To investigate the nature of the Ψ（3770） resonance and to measure the cross section for e^＋e^-→DD, a cross-section scan data sample, distributed among 41 center-of-mass energy points from 3.73 to 3.89 GeV, was ta...To investigate the nature of the Ψ（3770） resonance and to measure the cross section for e^＋e^-→DD, a cross-section scan data sample, distributed among 41 center-of-mass energy points from 3.73 to 3.89 GeV, was taken with the BESIII detector operated at the BEPCII collider in the year 2010. By analyzing the large angle Bhabha scattering events, we measure the integrated luminosity of the data sample at each center-of-mass energy point. The total integrated luminosity of the data sample is 76.16±0.04±0.61 pb^-1, where the first uncertainty is statistical and the second systematic.展开更多
Data sets were collected with the BESⅢ detector at the BEPCⅡ collider at the center-of-mass energy of √s=3.650 GeV during May 2009 and at √s=3.773 GeV from January 2010 to May 2011. By analyzing the large angle Bh...Data sets were collected with the BESⅢ detector at the BEPCⅡ collider at the center-of-mass energy of √s=3.650 GeV during May 2009 and at √s=3.773 GeV from January 2010 to May 2011. By analyzing the large angle Bhabha scattering events, the integrated luminosities of the two data sets are measured to be （44.49±0.02±0.44） pb-1 and （2916.94±0.18±29.17） pb-1, respectively, where the first error is statistical and the second error is systematic.展开更多
The BEPC II Luminosity Monitor （BLM） monitors relative luminosity per bunch. The counting rates of gamma photons, which are proportional to the luminosities from the BLM at the center of mass system energy of the φ...The BEPC II Luminosity Monitor （BLM） monitors relative luminosity per bunch. The counting rates of gamma photons, which are proportional to the luminosities from the BLM at the center of mass system energy of the φ（3770） resonance, are obtained with a statistical error of 0.01% and a systematic error of 4.1%. Absolute luminosities are also determined by the BESIII End-cap Electro-Magnetic Calorimeter （EEMC） using Bhabha events with a statistical error of 2.3% and a systematic error of 3.5%. The calibration constant between the luminosities obtained with the EEMC and the counting rates of the BLM are found to be 0.84±0.03 （×10^26 cm^-2-count^-1）. With the calibration constaat, the counting rates of the BLM can be scaled up to absolute luminosities.展开更多
基金Supported by National Key Basic Research Program of China(2015CB856700)National Natural Science Foundation of China(NSFC)(11235011,11335008,11425524,11625523,11635010)+13 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility Programthe CAS Center for Excellence in Particle Physics(CCEPP)Joint Large-Scale Scientific Facility Funds of the NSFCCAS(U1332201,U1532257,U1532258)CAS Key Research Program of Frontier Sciences(QYZDJ-SSW-SLH003,QYZDJ-SSW-SLH040)100 Talents Program of CASNational 1000 Talents Program of China,INPACShanghai Key Laboratory for Particle Physics and Cosmology,German Research Foundation DFG under Contracts Nos.Collaborative Research Center CRC 1044,FOR 2359Istituto Nazionale di Fisica Nucleare,Italy,Koninklijke Nederlandse Akademie van Wetenschappen(KNAW)(530-4CDP03)Ministry of Development of Turkey(DPT2006K-120470)National Science and Technology fundThe Swedish Research Council,U.S.Department of Energy(DEFG02-05ER41374,DE-SC-0010118,DE-SC-0010504,DE-SC-0012069)University of Groningen(RuG)and the Helmholtzzentrum fuer Schwerionenforschung GmbH(GSI)Darmstadt,WCU Program of National Research Foundation of Korea(R32-2008-000-10155-0)
文摘To investigate the nature of the Ψ（3770） resonance and to measure the cross section for e^＋e^-→DD, a cross-section scan data sample, distributed among 41 center-of-mass energy points from 3.73 to 3.89 GeV, was taken with the BESIII detector operated at the BEPCII collider in the year 2010. By analyzing the large angle Bhabha scattering events, we measure the integrated luminosity of the data sample at each center-of-mass energy point. The total integrated luminosity of the data sample is 76.16±0.04±0.61 pb^-1, where the first uncertainty is statistical and the second systematic.
基金Supported by the Ministry of Science and Technology of China(2009CB825204)National Natural Science Foundation of China(10625524,10821063,10825524,10835001,10935007,11125525,11235011)+7 种基金Joint Funds of the National Natural Science Foundation of China(11079008,11179007)Chinese Academy of Sciences Large-Scale Scientific Facility Program,CAS(KJCX2-YW-N29,KJCX2-YW-N45)100 Talents Program of CAS,German Research Foundation DFG(Collaborative Research Center CRC-1044)Istituto Nazionale di Fisica Nucleare,Italy,Ministry of Development of Turkey(DPT2006K-120470)U.S.Department of Energy(DE-FG02-04ER41291,DE-FG02-05ER41374,DE-FG02-94ER40823)U.S.National Science Foundation,University of Groningen(RuG)the Helmholtzzentrum fuer Schwerionenforschung GmbH(GSI)Darmstadt,WCU Program of National Research Foundation of Korea(R32-2008-000-10155-0)
文摘Data sets were collected with the BESⅢ detector at the BEPCⅡ collider at the center-of-mass energy of √s=3.650 GeV during May 2009 and at √s=3.773 GeV from January 2010 to May 2011. By analyzing the large angle Bhabha scattering events, the integrated luminosities of the two data sets are measured to be （44.49±0.02±0.44） pb-1 and （2916.94±0.18±29.17） pb-1, respectively, where the first error is statistical and the second error is systematic.
文摘The BEPC II Luminosity Monitor （BLM） monitors relative luminosity per bunch. The counting rates of gamma photons, which are proportional to the luminosities from the BLM at the center of mass system energy of the φ（3770） resonance, are obtained with a statistical error of 0.01% and a systematic error of 4.1%. Absolute luminosities are also determined by the BESIII End-cap Electro-Magnetic Calorimeter （EEMC） using Bhabha events with a statistical error of 2.3% and a systematic error of 3.5%. The calibration constant between the luminosities obtained with the EEMC and the counting rates of the BLM are found to be 0.84±0.03 （×10^26 cm^-2-count^-1）. With the calibration constaat, the counting rates of the BLM can be scaled up to absolute luminosities.
