Received 5 July 2016, Revised 26 August 2016 * Supported by National Key Basic Research Program of China (2015CB856700), National Natural Science Foundation of China (NSFC) (10805053, 11125525, 11175188, 11235011, 11322544, 11335008, 11425524) Abstract: A measurement of the number of J/ψ events collected with the BESIII detector in 2009 and 2012 is performed using inclusive decays of the J/ψ. The number of J/ψ events taken in 2009 is recalculated to be (223.7 ± 1.4) × 10 6 , which is in good agreement with the previous measurement, but with significantly improved precision due to improvements in the BESIII software. The number of J/ψ events taken in 2012 is determined to be (1086.9 ± 6.0) × 10 6 . In total, the number of J/ψ events collected with the BESIII detector is measured to be (1310.6 ± 7.0) × 10 6 , where the uncertainty is dominated by systematic effects and the statistical uncertainty is negligible.

49A,49C Y. Ding( ) 27 C. Dong( ) 30 J. Dong( ) 1,a L. Y. Dong( ) 1 M. Y. Dong( ) 1,a S. X. Du( ) 53 P. F. Duan( ) 1 J. Z. Fan( ) 39 J. Fang( ) 1,a S. S. Fang( ) 1 X. Fang( ) 46,a Y. Fang( ) 1 L. Fava 49B,49C F. Feldbauer 22Guo( ) 28 Y. Guo( ) 1 Y. P. Guo( ) 22 Z. Haddadi 25 A. Hafner 22 S. Han( ) 51 X. Q. Hao( ) 15 F. A. Harris 42 K. L. He( ) 1 T. Held 4 Y. K. Heng( ) 1,a Z. L. Hou( ) 1 C. Hu( ) 28 H. M. Hu( ) 1 J. F. Hu( ) 49A,49C T. Hu( ) 1,a Y. Hu( ) 1 G. M. Huang( ) 6 G. S. Huang( ) 46,a J. S. Huang( ) 15 X. T. Huang( ) 33 Y. Huang( ) 29 T. Hussain 48 Q. Ji( ) 1 Q. P. Ji( ) 30 X. B. Ji( ) 1 X. L. Ji( ) 1,a L. W. Jiang( ) 51 X. S. Jiang( ) 1,a X. Y. Jiang( ) 30 J. B. Jiao( ) 33 Z. Jiao( ) 17 D. P. Jin( ) 1,a S. Jin( )

By analyzing the large-angle Bhabha scattering events e+e− → (γ)e+e− and diphoton events e+e− → (γ)γγ for the data sets collected at center-of-mass (c.m.) energies between 2.2324 and 4.5900 GeV (131 energy points in total) with the upgraded Beijing Spectrometer (BESIII) at the Beijing Electron-Positron Collider (BEPCII), the integrated luminosities have been measured at the different c.m. energies, individually. The results are important inputs for the R value and J/ψ resonance parameter measurements.

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