Precision measurements of charmonium states formed inpp¯annihilation

Fermilab experiment E-760 studies the resonant formation of charmonium states in proton-antiproton interactions using a hydrogen gas-jet target in the Antiproton Accumulator ring at Fermilab. Precision measurements of the mass and width of the charmonium states ${\mathrm{\chi }}_{\mathit{c}1}$,${\mathrm{\chi }}_{\mathit{c}2}$, a direct measurement of the ψ’ width, and a new precision measurement of the J/ψ mass are presented.