Di ractive production of 0 ( 770 ) mesons in muon-protoninteractions at 470 GeVE 665

The diiractive production of 0 (770) mesons in muon-proton interactions is studied in the kinematic region 0.15 GeV 2 < Q 2 < 20 GeV 2 and 20 GeV < < 420 GeV. The data were obtained in the Fermilab xed-target experiment E665 with primary muons of 470 GeV energy. Results are presented on the Q 2 , x and dependence of the cross section, on the shape of the + ? mass spectrum, on the slope of the diiraction peak and on the production and decay angular distributions of the 0 (770). The cross section for diiractive production of 0 by virtual photons on protons depends mainly on Q 2. At xed Q 2 , no signiicant dependence on x or is observed. The extrapolation to Q 2 = 0 yields a photoproduction cross section of (10:30 0:33) b. The slope of the t 0 distribution has a value of (7:00:2) GeV ?2 , with a tendency to decrease as Q 2 increases. The production and decay angular distributions of the 0 depend strongly on Q 2 and are consistent with s-channel helicity conservation. The ratio R = L == T deduced from the decay angular distributions rises strongly with Q 2 , passing the value of 1 at Q 2 2 GeV 2 .