From 2011 to 2014,the BESIII experiment collected about 5 fb-1 data at center-of-mass energies around 4 GeV for the studies of the charmonium-like and higher excited charmonium states.By analyzing the di-muon process e+e- → Yisr/fsr μ+μ-,the center-of-mass energies of the data samples are measured with a precision of 0.8 MeV.The center-of-mass energy is found to be stable for most of the time during data taking.
From 2011 to 2014, the BESIII experiment collected about 5 fb^-1 data at center-of-mass energies around 4 GeV for the studies of the charmonium-like and higher excited charmonium states. By analyzing the di-muon process e＋e- →yma/Fsμ^＋μ^-, the center-of-mass energies of the data samples are measured with a precision of 0.8 MeV. The center-of-mass energy is found to be stable for most of the time during data taking.
Chinese Physica C
Supported by National Key Basic Research Program of China （2015CB856700）, National Natural Science Foundation of China （11125525, 11235011, 11322544, 11335008, 11425524, Y61137005C）, Chinese Academy of Sciences （CAS） Large-Scale Scientific Facility Program, CAS Center for Excellence in Particle Physics （CCEPP）, Collaborative Innovation Center for Particles and Interactions （CICPI）, Joint Large-Scale Scientific Facility Funds of NSFC and CAS （11179007, U1232201, U1332201）, CAS （KJCX2-YW-N29, KJCX2-YW- N45）, 100 Talents Program of CAS, National 1000 Talents Program of China, INPAC and Shanghai Key Laboratory for Particle Physics and Cosmology, German Research Foundation DFG （Collaborative Research Center CRC-1044）, Istituto Nazionale di Fisica Nucleare, Italy, Ministry of Development of Turkey （DPT2006K-120470）, Russian Foundation for Basic Research （14-07-91152）, Swedish Research Council, U. S. Department of Energy （DE-FGO2-O4ER41291, DE-FG02-05ER41374, DE-FG02-94ER40823, DESC0010118）, U.S. National Science Foundation, University of Groningen （RUG） and Helmholtzzentrum fuer Schwerionenforschung GmbH （GSI）, Darmstadt, WCU Program of National Research Foundation of Korea （R32-2008-000-10155-0）.