Measurement of the cross section for open-beauty production in photon-photon collisions at LEP

The cross section for open-beauty production in photon-photon collisions is measured using the whole high-energy and high-luminosity data sample collected by the L3 detector at LEP. This corresponds to 627 pb−1 of integrated luminosity for electron-positron centre-of-mass energies from 189 to 209 GeV. Events containing b quarks are identified through their semi-leptonic decay into electrons or muons. The e+e−→e+e−bb¯X cross section is measured within our fiducial volume and then extrapolated to the full phase space. These results are found to be in significant excess with respect to Monte Carlo predictions and next-to-leading order QCD calculations.