High precision charmonium spectroscopy in annihilations

Abstract Fermilab experiment E835 studies the direct formation of charmonium states in proton-antiproton annihilations, obtained by intersecting the p beam of the Fermilab Antiproton Accumulator with an internal hydrogen jet target. In this paper we report the preliminary results from the 1996/1997 run, in particular about η c mass and width, search for η ′ c and first observation of the χ 0 state in p p annihilations.