ITS offline Massimo Masera Torino Open savannah bugs

ITS offline Massimo Masera Torino

Open savannah bugs 2 Bug # Description Assigned to Comment 47410 Improvements in the standalone ITS tracker: taking into account the energy losses, possibility to start from the outer. Francesco Prino We propose to close it 47413 Correct treatment (in both cluster- and track finders) of the SSD modules that are dead on one side A. Dainese Problem: negative diagonal cov. matrix 57776 Negative eigenvalues of the track covariance matrix in Ali. ITStrack. V 2: : Improve Jouri Belikov Ali. ITStrack. V 2: : Improv e disabled for p-p, but it will be needed for Pb-Pb 60032 reworked SSD clusterfinder Enrico Fragiacomo merging HLT and SSD clusterfinders Domenico Elia 15/3/2010 merging HLT and SPD clusterfinders ITS offlinereworked SPD clusterfinder 60081

Open savannah bugs 3 Bug # Description 62312 Ali. Multiplicity does not contain Domenico labels for single clusters Elia labels of unassociated clusters on Layer 1 should be added to add correction factors from MC 63719 Request to update the OCDB by new ITS alignment and respone. SDD object New SDD Vdrift and t 0 correction. The task can be closed. 63965 Detail study of material budget Massimo in simulation/ comparison to Masera data Possible missing material in the ITS layers. Under investigation 63966 Propagate function in Ali. ITSV 0 Finder Mass shift in K 0 S reported by Ana Marin, who is 15/3/2010 checking material ITS offline Assigned to Comment Raffaele Grosso Marian Ivanov

Material budget Savannah bug 63965 Friederike Bock http: //indico. cern. ch/conference. Di splay. py? conf. Id=87158 and http: //indico. cern. ch/conference. Di splay. py? conf. Id=87662 • Usage of 2 different V 0 finders to check sysyematics • In ITS it seems that material budget is underestimated • Major differences around Z=0 4 ITS offline 15/3/2010

Material budget 5 Beam pipe + SPD SDD 1 SDD 2 SSD ITS offline F. Bock March, 5 -th 15/3/2010

Planning tool/1 6 Tas k Title User Deadline Comment 258 1 Implementation of a detailed description of the cables and services outide the ITS cones M. Sitta 31/01/201 0 Implemented side A services (rev 39604) 258 2 Improvement of the description of the forward services M. Sitta 31/01/201 0 Duplicate of the previous 258 3 Implementation of full misalignment without overlaps Grosso, 01/03/201 Dainese, 0 Sitta Real SPD geometry different from ideal new geo. ready to be checked with alignment 259 0 Verification of the event merging procedures M. 02/04/201 Poghosy 0 an Bugs found and fixed (rev. 38956 and 39464). Further 15/3/2010 checks with SSD ITS offline

Planning tool/2 Tas k Title User Deadline Comment 260 4 Implementation of simulation in QA checker Panos, Melinda, Mariella 30/04/201 0 (*) Checker for QA task k. SIM exists only for SDD 260 5 Implementation of reconstruction in QA checker Panos, Melinda, Mariella 01/04/201 0 (*) Various degrees of implementation for the 3 subsystems 260 6 Implementation of reference data Panos, Melinda, Mariella 30/06/201 0 Not foreseen for the moment 264 9 Extract QA data from large Monte Carlo production Panos, Melinda, Mariella 15/08/200 9 To be removed 267 9 7 SDD alignable objects from M. 11/06/201 survey used in sim/rec Poghosy 0 ITS offline an 15/3/2010

ITS alignment & tracking (Slides from A. Dainese)

Alignment used for 2009 pp data: as of JINST paper SPD alignment with cosmics 2008 (B=0), with Millepede Ø few modules on the sides “corrected” with pp data (see later) SSD internal alignment from survey only (validated) SPD-to-SSD alignment with Millepede ITS-to-TPC alignment with cosmics + pp 2009 (Marian, Mikolaj) In progress: use pp data (B-on, B-off) to complete the alignment with Millepede 2 (Ruben) Ø minimal alignment of the SPD side modules not covered by cosmics (~10% of SPD) Ø SDD calibration and alignment (see Francesco’s talk) Ø improvement of the full SPD, then SSD ladders estimate of alignment / tracking precision with Ø extra clusters in module overlaps Ø cosmics B-on (Feb-2010 not yet properly reconstructed) ITS offline 9

Alignment data filtering Ali. Track. Points extracted from ESDs+ESfriends (pass 2) Task PWG 1/ITS/Ali. Alignment. Data. Filter. ITS extracts to a tree the ITS Ali. Track. Points for selected tracks also stored: Ø curvature and error from full track (ITS+TPC) Ø run number, B value Ø path of OCDB files for ITS alignment and calibration used in reco – needed by Millepede to get initial geometry conditions Should become a task of the “ 2 nd step calibration train” All good runs processed (from run coord table) 430, 000 events B=0. 5 T 100, 000 events B=0 (430, 000 tracks) All points are in /alice/cern. ch/user/d/dainesea/ITSpoints/ ~0. 5 GB ITS offline 10

SPD alignment with pp sides Ruben ITS offline 11

Track rf impact parameter pt=1. 0 -1. 5 Ge. V data MC ITS offline PASS 1 cosmics only cosmics + pp (f=0 and p) PASS 4 12

Simulate with “data” geometry Alignment results suggest that the real SPD geometry differs from the design (and Ali. Root) one by a few 100 mm in some places (shape of carbon fiber sectors) Many large TGeo overlaps. . . Raffaele ITS offline 13

Simulate with “data” geometry Removing overlaps goes in parallel with understanding alignment geometry could be changed once we are fully confident on alignment there is a task (2583) related to changing the SPD geometry to make it "overlap free" after alignment: a new ideal geometry with the sensitive volumes (ladders) in the same place where put by alignment has been already produced behaviour w. r. t. alignment still under investigation ITS offline 14

ITS tracking In order to maximize tracking efficiency (TPC-to-ITS prolongation efficiency): assigned large “misalignment” errors to ITS clusters 100 mm for SPD, 1 mm for SDD and SSD Also limits the track precision, but this is not critical for the currect analyses ITS+TPC tracks being used in all papers in preparation ITS offline 15

TPC-ITS prolongation Data (104892) pass 4 MC LHC 10 a 8 16 Track selection: ncls. TPC>90, c 2/cl<4, TPC ell. dca (2. 4 cm x 3. 2 cm), |h|<0. 8 ITS offline 16

TPC-ITS prolongation: Data Eff / MC Eff Data (104892) pass 4 MC LHC 10 a 8 PYTHIA condition used in ongoing analyses Possible reasons for the discrepancy: - ITS detector status (dead/noisy channels) not the same detailed checks in MC and data ongoing in subdets. - misalignment and miscalibration - larger fraction of secondaries in the data than in MC ITS offline 17

Transverse impact parameter resolution from data Methods: top-bottom matching vs pt with cosmics (need 2010 cosmics) fit central part of inclusive d 0 distribution in pp Ø need to deconvolute vertex resolution use statistical estimators in pp Ø intrisically disentangles track Ø and vertex resolution ITS offline 18