Computing EVO meeting, January 15 th 2013 Status of the Tracking Code

1. Computing EVO meeting, January 15th 2013 Statusof the Tracking Code Gianluigi Boca, Pavia University

2. Progress on the online Pattern Recognition YutieLiang, December meeting Results on multitrackevent, no Mixing for the moment; Determinationof the Radius ( = Pof the track) and center ofHelix : conformaltransformationfor the Sttdriftcircles; useof the tangentsto the driftcirclestofill the Hough plot ; 2) adaptiveHoughtransformmethod ; 3) inclusionof the Mvdhits; Presolution = 3.1 % at 1 GeV/c at the PR level

3. Adaptive Hough transformation Initially, 16 X 16 Hough space, keep the best 16 bins for the next step. For a peak(r, θ), locate the area of r-2 ~ r+1, θ-2 ~ θ+1 Divide the area into 16 X 16 Hough space. (equivalent to 64 X 64 ) Iteration 0 1 2 3 4 5 Hough space 16X16 64X64 256X256 1024X1024 4096X4096 16384X16384

4. Inclusion of MVD Y(cm) MVD Points Belong to MVD points Pt resolution @ 1GeV/c Iteration: 4 5 6 STT: 3.2% 3.2% 3.1% STT+MVD : 3.3% 3.2% 3.1% No improvement on the pt resolution! X(cm)

5. Progress on offline Pattern Recognition (present status, Gianluigi) At the last collaboration meeting itwasshownthat the Cpu times on an Intel Xeon 2.13 GHz 64 bit Lenny computer was ~ 1 sec/evtwith the event mixing. Thatwasachievedbysubstituting the slow iterative fittingmethods (GLPK) with muchfaster ‘analytical’ methods ( minimum 2 formula) or Houghtransform methods.

6. Roadmap : The CpuTimestillneed and can beimprovedbychanging the way the trackcandidates are foundwith the ‘road’ methods : a) useasseedonlyhits in the axialStt at the boundaryof the detector; b) confirmtrackwith a SciTil hit at the earliestpossible stage ; c) rejectghosttrackswith ‘holes’ at the earlierpossible stage (cleanup); d) parallelize the code. DONE ! Presentresultnext week at the Pattern Recognition EVO.

7. Change the way the cluster search in XY planeisperformed Improvement : onlySttaxialhits on the geometricalboundaryof the axialSttregion are consideredaspossible cluster seed. 13 times MC truth Mvd Pixel reco track Mvd Strip Stt Parallel SciTil

8. Progress on ForwardStraw Pattern Recognition (December meeting, Martin) a) Parabola approximation in ZX plane, inside dipole plus straightlinesoutside; b) parametersof parabola foundwithHoughTransformmethod; c) so far implemented the non-skewStraw part of the algorithm, taking the drift circlesinto account;

9. New ideasfor the online STT pattern recognition (December meeting, Marius) Triplet Finding in Axial Straws • Oncetwotripletsarefound, calculatecirclethroughorigin • Associatenearbyhitswithtrackcandidate • Track Verification: • Currently mix ofcurvatureandassociatedhits • Lots ofroomforimprovement • Further possibilites: • Distancesorting, Concurrentassociations, Clutterveto, … • Missingstrawcompensation: Pivot Strawtriggeredbyneighborstraws • Weighthitsaccordingtotimestamp • Improved Triplet merging Interaction Point Marius C. Mertens

10. Progress on the SecondaryTrackFinder and relatedissues (present status, Lia) a) applicationof the Legendretransform in the searchof the secondaryvertices (work in progress); b) structureto integrate the primary and secondarytrackfinder; newmethodtoidentify the neighbouringstrawof a givenSttaxial tube ; thistoolisusefulboth in the cluster finding and in the cleanup code

11. New functionsfor STT Parametrization of thegeometrylimitingtubes… … inordertoassigntoeach tube alayerID and asectorID III. Toolfor STT • LAYERS • SECTORS L. Lavezzi