Diffractively produced charm final states in 800 GeV/c proton-proton collisions.

摘要

We report the observation of charm final states produced in the single diffractive dissociative reactions (1) pp → pX(D*+ → (D 0 → K-pi+)pi +) and (2) pp → pX( D*- → (D¯ 0 → K+pi-)pi -). These results are based on the over 5 billion event data sample acquired by Fermilab experiment E690 during the fixed target run of 1991. In this run, an 800 GeV/c incident proton beam was used with a liquid hydrogen target. We measure cross sections of [0.209 +/- 0.050 stat+.083 -.040 (syst)] mub and [0.196 +/- 0.043 stat+.014 -.046 (syst)] mub for reactions (1) and (2), respectively. These results are compared with model predictions and results from other experiments. Our results are significantly lower than predictions based on the diffractive model of Ingelman and Schlein using a flat or a hard pomeron structure function.