Speaker
Zekun Jia
Description
Using the BESIII detector, the R value has been measured on 14 energy points with the corresponding c.m. energies going from 2.2324 to 3.6710 GeV. The statistical uncertainty of the measured R is less than 0.6%. Two different simulation models, the LUARLW and a new Hybrid generator, have been used and give consistent detection efficiencies and initial-state-radiation corrections.
The accuracy in the R value measurements is better than 2.6% below 3.1 GeV and 3.0% above.
Author
Hao Zhang
(University of Science and Technology of China)
