calibration of the beam energy. The following mass values have been obtained: M J/ψ = 3096.9174 ± 0.010 ± 0.0007 MeV, M ψ′ = 3686.111 ± 0.025 ± 0.009 MeV. The relative measurement accuracy has reached 4 × 10-6 for J/ψ and 7 × 10-6 for ψ′, approximately 3 times better than in the previous precise experiments. © 2003 Elsevier B.V. All rights reserved.