1. ENERGY RECOVERY OF THE CMS ELECTROMAGNETIC CALORIMETER DEAD CHANNELS Daskalakis Georgios, Geralis Theodoros, Kesisoglou Stilianos, Manolakos Ioannis, Eleni Ntomari 1 XXIX Workshop on Recent Advances in Particle Physics and Cosmology

2.  Introduction  Description of the method  Position Estimation  Energy Estimation  Conclusions-future plans Outline 5/11/2015 Eleni Ntomari - NCSR Demokritos2

3. 5/11/2015 Eleni Ntomari - NCSR Demokritos3 CMS detector ECAL  One of the most accurate, distinctive and important subdetectors of the CMS experiment Measurements of electrons and photons with an excellent energy resolution  essential in the search for new physics, in particular for the postulated Higgs boson.

4. ECAL Endcap ECAL Barrel  61 200 lead tungstate (PbWO4 ) crystals mounted in the central barrel  7 324 crystals in each of the two endcaps 5/11/2015 Eleni Ntomari - NCSR Demokritos4

5. ECAL Endcap ECAL Barrel 5/11/2015 Eleni Ntomari - NCSR Demokritos5  The electromagnetic calorimeter is designed to perform precision measurements aiming to reach 0.5% energy resolution at high energy. 36 supermodules made of 85x20 crystals, each one divided into 4 modules. Each Endcap is divided into 2 halves and is logically organized in 9 sectors of 40 degrees each.  A preshower detector is placed in front of the endcap crystals. identify neutral pions in the endcaps within a fiducial region 1.653 < |η| < 2.6. identification of electrons against minimum ionizing particles improves the position determination of electrons and photons with high granularity. Preshower based on Si sensors

6. Dead Channels-How important is it to develop a recovery algorithm? ~1% of the Electromagnetic Calorimeter Channels present problems (e.g. noisy channels, poor response) ->cannot be used for the energy estimation of the particles that "hit" near them. 5/11/2015 Eleni Ntomari - NCSR Demokritos6

7. Dead Channels-How important is it to develop a recovery algorithm? ~1% of the Electromagnetic Calorimeter Channels present problems (e.g. noisy channels, poor response) ->cannot be used for the energy estimation of the particles that "hit" near them. 5/11/2015 Eleni Ntomari - NCSR Demokritos7 Crystal 6 81318 7 12 17 61116

8. Dead Channels-How important is it to develop a recovery algorithm? ~1% of the Electromagnetic Calorimeter Channels present problems (e.g. noisy channels, poor response) ->cannot be used for the energy estimation of the particles that "hit" near them. 5/11/2015 Eleni Ntomari - NCSR Demokritos8 Crystal 7 81318 7 12 17 61116

9. Method description  Effort to develop recovery algorithms, in order to be able to estimate the energy of these Dead Channels, using the energy of their neighboring functioning crystals 5/11/2015 Eleni Ntomari - NCSR Demokritos9 Build position reconstruction functions using energies from all crystals in a 5x5 or 3x3 grid, except from the missing one

10. Method description 5/11/2015 Eleni Ntomari - NCSR Demokritos10  Effort to develop recovery algorithms, in order to be able to estimate the energy of these Dead Channels, using the energy of their neighboring functioning crystals Build position reconstruction functions using energies from all crystals in a 5x5 or 3x3 grid, except from the missing one Build energy correction functions using Monte Carlo Energy fraction  Dead Channel Energy

11. Method description 5/11/2015 Eleni Ntomari - NCSR Demokritos11  Effort to develop recovery algorithms, in order to be able to estimate the energy of these Dead Channels, using the energy of their neighboring functioning crystals Build position reconstruction functions using energies from all crystals in a 5x5 or 3x3 grid, except from the missing one Build energy correction functions using Monte Carlo Energy fraction  Dead Channel Energy Apply functions in areas with dead channels Tests with 2010 Collision Data

12. Method description Build position reconstruction functions using energies from all crystals in a 5x5 or 3x3 grid, except from the missing one Build energy correction functions using Monte Carlo Energy fraction  Dead Channel Energy Apply functions in areas with dead channels Tests with 2010 Collision Data Data Samples /EG/Run2010A-Sep17ReReco-v2/RECO /Electron/Run2010B-PromptReco-v2/RECO /EG/Run2010A-Nov4ReReco-v2/RECO /Electron/Run2010B-Nov4ReReco_v2/RECO 5/11/2015 Eleni Ntomari - NCSR Demokritos12  Effort to develop recovery algorithms, in order to be able to estimate the energy of these Dead Channels, using the energy of their neighboring functioning crystals

13. 81318 7 12 17 61116  Estimate the true position of the hit (photon or electron)  Photon: information of the supercluster  Electron/Positron: information of the supercluster or the tracker  Reconstruction of the event position:  Scurve Method :  Logarithmic weighted method: Event position reconstruction η φ 5/11/2015 Eleni Ntomari - NCSR Demokritos13

14. 8 18 7 12 17 61116  Estimate the true position of the hit (photon or electron)  Photon: information of the supercluster  Electron/Positron: information of the supercluster or the tracker  Reconstruction of the event position:  Scurve Method :  Logarithmic weighted method: Event position reconstruction Most energetic crystal η φ 5/11/2015 Eleni Ntomari - NCSR Demokritos14

15. 81318 7 12 17 61116  Estimate the true position of the hit (photon or electron)  Photon: information of the supercluster  Electron/Positron: information of the supercluster or the tracker  Reconstruction of the event position:  Scurve Method :  Logarithmic weighted method: Most energetic crystal Dead crystal η φ 5/11/2015 Eleni Ntomari - NCSR Demokritos15 Event position reconstruction

16. 81318 7 12 17 61116  Estimate the true position of the hit (photon or electron)  Photon: information of the supercluster  Electron/Positron: information of the supercluster or the tracker  Reconstruction of the event position:  Scurve Method :  Logarithmic weighted method: Most energetic crystal Dead crystal η φ EstimX [mm] TrueX-EstimX [mm] EstimY [mm] TrueY-EstimY[mm] 5/11/2015 Eleni Ntomari - NCSR Demokritos16 Event position reconstruction

17. Position Resolution - Crystal 6 81318 7 12 17 61116 11/04/11 Eleni Ntomari - NCSR Demokritos17 2010 Collision DATA

18. Position Resolution - Crystal 6 81318 7 12 17 61116 11/04/11 Eleni Ntomari - NCSR Demokritos18 2010 Collision DATA

19. Position Resolutions - X 5/11/2015 Eleni Ntomari - NCSR Demokritos19 2010 Collision DATA

20. Energy Correction functions (Monte Carlo e+/e-) 5/11/2015 Eleni Ntomari - NCSR Demokritos20  The most energetic crystal (12) is split in 25 subdivisions  In most of the cases, the energy fraction follows a Gaussian distribution  The Gauss fit mean value is used to extract the constants of the formula that calculates the corrected fraction: o f(η,φ): energy fraction (fr=Edc/Sum9) o n, φ: hit coordinates on the crystal o a ij : constants to be defined Fraction = f(η,φ) = Edc/sum9 → Edc = (fraction x sum8 )/(1 – fraction)

21. Energy Correction functions (Monte Carlo e+/e-) 49141924 38131823 27121722 16111621 05101520 5/11/2015 Eleni Ntomari - NCSR Demokritos21  The most energetic crystal (12) is split in 25 subdivisions  In most of the cases, the energy fraction follows a Gaussian distribution  The Gauss fit mean value is used to extract the constants of the formula that calculates the corrected fraction: o f(η,φ): energy fraction (fr=Edc/Sum9) o n, φ: hit coordinates on the crystal o a ij : constants to be defined Fraction = f(η,φ) = Edc/sum9 → Edc = (fraction x sum8 )/(1 – fraction)

22. Energy Correction functions (Monte Carlo e+/e-) 49141924 38131823 27121722 16111621 05101520 5/11/2015 Eleni Ntomari - NCSR Demokritos22  The most energetic crystal (12) is split in 25 subdivisions  In most of the cases, the energy fraction follows a Gaussian distribution  The Gauss fit mean value is used to extract the constants of the formula that calculates the corrected fraction: o f(η,φ): energy fraction (fr=Edc/Sum9) o n, φ: hit coordinates on the crystal o a ij : constants to be defined Fraction = f(η,φ) = Edc/sum9 → Edc = (fraction x sum8 )/(1 – fraction)

23. Energy Resolutions Sum8/Sum9 Sum8+Edc/Sum9 81318 7 12 17 61116 5/11/2015 Eleni Ntomari - NCSR Demokritos23 2010 Collision DATA

24. Energy Resolutions Sum8/Sum9 Sum8+Edc/Sum9 81318 7 12 17 61116 81318 7 12 17 61116 5/11/2015 Eleni Ntomari - NCSR Demokritos24 2010 Collision DATA

25. RD: Electrons (Scurve_RD_e+e-, Spline_MC_e+e-, η>0) 11/04/11 Eleni Ntomari - NCSR Demokritos25 2010 Collision DATA

26. RD: Positrons (Scurve_RD_e+e-, Spline_MC_e+e-, ceta 30, fbrem<0.1) RD: Positrons (Scurve_RD_e+e-, Spline_MC_e+e-, η>0) 11/04/11 Eleni Ntomari - NCSR Demokritos26 2010 Collision DATA

27. First analysis with Monte Carlo photons, electrons and positrons gives promising results Conclusions 11/04/11 Eleni Ntomari - NCSR Demokritos27

28. First analysis with Monte Carlo photons, electrons and positrons gives promising results Tests of this method on Real Data appears to be quite satisfactory for both electrons and positrons, as well as EB+ and EB- Conclusions 11/04/11 Eleni Ntomari - NCSR Demokritos28

29. First analysis with Monte Carlo photons, electrons and positrons gives promising results Tests of this method on Real Data appears to be quite satisfactory for both electrons and positrons, as well as EB+ and EB- The correction functions estimate correctly the impact position and the missing energy of the problematic channel Conclusions 11/04/11 Eleni Ntomari - NCSR Demokritos29

30. First analysis with Monte Carlo photons, electrons and positrons gives promising results Tests of this method on Real Data appears to be quite satisfactory for both electrons and positrons, as well as EB+ and EB- The correction functions estimate correctly the impact position and the missing energy of the problematic channel Studies will be extended in the ECAL endcaps Conclusions 11/04/11 Eleni Ntomari - NCSR Demokritos30

31. First analysis with Monte Carlo photons, electrons and positrons gives promising results Tests of this method on Real Data appears to be quite satisfactory for both electrons and positrons, as well as EB+ and EB-. The correction functions estimate correctly the impact position and the missing energy of the problematic channel. Studies will be extended in the ECAL endcaps With more data, it'll be possible to built the position corrections from data, without any usage of Monte Carlo Conclusions 11/04/11 Eleni Ntomari - NCSR Demokritos31

32. First analysis with Monte Carlo photons, electrons and positrons gives promising results Tests of this method on Real Data appears to be quite satisfactory for both electrons and positrons, as well as EB+ and EB-. The correction functions estimate correctly the impact position and the missing energy of the problematic channel. Studies will be extended in the ECAL endcaps With more data, it'll be possible to built the position corrections from data, without any usage of Monte Carlo The ultimate goal is to pass these corrections to CMS framework Conclusions 11/04/11 Eleni Ntomari - NCSR Demokritos32

33. Back up Slides 5/11/2015 33 Eleni Ntomari - NCSR Demokritos

34. 5/11/2015Eleni Ntomari - NCSR Demokritos 34

35. Energy Resolutions 5/11/2015Eleni Ntomari - NCSR Demokritos 35  Real Data (W) Electrons Positrons Scurves from electrons-positrons Real Data Spline from MC electrons-positrons

36. 5/11/2015Eleni Ntomari - NCSR Demokritos 36 RD: Electrons (Scurve_RD_e+e-, Spline_MC_e+e-)

37. 5/11/2015Eleni Ntomari - NCSR Demokritos 37 RD: Electrons (Scurve_RD_e+e-, Spline_MC_e+e-, ceta>0)

38. 5/11/2015Eleni Ntomari - NCSR Demokritos 38 RD: Electrons (Scurve_RD_e+e-, Spline_MC_e+e-, ceta<0)

39. RD: Positrons (Scurve_RD_e+e-, Spline_MC_e+e-) 5/11/2015Eleni Ntomari - NCSR Demokritos 39

40. RD: Positrons (Scurve_RD_e+e-, Spline_MC_e+e-, ceta 30, fbrem<0.1) 5/11/2015Eleni Ntomari - NCSR Demokritos 40 RD: Positrons (Scurve_RD_e+e-, Spline_MC_e+e-, ceta>0)

41. RD: Positrons (Scurve_RD_e+e-, Spline_MC_e+e-, ceta 30, fbrem<0.1) 5/11/2015Eleni Ntomari - NCSR Demokritos 41 RD: Positrons (Scurve_RD_e+e-, Spline_MC_e+e-, ceta<0)

42. Position Resolutions 5/11/2015Eleni Ntomari - NCSR Demokritos42  Real Data (W) Electrons Positrons Scurves from electrons-positrons Real Data Spline from MC electrons-positrons

43. Real Data- Electrons X-Resolution, Scurve_RD_e+e-, Spline_MC_e+e-, ceta<0 5/11/2015Eleni Ntomari - NCSR Demokritos43

44. Real Data- Positrons X-Resolution, Scurve_RD_e+e-, Spline_MC_e+e-, ceta<0 5/11/2015Eleni Ntomari - NCSR Demokritos44

45. Real Data- Electrons X-Resolution, Scurve_RD_e+e-, Spline_MC_e+e-, ceta>0 5/11/2015Eleni Ntomari - NCSR Demokritos45

46. Real Data- Positrons X-Resolution, Scurve_RD_e+e-, Spline_MC_e+e-, ceta>0 5/11/2015Eleni Ntomari - NCSR Demokritos46

47. Real Data- Electrons Y-Resolution, Scurve_RD_e+e-, Spline_MC_e+e-, ceta<0 5/11/2015Eleni Ntomari - NCSR Demokritos47

48. Real Data- Positrons Y-Resolution, Scurve_RD_e+e-, Spline_MC_e+e-, ceta<0 5/11/2015Eleni Ntomari - NCSR Demokritos48

49. Real Data- Electrons Y-Resolution, Scurve_RD_e+e-, Spline_MC_e+e-, ceta>0 5/11/2015Eleni Ntomari - NCSR Demokritos49

50. Real Data- Positrons Y-Resolution, Scurve_RD_e+e-, Spline_MC_e+e-, ceta>0 5/11/2015Eleni Ntomari - NCSR Demokritos50