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# System prepended metadata

title: 'Physics Performance Meeting, 25.11.2020'

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# Physics Performance Meeting, 25.11.2020

Slides: https://indico.belle2.org/event/3264/

## Feedback from WG1 (Racha Cheaib)

 * $\chi_d$ measurement with SL double tagged events
     * charge asymmetries in run-independent MC (MC13a), much better agreeement for run-dependent MC (MC13b)
 * untagged $B\to X\ell\nu$
     * small discrepancies for muons between data and run-indepedent MC

#### Questions and Comments

* Umberto: If you "flip" the charges, is everything else the same?
 
  > Racha: Differences in track multiplicities are expected, differences between data and MC not.
  
* Ami: How close are the two tracks? Asymmetries are seen in tau studies.
  > Racha: Not studied yet, we will make plots for this.

 * Torben: beam spot in MC13a is not optimal: much better agreement for MC13b is expected.
 * Martin: MC14a will also have the correct beam spot.


## Feedback from Tau WG (Michel Hernandez Villanueva)
 * What are the systematics uncertainties for the beam energies?
 * Need corrected B-field map
 * We corrections for modified PID (i.e. using different priors) and/or endcaps be provided?
 * What are the recommendations for pi0/photon timing?
 * How to handle FSR and ISR corrections?

#### Questions and Comments

 * Jim: Stat.+ Syst. uncertainties for beam energies (B mass is included already) and linearity check (using MC) is underway. Moriond timeline is realistic.
 
 * Torben: What does "free parameter" of the scale factor mean?
     > It means that the correction should depend on momentum and theta.

 * Ami: Angelo promised to provide corrections and systematics for whatever HID combination we use.
 * Racha: What is the momentum range of the pions?
    > Not too soft, the tau moementum is about 3.5 GeV.
 * Umberto: Pion ID is bad if you only have CDC information, especially also charge asymmetries.
 * Petar: Most discrepancies may disappear once all corrections are applied.
 ** Will be followed up offline.

 * Torben: FSR recommendation: Use the available tools and see if agreement improves. ISR is generally analysis-dependent, not clear what general recommendations can be given at this level.

 * Koga-san: 2D and 3D improvements for track triggers will provide better effciency in the endcaps for "short tracks". NN allone will not help much.

## Updated B-Field (Thanh Dong)

 * Calculated and "rescaled_V2" map (from measurements) exist
 * rescaled_V2 is smoothed, and then adjusted in regions > 96cm
 * Outer regions (TOP, ECL) in barrel are not measured but only extrapolated
 * Calculated B field in BWD abd FWD and outer regions is scaled


#### Questions

 * Will this be used for MC14?
   >  Martin: No, but since MC14 is self-consistent (same field used in simulation and reconstruction) This should not be very relevant. It should be ready for proc12.

 * Has the track-cluster matching for ECL and KLM been evaluated yet?
   > We will ask experts from these subdetectors to check that performance once we have the corresponding MC samples.