1. Mozaic trigger system for transverse momentum physics G.Vesztergombi, A.Agocs, B.Bozsogi, A.Fulop CBM Collaboration Meeting GSI – Dubna 13-18 Oct, 2008

2. Motivation for new measurements below = 20 GeV Practically no high or medium P t data between E inc = 24 and 200 GeV Mysterious transition around 80-90 GeV: convex versus concave spectra Energy threshold for Jet-quenching? Emergence of Cronin-effect in pA interactions is completely unknown energy dependence centrality dependence particle type dependence particle correlations Production of Upsilon (9.5 GeV) particles near the threshold.

3. NA49 (CERN) results at 158 FODS (IHEP) at 70 GeV Beier (1978)

4. Y production Due to high mass ( 9.5 GeV/c 2 ) two high p T particle in leptonic decay: p T > 3 GeV/c High selectivity for high p T pair even without PID

5. Benchmark NA49 pp at E = 158 GeV 30 events/spill Events Energy > 3 GeV/c > 4 GeV/c > 5 GeV/c 2 10 6 158 100 1 0.01 Estimates with the assumption 10 11 proton/sec 10 9 interaction/sec 1 day=10 14 158 5 10 9 5 10 7 5 10 5 Suppression 10 -1 10 -2 10 -3 1 day=10 14 90 5 10 8 5 10 5 500 20 day=2 10 15 90 10 10 10 7 10 4 20 day=2 10 15 45 10 7 10 0 Suppression 10 -3 10 -6 10 -10 For symmetric nuclei max energy 90/2 assumed CBM Perspectives

6. Special requirements for Y-> e+e- and high pT Extremely high intensity - Pile-up Segmented multi-target - Relaxed vertex precision Straight tracks - High momentum tracks DREAM: 10 9 interactions/sec

7. High transverse momentum means high 3-momentum Illustration for mid-rapidity at sqrt(s) 7 and 14 GeV ( ) E Lab ( ) = p long p trans 0 0 1  0  0 0 long p >= 0 Lab E >=  p trans  Beam p transLab E       

8. z [cm] x,y [cm] Px=Py = 1 GeV/c; Pz= 5 GeV/c Px=Py= 3 GeV/c Pz = 10 GeV/c High ( > 5 GeV/c ) momentum  Straight track

9. “Straight” tracks from main vertex 1-dim Hough – transform:  - histogram  N(  i ) in  bins M(  i ) = N(  i ) + N(  i+1 ) in 2  bins Correct for bin boundary crossing: Tracks with p xz > p min remains within the  p min  wedge SELECTION on p xz

10. i i+1 j j+1 3 dimensional scheme k=1 k=2 k=3 Mosaic cells in plane “k” : M(i,j,k) (i,j) Corridor contains: M(i,j,k), M(i,j+1,k), M(i+1,j,k), M(i+1,j+1,k) k=1,2,3

11. MAPS vs Hybrid Vertex resolution: dz = 1 mm, dx,dy= 0.05 mm High intensity: radiation hard Practical 4+ 2 + 3 = 9 planes ( 4 Hybrids + 5 strips) Selectivity depends on the availability of TOF information

12. s = sqrt(XX*XX+YY*YY) - delta delta Sagitta: 10-20 cm track sections are practically straight fractals (XX,YY,ZZ)  4 hybrids 2 + 3 strips 2 46Basic planes * * * * * * * * * Silicon planes

13. Basic planes: #2 = (x2,y2,z2) pixel, #4 = (x4,y4,z4) pixel, #6 = (x6,z6) strip Parallel processing: CORRIDOR # corNum Straight tracking in #2 and #4 planes in space => (mx,bx) and (my,by) Approximation: starting direction is given by (mx,my) Separate track matching in xand y for planes 5-9 Matching in #1 and #3 pixel planes in space TUBE definition: x-tube: xi = mx*(zi-z2) +bx +parabol(x6,z6,zi) +/- deltaxi y-tube: yi = my*(zi-z2) +by +/- deltayi New algorithm

14. 4-5 GeV/c pT > 1.0

15. 7-8 GeV/c pT > 1.0

16. 9-10 GeV/c pT > 1.0

17. 15-17 GeV/c pT > 2.5

18. 20-40 GeV/c pT > 2.5

19. Acceptance Npoint=9 + - pxz pT

20. Selecting only tracks with pT>2.5 GeV/c Npoint=9

21. Pileup Fixed pT-cut at 1.8GeV/c No pileup : Tracks with ptin > 1.8: 1136 ptin 1.8: 430 Npileup = 10 : Tracks with ptin > 1.8: 1136 FAKE and ptrec error : 1 + 430 Npileup = 100 : Tracks with ptin > 1.8: 1136 FAKE and ptrec error : 28 + 430 Npileup = 1000 : Tracks with ptin > 1.8: 1136 FAKE and ptrec error : 464 + 430 No LOSS of GOOD tracks due to pileup (exhaustive search!!!) Number of FAKE triggers even in 1000-fold pileup is < 50 %

22. Pileup cont. pT dependence: No pileup 1000-fold pileup  1.8 GeV/c430/1136464+430/1136  2.0 GeV/c312/704363+312/704  2.2 GeV/c208/453306+208/453  2.4 GeV/c151/301265+151/301  2.6 GeV/c103/213205+103/213  3.0 GeV/c 52/154168+ 52/154 The FAKE/GOOD ratio is moderately increasing with pT

23. Deviations within the tube dxCharge*dx

24. Y-deviations

25. Difference between exact direction and mx pT > 1.0 GeV/c pT > 2.5 GeV/c pxz

26. DAQ scheme

27. Mozaic DAQ system Two separate systems: PRETRACKING network: Pixel [#2, #4] + Strip [#6x] TRACK-QUALITY TUBE network: Pixel [ #1, #3] + Strip[#5x, #5y, #6y, #7x, #7y, #8x, #8y, #9x, #9y] In each network parallel CORRIDOR processors: CorID =corNUM Number of CORRIDOR processors: ndx*ndy Data select their routes according to plane number and corNUM In plane „zi” track-hit „xi,yi” calculates its corridor address: corNum = idx*ndy + idy

28. Corridor processors OLD system: consecutive cycling on all „planes” If only 2 points per plane: number of cycles = 2 (4+2*5) = 2 14 = 16384 NEW system: cycling only on 3 „planes” (for pixels x and y has common cycle) If only 2 points per plane: number of cycles = 2 (2+1) = 2 3 = 8 The PRETRACKING is producing a list containing: corNUM, x1,x3,x5,x7,x8,x9, y1,y3,y5,y6,y7,y8,y9 There is NO PROCESSING TIME in the TRACK-QUALITY TUBE network because It is only an ASSOCIATIVE memory which provides YES/NO. The gain in processing time (if only 2 points per plane): 2 11 = 2048-fold

29. Mozaic trigger for low pT

30. Silicon tracker in FAIR-CBM experiment Special trigger for high intensity 1O 9 interaction/sec in pp,pA reactions SIMULATION: 4 hybrid(pixel) + 5 strip = 9 silicon planes “Mosaic” front-end structure (dx,dy) regions in M(i,j,k) buffers. Exhaustive search for all tracks in (p min,p max ) corridors. TEST RESULT: 1000-fold PILEUP in pC interactions Corridor-width optimized for tracks pT > 3 GeV/c Algorithm efficiency: 100 %, with some multiple solutions picking up some random points, giving practically the same track-parameters Highly parallel algorithm is well adapted for processor clusters. Can be adapted for AA to reconstruct ALL particles with low pT corridors

31. END

32. For discussion:

33. Physical mosaic cells can be different from logical cells. Hybrid (pixel) : logical cells may be created by software Strip planes: hardware should be harmonized Corridors can be filled by hardware or software Number of processor can be less than number of corridors Corridor’s processing speed can be very fast if they are narrow Corridors can be arranged hierarchically for processing order

34. 0 0 0 1 0 0 0 0 1 0 0 1 0 0 1 0 0 2 0 0 0 3 22 5 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 4 0 48 73 44 7 1 0 0 0 1 1 0 0 0 0 1 0 0 0 0 0 34 81 90 81 35 0 0 0 0 0 0 0 1 0 1 0 0 0 0 2 28 83 92 87 89 81 25 0 1 0 2 0 1 0 0 0 1 0 0 0 17 69 93 89 91 86 87 78 16 1 1 0 0 1 0 0 0 0 0 0 4 40 86 90 90 85 91 87 86 63 13 1 0 1 0 0 1 1 0 1 1 18 72 94 91 90 89 85 87 87 83 42 9 0 1 0 1 0 0 0 0 9 52 88 90 88 85 86 93 93 91 89 77 50 8 0 0 3 0 0 1 0 28 72 88 90 90 91 85 90 86 91 90 84 80 37 0 0 0 0 0 0 8 51 74 92 92 87 91 86 91 95 90 83 93 88 75 26 0 0 0 1 1 37 62 89 87 87 88 84 85 92 96 92 91 90 90 89 Plong [GeV/c] Ptrans [GeV/c] 102030 4050 7+2 Points efficiency 2 0 4 6