Measurement of exclusive ρ +ρ - production in high-Q 2 two-photon collisions at LEP

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<209GeV with a total integrated luminosity of 854.7 pb -1. The cross section of the process γγ*→ρ +ρ - is determined as a function of the photon virtuality, Q 2, and the two-photon centre-of-mass energy, W γγ, in the kinematic region: 1.2<Q 2<30GeV 2 and 1.1<W γγ<3GeV. The ρ +ρ - production cross section is found to be of the same magnitude as the cross section of the process γγ *→ρ 0ρ 0, measured in the same kinematic region by L3, and to have similar W γγ and Q 2 dependences. © 2004 Published by Elsevier B.V.