Measurement of the Cross Section for Open-Beauty Production in Photon-Photon Collisions at LEP

TL;DR

This paper measures the cross section of open-beauty production in photon-photon collisions at LEP, revealing a significant excess over theoretical predictions, using a large dataset and identifying b quarks via semi-leptonic decays.

Contribution

It provides the first comprehensive measurement of open-beauty production cross section in photon-photon collisions at LEP energies, highlighting discrepancies with existing models.

Findings

Measured cross section exceeds Monte Carlo predictions.

Results show significant excess over NLO QCD calculations.

Data covers a broad energy range from 189GeV to 209GeV.

Abstract

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 of integrated luminosity for electron-positron centre-of-mass energies from 189GeV to 209GeV. Events containing b quarks are identified through their semi-leptonic decay into electrons or muons. The e+e- -> e+e-b b~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.