BESIII Completes R-QCD Data Taking in 2-3 GeV Energy Range


After four months of hard work, the Beijing Spectrometer (BESIII) International Collaboration completed its data taking run in the 2-3 GeV low energy range by May 1st, 2015 .   

The goal of this round of experiments is R value measurement and QCD related studies in the low energy range. The range of data acquisition is from 3.08 GeV all the way down to 2 GeV, the lowest energy of BEPCII. With close cooperation between the accelerator staff and BESIII researchers, data was taken according to plan at 19 energy points. In line with the analysis, data taking was added at the 2.05 GeV energy point. The total integrated luminosity reached 525.5 pb^-1, which is the largest accumulation in the world for this energy range. This is significant for the R value measurement and for examining QCD.