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Overview of the KOPIO Detector

Overview of the KOPIO Detector. 2005 RHIC & AGS Users ’ Meeting Brookhaven National Laboratory June 20, 2005 David E. Jaffe. Observing K L  0 . Poor kinematic signature: 3-body decay Neutral initial and final states Only outgoing  0  gg is observable

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Overview of the KOPIO Detector

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  1. Overview of the KOPIO Detector 2005 RHIC & AGS Users’ Meeting Brookhaven National Laboratory June 20, 2005 David E. Jaffe

  2. Observing KL0 • Poor kinematic signature: 3-body decay • Neutral initial and final states • Only outgoing 0gg is observable • SM prediction Br(KL0) = 3x10-11 • Main background is KL0 0 with Br=9.3x10-4 which implies a need for suppression of >7x107 “Experimentally, the problems are perhaps best represented by the statement that nobody has shown that a measurement of this decay is absolutely impossible” F.J.Gilman, “CP violation in Rare K Decays”, Blois CP Violations 1989:481-496 David E. Jaffe 2005 RHIC & AGS Users’ meeting

  3. Experimental Search for KL0 KTeV Results using ‘pencil’ beam PL B447(1999)240. E391a using same technique and is the first dedicated experiment to search for KL0 David E. Jaffe 2005 RHIC & AGS Users’ meeting

  4. KOPIO technique: work in KL CMS Measure everything possible Microbunched KL beam Measure g directions in PR Measure g energy in CAL Reconstruct 0 from gg Measure KL velocity from TOF Photon Veto (PV) Charged Particle Veto (CPV) Kinematic veto David E. Jaffe 2005 RHIC & AGS Users’ meeting

  5. David E. Jaffe 2005 RHIC & AGS Users’ meeting

  6. KOPIO technique: work in KL CMS Measure everything possible Microbunched KL beam Measure g directions in PR Measure g energy in CAL Reconstruct 0 from gg Measure KL velocity from TOF Photon Veto (PV) Charged Particle Veto (CPV) Kinematic veto David E. Jaffe 2005 RHIC & AGS Users’ meeting

  7. Microbunch Width Simulations predict s = 180ps utilizing new 25 and 100MHz cavities Data Simulation 93 MHz cavity at 22 kV gaves= 240 ps. 93 MHz cavity at 22 kV gaves = 217 ps. Data Simulation Microbunch time, in ns Microbunch time, in ns David E. Jaffe 2005 RHIC & AGS Users’ meeting

  8. Interbunch Extinction Extinction performance at high AGS intensities last remaining issue to be verified Data Simulation 4.5 MHz cavity at 130 kV gavee= 8 (+/- 6) x 10-6 4.5 MHz cavity at 130 kV gavee= 1.7 (+/- 0.9) x 10-3. Interbunch events Simulation Data Interbunch events Microbunch time, in ns Microbunch time, in ns David E. Jaffe 2005 RHIC & AGS Users’ meeting

  9. KOPIO technique: work in KL CMS Measure everything possible Microbunched KL beam Measure g directions in PR Measure g energy in CAL Reconstruct 0 from gg Measure KL velocity from TOF Photon Veto (PV) Charged Particle Veto (CPV) Kinematic veto David E. Jaffe 2005 RHIC & AGS Users’ meeting

  10. Preradiator – convert & measure  properties . . . . . .  e+ . . . 4m . e- . . . . . . Cathode strip drift chambers Extruded Scintillator & WLS fibers 64 Layers (4% X0/layer, 2.7 X0) 256 Chambers 288 Scintillator Plates (1200 m2) 150,000 Channels Readout David E. Jaffe 2005 RHIC & AGS Users’ meeting

  11. KOPIO technique: work in KL CMS Measure everything possible Microbunched KL beam Measure g directions in PR Measure g energy in CAL Reconstruct 0 from gg Measure KL velocity from TOF Photon Veto (PV) Charged Particle Veto (CPV) Kinematic veto David E. Jaffe 2005 RHIC & AGS Users’ meeting

  12. Shashlyk Photon Calorimeter Shashlyk modules prototyped and tested in beams. Required specs have all been met APD David E. Jaffe 2005 RHIC & AGS Users’ meeting

  13. KOPIO technique: work in KL CMS Measure everything possible Microbunched KL beam Measure g directions in PR Measure g energy in CAL Reconstruct 0 from gg Measure KL velocity from TOF Photon Veto (PV) Charged Particle Veto (CPV) Kinematic veto David E. Jaffe 2005 RHIC & AGS Users’ meeting

  14. Every detector is a photon veto! Fine-sampling lead/scintillator-basedshower counters of shashlyk & bar geometry. All thick enough so punch-through not an issue. KOPIO PV estimates and simulations based on BNL E949 measurements supplemented by FLUKA calculations 1 MeV Visible Energy Threshold David E. Jaffe 2005 RHIC & AGS Users’ meeting

  15. Catcher: Hadron Blind Beam  Veto beam 420 modules ofPb-Aerogel counter David E. Jaffe 2005 RHIC & AGS Users’ meeting

  16. KOPIO technique: work in KL CMS Measure everything possible Microbunched KL beam Measure g directions in PR Measure g energy in CAL Reconstruct 0 from gg Measure KL velocity from TOF Photon Veto (PV) Charged Particle Veto (CPV) Kinematic veto David E. Jaffe 2005 RHIC & AGS Users’ meeting

  17. Charged Particle Veto Performance Plastic Scintillator – backed up by  vetoes! MC 10-3 10-4 Data 10-5 10-6 • 290 David E. Jaffe 2005 RHIC & AGS Users’ meeting

  18. KOPIO technique: work in KL CMS Measure everything possible Microbunched KL beam Measure g directions in PR Measure g energy in CAL Reconstruct 0 from gg Measure KL velocity from TOF Photon Veto (PV) Charged Particle Veto (CPV) Kinematic veto David E. Jaffe 2005 RHIC & AGS Users’ meeting

  19. Kinematic Separation of Signal &Backgrounds Pion kinetic energy squared (T*2) vs Ln(Missing Energy) Signal Backgrounds David E. Jaffe 2005 RHIC & AGS Users’ meeting

  20. 3rd yr 1st yr 2nd yr Discovering/Constraining New Physics KOPIO Proposal David E. Jaffe 2005 RHIC & AGS Users’ meeting

  21. KOPIO is Unique • Only approved experiment sensitive enough reach the SM level • Uses a robust innovative technique to suppress background • Only experiment that measures the area of the unitarity triangle • Excellent discovery potential for non-SM physics David E. Jaffe 2005 RHIC & AGS Users’ meeting

  22. Extras David E. Jaffe 2005 RHIC & AGS Users’ meeting

  23. BNL scientists and KOPIO BNL physics dept scientists currently participating on KOPIO D.Beavis: Integration SSM,Vacuum,CDR J.Frank : CPV STL, CPV construction D.Jaffe : Sim. SSM, Parameters STL, CDR, 2 students/2004,1 student/2005 S.Kettell: Trig/DAQ/Offline/FEE STL, Trigger L.Littenberg: Spokesman,CDR,1student/2004,1student/2005 G.Redlinger: DAQ SSM,CDR,PV ineff’y,1student/2004 C.Scarlett:CDR,1student/2004,2students/2005 M.Sivertz:AGS SSM,CAL/PV STL, CDR, CPVconstruction, microbunch testbeam,2students/2004,1student/2005 STL=Scrub Team Leader for Apr05 NSF review CDR=author of chapter(s) in KOPIO Conceptual Design Report for Apr05 NSF review David E. Jaffe 2005 RHIC & AGS Users’ meeting

  24. The Challenge of KOPIO _ • B(KL0) ~ 310-11, need huge flux of K’s • rates inevitably rather high • Kinematic signature weak (2 particles undetectable) • Backgrounds with 0 up to 1010 times larger • Veto inefficiency on extra particles must be 10-4 • Huge flux of neutrons in beam • can make 0 off residual gas – require high vacuum • halo must be very small • hermeticity requires photon veto in this beam • Need convincing measurement of background David E. Jaffe 2005 RHIC & AGS Users’ meeting

  25. KOPIO Technique • High intensity micro-bunched beam from the AGS • Measure everything! (energy, position, angle, time) • Eliminate extra charged particles or photons • KOPIO: p0 inefficiency < 10-8 • Suppress backgrounds • Predict backgrounds from data:dual cuts • Use “blind” analysis techniques • Test predictions “outside the box” • Weight candidate events with S/N likelihood function David E. Jaffe 2005 RHIC & AGS Users’ meeting

  26. 40 ns between microbunches Need AGS to provide • Proton Beam • 100TP/spill (upgraded from present 70TP) • ~5s spill, 2.3s interspill • Microbunching • Extract debunched beam resonantly between empty buckets • 25MHz frequency • 200ps bunch width • 10-3 interbunch extinction • Kaon Beam • 42.5o take-off angle • Soft momentum spectrum • 0.5-1.5 GeV/c • 3108 KL/spill • 8% decay • 10 GHz neutrons =200 ps David E. Jaffe 2005 RHIC & AGS Users’ meeting

  27. Preradiator – convert & measure  properties . . . . . .  e+ . . . 4m . e- . . . . . . Cathode strip drift chambers Extruded Scintillator & WLS fibers 64 Layers (4% X0/layer, 2.7 X0) 256 Chambers 288 Scintillator Plates (1200 m2) 150,000 Channels Readout David E. Jaffe 2005 RHIC & AGS Users’ meeting

  28. KOPIO Prototype Measurements – BNL LEGS Tagged Photon Beams Preradiator Angular resolution: 25 mr at 250 MeV/c Simulations agree with measurements. David E. Jaffe 2005 RHIC & AGS Users’ meeting

  29. Shashlyk Photon Calorimeter Shashlyk modules prototyped and tested in beams. Required specs have all been met APD David E. Jaffe 2005 RHIC & AGS Users’ meeting

  30. Beam test of Calorimeter modules Simulation: Combined PR +CAL Energy Resolution David E. Jaffe 2005 RHIC & AGS Users’ meeting

  31. Charged Particle Veto in vacuum David E. Jaffe 2005 RHIC & AGS Users’ meeting

  32. Charged Particle Veto Performance Plastic Scintillator – backed up by  vetoes! MC 10-3 10-4 Data 10-5 10-6 • 290 David E. Jaffe 2005 RHIC & AGS Users’ meeting

  33. Every detector is a photon veto! US Wall Barrel veto Preradiator Prerad outer veto Calorimeter g vetoes in D4 sweeping magnet g vetoes in DS vacuum pipe Fine-sampling lead/scintillator-based shower counters of shashlyk & bar geometry. All thick enough so punch-through not an issue. All with sufficient efficiency David E. Jaffe 2005 RHIC & AGS Users’ meeting

  34. E949 Single g Ineff’y Measurement K2 Decay + 2 1 David E. Jaffe 2005 RHIC & AGS Users’ meeting

  35. Photon Veto Inefficiency KOPIO PV Estimates and Simulations based on improved BNL E949 Measurements supplemented by FLUKA calculations 1 MeV Visible Energy Threshold David E. Jaffe 2005 RHIC & AGS Users’ meeting

  36. Catcher: Hadron Blind Beam  Veto beam Aerogel Counter 420 modules ofPb-Aerogel counter David E. Jaffe 2005 RHIC & AGS Users’ meeting

  37. Catcher R&D results Modules prototyped and tested in beams. David E. Jaffe 2005 RHIC & AGS Users’ meeting

  38. KL modes simulated for bkgnd studies Largest back-grounds David E. Jaffe 2005 RHIC & AGS Users’ meeting

  39. Other Backgrounds • K+ contamination of beam: <0.001 of signal rate • KLK+e-, K-e+: ~ 0.001 of signal rate • nN p0N: negligible production from residual gas in decay volume if pressure<10-6 Torr. Requirements on reconstructed ZV(KL) suppress rate from US wall to <0.01 of signal rate • n: far smaller than neutron background • Hyperons: <10-5 of signal rate • Fake photons < 0.05 of signal rate assuming ~10-3 10-3 suppression from (vetoing)  (g/n discrimination) • Two KL giving single candidate: negligible due to vetoes • (KL pX)  (p p0e ): ~0.01 of signal rate • KS p0p0: ~4  10-4 of KL p0p0 background rate _ David E. Jaffe 2005 RHIC & AGS Users’ meeting

  40. Kinematic Separation of Signal &Backgrounds Pion kinetic energy squared (T*2) vs Ln(Missing Energy) Signal Backgrounds David E. Jaffe 2005 RHIC & AGS Users’ meeting

  41. David E. Jaffe 2005 RHIC & AGS Users’ meeting

  42. _ • KTeV (FNAL): B(KL0) < 5.910-7 (90% CL) • KEK E391a >10-9 ??  J-PARC LOI • KOPIO (BNL): single event sensitivity <10-12 • Discovery(5) for B(KL0)>510-11 or <1.8 10-11 • If nothing new, ~300 SM events • Rule out BRs outside of (10.17)BRSM @ 95%CL • Bound operators, B-system can’t access _ David E. Jaffe 2005 RHIC & AGS Users’ meeting

  43. KOPIO Parameters • m bunch width (extinction) 200ps (10-3) • Beam halo 10-4 • Vacuum 10-7 Torr • g resolution @ 250MeV 25 mr • Eg resolution 2.7%/ Eg(GeV) • tg resolution 90ps/  Eg(GeV) • g veto inefficiency(outside beam) E949 or better • g veto efficiency(inside beam) >99% at 300 MeV • n efficiency (inside beam) <0.3% at 800 MeV • Charged particle inefficiency 210-5(p+), 1.210-4(p-) David E. Jaffe 2005 RHIC & AGS Users’ meeting

  44. Preradiator 4m 64 Layers (4% X0/layer, 2.7 X0) 256 Chambers 288 Scintillator Plates (1200 m2) 150,000 Channels Readout David E. Jaffe 2005 RHIC & AGS Users’ meeting

  45. Primary detection mode: Secondary mode: 2 photons covert in preradiator 1 photon in preradiator, 1 in BV Reconstruct 1ste+e- in “Preradiator”, Point to K decay vertex in vacuum David E. Jaffe 2005 RHIC & AGS Users’ meeting

  46. Shashlyk Beam Measurements Simulation: Combined PR + CAL Energy Resolution David E. Jaffe 2005 RHIC & AGS Users’ meeting

  47. Barrel Veto/Calorimeter • Cylindrical array of 840 modules with 2.5m ID • Both signal detection and vetoing functions • 1g in prerad + 1g in BV/C • Modified version of calorimeter shashlyk technology, pmt readout • Energy resolution calculated to be almost as good as calorimeter • Time resolution should be comparable • B V/C lined with thin, high-efficiency, charged particle veto scintillators US end of barrel sealed by wall of plate shower-counter vetoes David E. Jaffe 2005 RHIC & AGS Users’ meeting

  48. D4 & downstream vetoes • Charged & g vetoes in D4 sweeping magnet • Field sweeps vertically • DS vetoes detect g’s emerging from the beam • Lead/scintillator plate sandwich counters • Hermeticity completed by catcher veto at the back David E. Jaffe 2005 RHIC & AGS Users’ meeting

  49. Rejections K * PV2 K * C2 * PV K * C2 K * PV4 Primary Backgrounds Worst backgrounds are from KL decay David E. Jaffe 2005 RHIC & AGS Users’ meeting

  50. Simulation Tools • GEANT3 • FLUKA, GCALOR, GHEISHA hadronic packages • GEANT4 • FLUKA • MCNPX • MARS • KOPTICs • custom optics simulator • FastMC • uses input from detailed simulators + input from experiments • Critical parameters directly measured • Either in prototype tests or experiments David E. Jaffe 2005 RHIC & AGS Users’ meeting

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