Diffractive production of $\rho^0 (770)$ mesons in muon-proton interactions at 470 GeV

The diffractive production of rho(0)(770) mesons in muon-proton interactions is studied in the kinematic region 0.15 GeV2 < Q(2) < 20 GeV2 and 20 GeV < nu < 420 GeV. The data were obtained in the Fermilab fixed-target experiment E665 with primary muons of 470 GeV Energy. Results are presented on the Q(2), x and nu dependence of the cross section, on the share of the pi(+)pi(-) mass spectrum, on the slope of the diffraction peak and on the production and decay angular distributions of the rho(0)(770). The cross section for diffractive production of rho(0) by virtual photons on protons depends mainly on Q(2). At fixed Q(2), no significant dependence on x or nu is observed. The extrapolation to Q(2) = 0 yields a photoproduction cross section of (10.30 +/- 0.33) mu b. The slope of the t' distribution has a value of (7.0 +/- 0.2) GeV-2, with a tendency to decrease as Q(2) increases. The production and decay angular distributions of the rho(0) depend strongly on Q(2) and are consistent with s-channel helicity conservation. The ratio R = sigma(L)/sigma(T) deduced from the decay angular distributions rises strongly with Q(2), passing the value of I at Q(2) approximate to 2 GeV2.