ITS Upgrade Simulations Andrea Dainese INFN Padova Padova

ITS Upgrade Simulations Andrea Dainese (INFN Padova) Padova, 24. 06. 13 Andrea Dainese 1

Ds: performance in central Pb-Pb with hybrid method G. M. Innocenti Statistical error on RAA and v 2 RAA 10/nb v 2 p. T Padova, 24. 06. 13 Andrea Dainese 10/nb p. T 2

B J/psi ee: performance in Pb-Pb with hybrid method Pseudo-proper decay length: Padova, 24. 06. 13 Andrea Dainese G. Bruno, F. Fionda 3

Lc p. Kp: performance in Pb-Pb with hybrid method C. Bianchin, R. Romita Result of the study on benefit of ITS PID The ITS PID has a marginal effect (~10%) on S/B and significance, and only in 2<p. T<3 Ge. V Padova, 24. 06. 13 Andrea Dainese 4

Lc with extended h acceptance C. Bianchin, R. Romita Would the HF measurements benefit of a h acc. to 1. 5 or 2? Extending from 0. 9 to 1. 5 x 2. 5 increase in signal in 2 -4 Ge. V/c However: The combinatorial background also increases Tracks outside TPC and TOF acceptance would have no PID Estimation of background now carried out Padova, 24. 06. 13 Andrea Dainese 5

Lc with extended h acceptance Signal in |h|<1. 5 with detailed PID-availability information Background scaled from |h|<0. 8 with generator-level particle combinatorics, with two cases of PID-availability: All tracks with PID (better than real situation) + 30 -50% for S/B and Signif All tracks without PID (worse than real situation) - 20 -60% for S/B and Signif Current conclusion: no strong benefit of extended h for the low-p. T HF analyses that use PID heavily Padova, 24. 06. 13 Andrea Dainese 6

Low-mass dielectrons P. Reichelt Completed study on benefit of ITS PID Full analysis in three cases Ideal PID in ITS (as for CDR) Realistic PID in ITS (assuming new ITS PID = curr ITS PID) No PID in new ITS Reminder: Di-electron pair kept for analysis: both electrons ID in TPC+TOF Before making electrons pairs: rejection of electrons from g conversions Ø All TPC+TOF electrons that make a conv-like pair with another track, also ITS standalone here is the role of ITS PID Padova, 24. 06. 13 Andrea Dainese 7

Low-mass dielectrons P. Reichelt Significance decreases by 10 -20% without PID Padova, 24. 06. 13 Andrea Dainese 8

Low-mass dielectrons P. Reichelt Padova, 24. 06. 13 Andrea Dainese 9

Low-mass dielectrons P. Reichelt High-mass slope (“T”) v 2 “Temperature fit”: Stat. err. +20% without PID Syst. err. +50% without PID Padova, 24. 06. 13 Dielectron v 2: Stat. err. +10% without PID Andrea Dainese 10

Preparation of full simulation Requests approved by Physics Board: 1 M events Cocktail: Hijing 0 -10% 5. 5 Te. V + HF and hypernuclei signals Ø Very similar to LHC 12 a 17 a (except for the energy) Estimated resources (extr. from the similar LHC 12 c 4): Ø 300 CPU y ( ~10 days with 10 k jobs) Ø 100 TB (with AODs) Generator settings have been defined ITSU code (close to) ready AOD-filtering settings finalized Need Ali. Root release + testing + prioritization + running Estimated time: at least 3 weeks Padova, 24. 06. 13 Andrea Dainese 11

ITS upgrade simulation Padova, 24. 06. 13 Andrea Dainese 12

Tracking performance with full simulation Tracking efficiency is ok drop at 500 Me. V issue in geometry, fixed today Padova, 24. 06. 13 Andrea Dainese 13

Tracking performance with full simulation Impact parameter resolution matches CDR estimates CDR (analytic) Full Sim Padova, 24. 06. 13 Andrea Dainese 14

Physics Performance in TDR: chapter outline Chapter editors: A. Dainese, G. Usai Introduction Very short reminder of main motivations of the ALICE upgrade (cfr LOI 1. 2) Running scenario and expected yields Running/trigger strategy, assumed rates and stats (cfr LOI 1. 4, CDR 2. 3. 1) Simulation methods and conditions Hydrid (cfr CDR 2. 3. 2) and full simulation (cfr TDR ch 7) Heavy flavour Motivation D mesons (full sim): D 0, Ds, D* Beauty: B D 0, B D 0 p, B D*, B Jpsi ee Baryons: Lc (including discussion on PID) and Lb Jets: jet-D correlations and b-tagging (tbc) Legend: ~ Ready Results ready, no text Some results are there Working on analysis Low mass dielectrons Motivation Performance and PID discussion Multi-particle correlations Hyper-nuclei Padova, 24. 06. 13 Andrea Dainese 15

Conclusions Good progress on all fronts Benefit of PID in new ITS: Marginal for low p. T Lc Marginal for di-electron statistical errors, but reduces systematic error from 30% to 20% Benefit of extended h acceptance: Marginal for low p. T HF Clear for multi-part corr. , but could be not the only way, and could be not unique (to be continued) New results ~ready for TDR (at least as plan B): D*, Ds, B J/y, Lc Need full MC: D 0, B Dp, Lb, hyper-nuclei Padova, 24. 06. 13 Andrea Dainese 16