ISSN - 00319007, EISSN - 10797114, Physical Review Letters, 2004, vol. 92, p. 142002-1
Measurements of the mass and width of the ηc meson and of an ηc(2S) candidate
The physical characteristics such as mass and total width of ηc meson were analyzed in two-photon interactions. The hyperfine separations were found to be directly related to spin-spin interactions. The momenta of charged particles were measured and their trajectories reconstructed with two detector systems which were located in 1.5 T solenoidal magnetic field. The charged particle identification was provided by detector of internally reflected Cherenkov light. The mass resolution was determined by fitting the distribution of difference between reconstructed mass and generated mass to Gaussian function.