Bottomonium Results from BABAR and BELLE

TL;DR

This paper reports on bottomonium measurements from BABAR and BELLE, including the observation of eta_b and cross section enhancements, advancing understanding of bottomonium states and production mechanisms.

Contribution

It presents new measurements of bottomonium states and cross sections, including the eta_b observation and energy-dependent cross section data from BABAR and BELLE.

Findings

Observation of the eta_b ground state.

Measurement of the e+e- -> b bbar cross section from 10.54 to 11.20 GeV.

Detection of an enhancement in Upsilon(nS) pi+ pi- production cross section.

Abstract

After nine years of operation the BABAR experiment at the B factory PEPII (Standford Linear Accelerator Center) stopped data taking in April 2008. The last three month of data taking were devoted to e+e- collisions at center of mass energies of the Upsilon(2S), Upsilon(3S) and to an energy scan above the Upsilon(4S). Besides the observation of the bottomonium ground state eta_b, the center of mass energy dependent e+e- -> b bbar cross section was measured in the energy range from 10.54 to 11.20 GeV. BELLE observed an enhancement in the production cross section for e+e- -> Upsilon(nS) pi+ pi- -> mu+ mu- pi+ pi- in an energy scan from 10.83 to 11.02 GeV.