1. Ronen Ingbir Collaboration High precision design Tel Aviv University HEP Experimental Group Krakow2006

2. Events (rad) Collaboration High precision design Krakow2006 Energy (GeV) Events Bhabha Scattering Tel Aviv University HEP Experimental Group

3. Collaboration High precision design Krakow2006 Bhabha Scattering Head-on (rad) X (cm) Y (cm) Events Tel Aviv University HEP Experimental Group

4. Collaboration High precision design Krakow2006 (rad) X (cm) Y (cm) Events Bhabha Scattering 20mrad X-angle Detector axis Tel Aviv University HEP Experimental Group

5. Collaboration High precision design Krakow2006 (rad) X (cm) Y (cm) Events Bhabha Scattering 20mrad X-angle Outgoing beam Tel Aviv University HEP Experimental Group

6. Collaboration High precision design Krakow2006 (rad) X (cm) Y (cm) Events (rad) Events X (cm) Y (cm) Outgoing beam  flat azimuthal distribution Tel Aviv University HEP Experimental Group

7. N 1 : Reconstructed and generated in acceptance region. N 2 : Generated in acceptance region but reconstructed outside. N 3 : Generated outside acceptance region but reconstructed inside. Collaboration High precision design Luminosity precision determination Krakow2006 Tel Aviv University HEP Experimental Group

8. Collaboration High precision design Krakow2006 No Yes Counting Bhabha events MaxMin ~25 cm~10 cmR 80 mrad33 mradθ Tel Aviv University HEP Experimental Group

9. Collaboration High precision design Krakow2006 Headon, 14,20 mrad X-angle outgoing beam 14 mrad X-angle detector axis 20 mrad X-angle detector axis Tel Aviv University HEP Experimental Group

10. Collaboration High precision design Krakow2006 Headon, 14,20 mrad X-angle outgoing beam 14 mrad X-angle detector axis 20 mrad X-angle detector axis ΔzΔz Tel Aviv University HEP Experimental Group

11. Collaboration High precision design Krakow2006 Tel Aviv University HEP Experimental Group Δr Δz ΔzΔz ΔrΔr Bhabha Scattering Outgoing beam ΔL/L=10 -4

12. Collaboration High precision design Krakow2006 Headon, 14,20 mrad X-angle outgoing beam 14 mrad X-angle detector axis 20 mrad X-angle detector axis Tel Aviv University HEP Experimental Group

13. Collaboration High precision design Krakow2006 Headon, 14,20 mrad X-angle outgoing beam 14 mrad X-angle detector axis 20 mrad X-angle detector axis Tel Aviv University HEP Experimental Group

14. Collaboration High precision design Krakow2006 1.Bhabha events sample will not be pure (background). 2.Magnetic field changes the distribution (could be a dramatic effect if not aligned with the outgoing beam). 3.Event position and energy reconstruction is not perfect. 4.To evaluate the real error on luminosity one should apply MC – DATA corrections. Are these numbers realistic ?    Tel Aviv University HEP Experimental Group

15. X- angle background Collaboration High precision design Christian Grah, DESY-Zuethen Beamstrahlung pair background 250 GeV Krakow2006 Tel Aviv University HEP Experimental Group 20 mrad, DID 20 mrad, anti DID

16. Collaboration High precision design Krakow2006 Magnetic field along the outgoing beam Tel Aviv University HEP Experimental Group

17. Fast detector simulation – bias Changing the bias with a fixed resolution. Collaboration High precision design Krakow2006 Tel Aviv University HEP Experimental Group

18. Changing the detector resolution with no bias Collaboration High precision design Krakow2006 Fast detector simulation – resolution Tel Aviv University HEP Experimental Group

19. Collaboration High precision design Krakow2006 How does the LumiCal performance contribute to the detector displacements ? Tel Aviv University HEP Experimental Group

20. Collaboration High precision design Krakow2006 Tel Aviv University HEP Experimental Group Adding detector performance Using bias and resolution of Pad design LumiCal without Including

21. Collaboration High precision design Krakow2006 Tel Aviv University HEP Experimental Group Adding detector performance Using bias and resolution of Pad design LumiCal without Including

22. Data and MC In real life we can include the detector performance (which is measured in test beam) into MC. The only question is: How well should we know the detector performance ? Collaboration High precision design Krakow2006 Tel Aviv University HEP Experimental Group

23. Collaboration High precision design Krakow2006 Test case: 20 mrad X-angle, LumiCal sits on detector axis Unknown beam offset (amount, angle) Simulation includes detector radius resolution and bias (Pad LumiCal) Other parameters known What will be the error on luminosity after using MC to correct DATA ? Exercise Tel Aviv University HEP Experimental Group

24. Collaboration High precision design Krakow2006 Tel Aviv University HEP Experimental Group N1N1 N2N2 N3N3 N4N4 X (cm) Y (cm) 20mrad X-angle Detector axis

25. Collaboration High precision design Krakow2006 Tel Aviv University HEP Experimental Group Events (up – down) Events (right – left) 1 mm beam shift 0.5 mm beam shift 0.3 mm beam shift “Beam position”

26. Collaboration High precision design Krakow2006 Tel Aviv University HEP Experimental Group 20mrad X-angle Detector axis Before correction after correction ΔL/L~10 -2 ΔL/L~10 -3 But !!!!!! This is assuming knowing in perfect precision many parameters

27. Collaboration High precision design Krakow2006 Tel Aviv University HEP Experimental Group

28. Collaboration High precision design Summary Krakow2006 Our recommendation at ECFA2005 still holds Tel Aviv University HEP Experimental Group

29. Collaboration High precision design Beam hole BeamCal r min =1.5 cm r max =10 cm LumiCal r min =8 cm r max =28 cm Head-on design Overlap region Krakow2006 Tel Aviv University HEP Experimental Group

30. Collaboration High precision design X- angle design (step 1) Beam hole BeamCal r min =2 cm r max =16 cm LumiCal r min =13 cm r max =28 cm (Reasonable Statistics) Krakow2006 Tel Aviv University HEP Experimental Group

31. Collaboration High precision design BeamCal + 30 o blind area (incoming beam) Detectors are centered around the outgoing beam X- angle design (step-2) Krakow2006 Tel Aviv University HEP Experimental Group

32. Collaboration High precision design Krakow2006 Tel Aviv University HEP Experimental Group http://alzt.tau.ac.il/~ronen/ Username: ronen Password : msc