Bottom Production in Two-Photon Collisions at LEP

TL;DR

This paper reports measurements of bottom quark production in two-photon collisions at LEP, revealing a significant discrepancy between observed cross sections and theoretical predictions, and includes a candidate eta_b meson observation.

Contribution

It provides the first detailed experimental measurements of inclusive and exclusive bottom production in gamma-gamma collisions at LEP energies, highlighting a notable deviation from NLO QCD calculations.

Findings

Measured inclusive bottom production cross section: 13.3 +- 1.5 +- 2.3 pb.

Observed a candidate eta_b meson at 9.30 GeV.

Next-to-leading order calculations are three times lower than the measured data.

Abstract

Results on inclusive and exclusive bottom production in gammagamma collisions are presented. The total cross section of inclusive bottom production is investigated through its leptonic decays at LEP II energies by the experiments L3 and OPAL. The average cross section, after correction for acceptances and efficiencies, is sigma_tot = 13.3 +- 1.5 +- 2.3 pb. The next-to-leading order calculations are lower than the data by a factor three, which corresponds to a difference of more than three standard deviations. ALEPH studied the exclusive bottom production. Searching for the eta_b one candidate is found. Limits on Gamma_gammagamma(eta_b)*BR for 4 and 6 charged particles are extracted. The candidate has a mass of 9.30 +- 0.04 GeV.