---
# System prepended metadata

title: 'Physics Performance Meeting, September 2nd, 18:00 JST'

---

# Physics Performance Meeting, September 2nd, 18:00 JST

Slides: https://indico.belle2.org/event/2567/

## ee->eell (Yo Sato)
 * pro: large statistics (stat. unc. <0.1% per bin), wide momentum range
 * contra: sensitive to L1 triggers
 * ICHEP results based on MC13a and proc11
 * Trigger problems: 
     * Short track triggers (fsb, ssb) are not available in MC13a which effects endcap regions
     * bhabha veto different which effects high momentum region
     * TSIM between MC12 and MC13a is different, investigation is ongoing
 * HLT skim for autumn run is ready
 * Systematics:
     * dominant: ee->eehh has a 10% uncertainty, results in O(0.1%) uncertainty, might be reduced by using lepton-ID with BDT
     * fake-rate ratio also O(0.1%)
         * pion/lepton is statistics limited
         * muon/electron will be evaluated in low-p region
     * 

#### Questions

* Karim: How will the new MC improve the high momentum region?
  > TSIM bhabha veto condition is updated in new version.
* Torben: With such a small uncertainty, eell must dominate?
  > We inflate the uncertainties if different methods disagree. This is the dominating effect for the large uncertainties on page 3.
* Bruce: Can one extend/change the momentum binning (100 MeV very low, 500 MeV above)?
  > The discrepancies are 1-2sigma, so nothing dramatic. Fake rates are more different.
  > J/Psi has very few events below 1 GeV, so the deviation is really not too much.
 * Alberto: Any updates on CDC dE/dx for electron fake rate?
      > Nothing for now, maybe with the next processing/MC
 * Philip: https://indico.belle2.org/event/2506/contributions/12299/attachments/6358/9864/LeptonID_validation.pdf