1. Pixel resolution, impact parameter resolution and b-tagging calibrations Attilio Andreazza, Christian Schmitt, Sara Strandberg, Christian Weiser

2. Pdf calibrations Impact parameter significance depends on three length scales 1.Tracking parameterization of detector resolution 2. b (and c) quark decay lengths 3.Real detector resolution (and material) All three should match between data and MC: 1.By construction 2.Let’s hope to have the physics right! 3.Not implemented yet 2 CERN, 9 August 2011 A. Andreazza, IP resolution meeting introduction Heather 2/1 3/1 Giacinto

3. What to do? No modification in reconstruction for initial MC11 campaign: –Only AODcalib approach available (no track refit) –Smearing IP is possible (we have already the data the MC needs to reproduce) Need to accelerate a lot if wanting to use it on first D3PD from MC11 For next reconstruction campaign (Xmas?) –Why such a large error scaling? Intrinsic detector resolution? (Vicente’s overlaps studies…) Residual mis-alignment (shaken DB: Anthony?) Error scaling procedure (try it on MC: ?) –Implement “smearing” on points: alignment+pixel software groups? –Need granularity to be improved? How? Should be bind error scaling with smearing? i.e. at the same time error scaling is computed, it is also used to provide smearing factors to be applied during release validation and b-tagging calibrations Will it remove the need of core IP smearing? Will it make possible data/MC comparison during validation CERN, 9 August 2011 3 A. Andreazza, IP resolution meeting introduction