First measurements of charged particle multiplicity in p-p collisions at the LHC with the ALICE experiment

Massimo MaseraTorinoITS offlineOpen savannah bugs15/3/2010ITS offlineBug #DescriptionAssigned toComment 47410Improvements in the stand-alone ITS tracker: taking into account the energy losses, possibility to start from the outer.Francesco Prino We propose to close it47413Correct treatment (in both cluster- and track finders) of the SSD modules that are dead on one sideA. DaineseProblem: negative diagonal cov. matrix57776Negative eigenvalues of the track covariance matrix in AliITStrackV2::ImproveJouri BelikovAliITStrackV2::Improve disabled for p-p, but it will be needed for Pb-Pb60032 reworked SSD clusterfinderEnrico Fragiacomomerging HLT and SSD clusterfinders60081reworked SPD clusterfinderDomenico Eliamerging HLT and SPD clusterfinders2Open savannah bugs15/3/2010ITS offlineBug #DescriptionAssigned toComment 62312 AliMultiplicity does not contain labels for single clusters Domenico Elia labels of unassociated clusters on Layer1 should be added to add correction factors from MC 63719Request to update the OCDB by new ITS alignment and responeSDD objectRaffaele Grosso New SDD Vdrift and t0 correction. The task can be closed.63965Detail study of material budget in simulation/ comparison to dataMassimo MaseraPossible missing material in the ITS layers. Under investigation63966Propagate function in AliITSV0FinderMarian IvanovMass shift in K0S reported by Ana Marin, who is checking material budget correction 64054Request for new reconstruction pass (pass6) of 900 GeV dataYves SchutzDepends on bug # 637193Material budget15/3/2010ITS offlineSavannah bug 63965 FriederikeBock http://indico.cern.ch/conferenceDisplay.py?confId=87158 andhttp://indico.cern.ch/conferenceDisplay.py?confId=87662 Usage of 2 different V0 finders to check sysyematics In ITS it seems that material budget is underestimated Major differences around Z=0

4Material budget15/3/2010ITS offline

F. Bock March, 5-thBeam pipe + SPDSDD1SDD2SSD5Planning tool/115/3/2010ITS offlineTaskTitleUserDeadlineComment2581Implementation of a detailed description of the cables and services outide the ITS cones M. Sitta31/01/2010Implemented side A services (rev 39604)2582Improvement of the description of the forward servicesM. Sitta31/01/2010

Duplicate of the previous2583Implementation of full misalignment without overlapsGrosso, Dainese, Sitta01/03/2010Real SPD geometry different from ideal new geo. ready to be checked with alignment 2590Verification of the event merging procedures M. Poghosyan02/04/2010Bugs found and fixed (rev. 38956 and 39464). Further checks with SSD2592Verification of the embedding procedures M. Poghosyan02/04/2010See task 25906Planning tool/215/3/2010ITS offlineTaskTitleUserDeadlineComment2604Implementation of simulation in QA checker Panos, Melinda, Mariella30/04/2010 (*)Checker for QA task kSIM exists only for SDD2605Implementation of reconstruction in QA checkerPanos, Melinda, Mariella01/04/2010 (*)Various degrees of implementation for the 3 subsystems2606Implementation of reference data Panos, Melinda, Mariella30/06/2010Not foreseen for the moment2649Extract QA data from large Monte Carlo production Panos, Melinda, Mariella15/08/2009To be removed2679SDD alignable objects from survey used in sim/rec M. Poghosyan11/06/20107ITS alignment & tracking(Slides from A. Dainese)8AlignmentAlignment used for 2009 pp data: as of JINST paperSPD alignment with cosmics 2008 (B=0), with Millepede few modules on the sides corrected with pp data (see later)SSD internal alignment from survey only (validated)SPD-to-SSD alignment with MillepedeITS-to-TPC alignment with cosmics + pp 2009 (Marian, Mikolaj)In progress:use pp data (B-on, B-off) to complete the alignment with Millepede2 (Ruben)minimal alignment of the SPD side modules not covered by cosmics (~10% of SPD)SDD calibration and alignment (see Francescos talk)improvement of the full SPD, then SSD laddersestimate of alignment / tracking precision withextra clusters in module overlapscosmics B-on (Feb-2010 not yet properly reconstructed)ITS offline9Alignment data filteringAliTrackPoints extracted from ESDs+ESfriends (pass2)Task PWG1/ITS/AliAlignmentDataFilterITSextracts to a tree the ITS AliTrackPoints for selected tracks also stored:curvature and error from full track (ITS+TPC)run number, B valuepath of OCDB files for ITS alignment and calibration used in reconeeded by Millepede to get initial geometry conditionsShould become a task of the 2nd step calibration trainAll good runs processed (from run coord table)430,000 events B=0.5T100,000 events B=0 (430,000 tracks)All points are in /alice/cern.ch/user/d/dainesea/ITSpoints/~0.5 GBITS offline10SPD alignment with pp

ITS offline11

RubensidesTrack rf impact parameter pt=1.0-1.5 GeVITS offline12PASS1PASS4

cosmics onlycosmics + pp (f=0 and p)dataMC

dataMCSimulate with data geometryAlignment results suggest that the real SPD geometry differs from the design (and AliRoot) one by a few 100 mm in some places (shape of carbon fiber sectors) ITS offline13

Many large TGeo overlaps...RaffaeleSimulate with data geometryRemoving overlaps goes in parallel with understanding alignment geometry could be changed once we are fully confident on alignmentthere 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 producedbehaviour w.r.t. alignment still under investigationITS offline14ITS trackingIn order to maximize tracking efficiency (TPC-to-ITS prolongation efficiency): assigned large misalignment errors to ITS clusters100 mm for SPD, 1 mm for SDD and SSDAlso limits the track precision, but this is not critical for the currect analysesITS+TPC tracks being used in all papers in preparation ITS offline15TPC-ITS prolongationITS offline16Track selection: nclsTPC>90, c2/cl