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Title: Measurement of the e +e -→π +π - cross section between 600 and 900 MeV using initial state radiation

We extract the e +e -→π +π - cross section in the energy range between 600 and 900 MeV, exploiting the method of initial state radiation. A data set with an integrated luminosity of 2.93 fb -1 taken at a center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII collider is used. The cross section is measured with a systematic uncertainty of 0.9%. We extract the pion form factor |F π| 2 as well as the contribution of the measured cross section to the leading-order hadronic vacuum polarization contribution to (g-2) μ. In conclusion, we find this value to be a π μ π,LO (600–900 MeV) = (368.2 ±2.5 stat±3.3 sys) ·10 -10, which is between the corresponding values using the BaBar or KLOE data.
  1. et. al.
Publication Date:
Grant/Contract Number:
FG02-04ER41291; FG02-05ER41374; FG02- 94ER40823; SC0010118; FG02-94ER40823; DESC0010118
Published Article
Journal Name:
Physics Letters. Section B
Additional Journal Information:
Journal Volume: 753; Journal Issue: C; Journal ID: ISSN 0370-2693
Research Org:
Indiana Univ., Bloomington, IN (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Hadronic cross section; Muon anomaly; Initial state radiation; Pion form factor; BESIII
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1242353