Toru Iijima

10 September 2019
INT-19-74W

Abstract: Precision measurement of σ(ee → hadron) in Belle II with the ISR method will provide estimate of HVP effects, which is critical inputs to reduce uncertainty in the SM prediction (g-2)μ. The SuperKEKB/Belle II project has just started its data taking runs, and accumulated O(fb-1) data by now. The first look at early Belle II data has shown ; Clear peak of the ρ meson (π+π- mode), Also ω and φ peaks (π+π-π0 mode), Reasonable agreement between data and MC. Small efficiency loss due to Bhabha veto; ≲1% w/ new 3D Bhabha veto logic. O(100)fb-1 data expected within 1 year will provide the first result for HVP. Belle II is also possible to perform the τ → ππ0ν spectrum measurement

Note: 30 min