Measurement of exclusive ρ+ρ−ρ+ρ− production in high-Q2Q2 two-photon collisions at LEP

Abstract

Exclusive ρ + ρ − production in two-photon collisions involving a single highly-virtual photon is studied for the first time with data collected by the L3 experiment at LEP at centre-of-mass energies 89 < s < 209 GeV with a total integrated luminosity of 854.7 pb − 1 . The cross section of the process γ γ * → ρ + ρ − is determined as a function of the photon virtuality, Q 2 , and the two-photon centre-of-mass energy, W γ γ , in the kinematic region: 1.2 < Q 2 < 30 GeV 2 and 1.1 < W γ γ < 3 GeV . The ρ + ρ − production cross section is found to be of the same magnitude as the cross section of the process γ γ * → ρ 0 ρ 0 , measured in the same kinematic region by L3, and to have similar W γ γ and Q 2 dependences.