| BESIII data quality checks and physics analysis of J/ψ,ψ(2S)→pnπ+c.c. are two parts of this thesis.Considering the complicacy of BESIII Offline Software System(BOSS), besides the checks from the software level, data quality checks from the physics level is needed to val-idate the performance of whole system, and to find the possible problems in BOSS. So the first part introduces the general contents of data quality checks, especially for checks of the software modules related to each sub-detector.The tracking and particle identification(particle ID) efficiency have been studied in detail in order to give a reliable results, which have been used as official values on the systematic errors of tracking and particle ID in the BESIII collaboration. Different methods have been tried and studied in the tracking and particle ID efficiency calculation. The influences of the noise, vetex cut, and long life particles are also investigate.The results of tracking and particle ID efficiency and the systematic errors both in 1-dimension and 2-dimension have been given in this part.Based on BESⅢ225M J/ψevents and 106Mψ(2S) events, J/ψ,ψ(2S)→pnπ+c.c. are studied, including the event selection and systematic errors analysis. The branching ratios are given finally and the "12% rules" have been proved. The branching ratios consist with BESⅡ, but background levels, statistic and systematic errors are much lower the BESII. Possible N* resonances are observed in the pπand nπinvariant mass, and a partial wave analysis(PWA) will be needed. |
