Measurement of the integrated luminosity of the Phase 2 data of the Belle Ⅱ experiment

From April to July 2018,a data sample at the peak energy of the T(4 S) resonance was collected with the Belle Ⅱ detector at the SuperKEKB electron-positron collider.This is the first data sample of the Belle Ⅱ experiment.Using Bhabha and digamma events,we measure the integrated luminosity of the data sample to be(496.3±0.3±3.0) pb-1,where the first uncertainty is statistical and the second is systematic.This work provides a basis for future luminosity measurements at Belle Ⅱ.

Determination of the number of ψ' events at BES Ⅲ

The number of φ＇ events accumulated by the BESIII experiment from March 3 through April 14, 2009, is determined by counting inclusive hadronic events. The result is 106.41×（1.00±0.81%）×10^6. The error is systematic dominant; the statistical error is negligible.

Evidence for e^+e^-→γχ_(c1,2) at center-of-mass energies from 4.009 to 4.360 GeV

Using data samples collected at center-of-mass energies of √s=4.009, 4.230, 4.260, and 4.360 GeV with the BES0 detector operating at the BEPC/ collider, we perform a search for the process e＋e-→γχc,j （J =0, 1, 2） and find evidence for e＋e-→γχc1 and e＋e-→γχc2 with statistical significances of 3.0σ and 3.4σ, respectively. The Born cross sections σB（e＋e-→γχc,j）, as well as their upper limits at the 90% con dence level （C.L.） are determined at each center-of-mass energy.

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 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.