# 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