# 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.