Measurement of the integrated luminosities of the data taken by BESIII at √s=3.650 and 3.773 GeV

Data sets were collected with the BES detector at the BEPC 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 1and(2916.94±0.18±29.17) pb 1, respectively, where the first error is statistical and the second error is systematic. )