Status FTKSIM July 20 2005 G Volpi Siena

Status FTKSIM July 20, 2005 G. Volpi (Siena) for: F. Crescioli, M. Dell'Orso, G. Punzi, C. Roda, G. Usai, I. Vivarelli, G. Volpi.

Code organization In progress Existing (SVT) Red: basic performance parameters than can be brought inside ATLFAST

Status FTKSIM ● ● Now we have approximately 1300 K events of single muon track monochromatic in Pt (at 6, 8, 10, 20, 40 Ge. V/c) Event digitization without noise and secondary propagation off. Sufficient statistic to divide barrel in sectors (R-phi plane), geometrical constants and patterns for each sector. Test some performance of linear fit vs ATLAS full offline reconstruction, using Space Points (SP).

Sectors ● ● ● Barrel divided in 355 sectors in tranverse plane. Each sector consists of a combination 6 silicon module, 1 silicon module per layer. sub-sample of 350 k tracks of mu+ and mu-, Pt = 6, 8, 10, 20 , 40, to generate linear constants. Usable for geometrical generation: 289 k tracks Linear constants for 348 sectors (all but the lowest populated ones)

Performance on tracks ● ● We have determined linearized fit constants (. fcon for CDF people) for transverse track parameters 1/Pt, phi and impact parameter. We made a comparison of ATLAS reconstruction (R) and linearized fit (F)

Curvature reconstruction FTKSIM evaluates curvature correctly, with a resolution only slightly worse than ATLAS reconstruction algorithm (i. Pat. Rec)

Same small biases are present both in offline reconstruction and ftksim UNDER INVESTIGATION

Curvature reconstruction show a small non-linearity ●Resolution on 1/Pt vs 1/Pt is worse than i. Pat. Rec by nearly constant offset ● i. Pat. Rec shows a bias on reconstruction of Pt.

Phi reconstruction FTK reconstructs phi of tracks with same precision of ATLAS algorithm

FTKSIM reproduces also a strange periodic pattern in phi difference vs global phi. i. Patrec

Impact parameter fit Impact parameter reconstructed by FTKSIM appears to be better than Off-line. Not an actual performance because FTK in this case forces fits to have <d>=0 mm, while ATLAS reconstruction don't: Impact parameter currently underestimated

Summary and next steps ● ● We have successfully determined linearized constants for measuring phi and Pt in silicon tracker. We still need to improve a few things. However, our first priority now is to produce and distribute a first release of a package that anybody can use to start physics studies with FTKSIM

Detailed physics studies

Parallel work, of lower priority ● ● ● Start studies on use of the 2 nd local coordinate z, to extract z 0 and cot(theta) parameters. We need a sample of single tracks coming from a larger beam spot, in order to fit impact parameter correctly. We need a continuous Pt spectrum, rather than discrete values in order to produce realistic patterns. – ● The above two things probably cannot be done with current samples, and we have to make the effort of generating it ourselves. Try to get better linarity in 1/Pt with a higher granularity of sectors.