Impact of Misalignment on J/ y Mass (A First Look)

1. Impact of Misalignment onJ/y Mass(A First Look) Steven Blusk Syracuse University

2. Introduction • We will have a lot of J/y’s to use to monitor the alignment. • Potentially, they could also be used in the alignment itself, once all the magnetic field issues are understood. • Here, I present first look at the effects on the J/y mass as a function of the detector misalignments • Will give an idea what level of misalignments we will be sensitive to • This is just a first look. There’s a lot more to do. • See summary

3. Software Details • Gauss v25r10 – Both B and B J/ynn. • Only run B’s through detector simulation •  Clean J/y signal sample with reasonable momentum spectrum as we’ll have in data. • Brunel v31r5 • Reconstruct with default CondDB (tag = “DC06”)

4. Techniques (1) • Misalign each independently, and for each create a new CondDB. • For each one, we smear the translational & rotational misalignments by an 1s, 2s, 10s, 25s, 50s, 100s. • Here, s is an ‘educated guess’ of the alignment precision after full software alignment. • Detector-dependent and different for each misalignment (TX, TY, TZ, RX, RY, RZ) • In some cases it came from alignment studies (VELO), and for T-Stations it was a best guess. • I only do “1 simulated experiment” per misalignment scenario

5. Techniques (2) • “J/y”DSTs are read in with the misaligned CondDB’s • Read DST to get nominal track momenta (BEST-Long) • Then, refit the track using smeared hit positions • We DO NOT re-run pattern recognition. • Run MUON PID to select tracks that would be ID-edby the muon system • Compute invariant mass of all m+m- pairs • Will look at a series of plots, with each misalignmentstudied by itself.

6. Velo Misalignments y • Detector half level • Left misaligned by +1s • Right misaligned by -1s • Module level • Sensor Level • f sensors only Rotations & translations around the shown axes z x

7. X1 U ------ V X2 OT Misalignments • Profile of a single station • 8 measuring planes/stat. • U/V are +5/-5 stereo wrtvertical. • X1&U // V&X2 onseparate trolleys • Left/right half roll in/outindependently • Misalignments applied: • System – all 3stations together • Station – each stationindependently misaligned • Half-Station – X1&U, V&X2left, right misaligned indep. • Modules – each modulemisaligned • Layers – each layer misaligned

8. IT Misalignments 1 IT Station • Misalignments applied: • System • Station • Box Layers • Layers • Ladders

9. Velo Half-Box Misalignment Mass distributions for different levels of misalignment Yield in peak region vs #sigma Note: Velo slope resolution~0.2 mrad~10s (for Rx) 3.14 GeV 3.05GeV

10. Velo Module Misalignment

11. Velo f Sensor Misalignment

12. IT System Misalignment All tracks considered here,not just IT tracks

13. IT Station Misalignment

14. IT Box Misalignment

15. IT Layer Misalignment

16. IT Ladder Misalignment

17. OT System Misalignment

18. OT Station Misalignment

19. OT Module Misalignment

20. OT Layer Misalignment

21. Summary • First look at effects on J/y mass with CondDB misalignment infrastructure • Tools developed to facilitate this • In all cases, mass resolution affected minimally, if detector misalignments are randomly distributed with values  few s. • J/y mass may not help to improve alignment (mass constrainedalignment fit) • Lots to do and lots can be done now • Need to confirm that these “s”-s are “reasonably achievable” by software alignment (adjust as necessary & repeat) • Study correlated misalignments • Implement some code to investigate TT • Study momentum resolution in each case. • Look at separation in B & BsKp. • Do multiple misalignment sets at each value of “s”