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Catalina Petrascu (Curceanu) for the DEAR Collaboration 26th LNF Scientific Committee meeting

D E A R eXperiment D A F NE E xotic A toms R esearch. DEAR: Status of analysis. Catalina Petrascu (Curceanu) for the DEAR Collaboration 26th LNF Scientific Committee meeting Frascati, 2 9 – 30 May 2003. First results of the kaonic hydrogen data analysis and

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Catalina Petrascu (Curceanu) for the DEAR Collaboration 26th LNF Scientific Committee meeting

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  1. D E A ReXperimentDAFNE Exotic Atoms Research DEAR: Status of analysis Catalina Petrascu (Curceanu) for the DEAR Collaboration 26th LNF Scientific Committee meeting Frascati, 29 – 30 May 2003

  2. First results of the kaonic hydrogen data analysis and final results on kaonic nitrogen

  3. D E A ReXperimentDAFNE Exotic Atoms Research Contents Introduction Kaonic nitrogen: final results Kaonic hydrogen: preliminary results on all the statistics The DEAR scientific program: where we stand Future plans

  4. 1. Introduction

  5. Having optimized:- DAFNE for DEAR (luminosity and background);- DEAR: shielding and setup

  6. DEAR Cryogenic setup APD Cryo Cooler Varian Turbo Molecular Pump CCD Electronics CryoTiger, CCD Cooling Cooling Lines Vacuum Chamber CCD Pre-Amplifier Boards CCD55-Chip (total of 16 chips) Hydrogen Target Cell Kaons from DANE

  7. DEAR Cryogenic Target Cell

  8. CCD-55 mounting, cryogenics and on-cell electronics - fiber-glass frames - cooling system mounted on the top - minimized Al cold finger (behind CCDs) - reduced diameter of the socket group and, consequently, of the vacuum chamber

  9. DEAR shielding Pb walls Target Vacuum jacket shielding Pb platform Quadrupole shield Lead shielding Overall shielding factor of the DEAR interaction region ~ 100

  10. November – December 2002 – kaonic hydrogen measurement performed

  11. DEAR on DAFNE autumn 2002

  12. Collected data: • -Kaonic Nitrogen: • 6 – 28 October (about 17 pb-1 – 10 pb-1 in stable conditions); • -Kaonic Hydrogen: • 30 October – 16 December: about 60 pb-1 • Background data (no collisions) for KH: • 16 – 23 December October – December 2002 DAQ

  13. The first phase of the DEAR Scientific program is completedResults of this phase are hereby presented

  14. 2. Kaonic nitrogen: final results

  15. Objectives of kaonic nitrogen measurement # Background study and reduction; optimization of the kaon stopping point distribution (i.e. degrader shaping) # First exotic atom measurement at DAFNE # KN Physics: yield measurements (exotic atom cascade); - test of a future precision measurement of the charged kaon mass

  16. Kaonic nitrogen:2002 final results

  17. Kaonic Nitrogen(October 2002) integrated luminosity 10 pb-1 (T = 85 K, P = 1.01 bar, density = 4.4 g/l) • Pattern of 3 • transitions: • 7 -> 6 at 4.6 keV • 6 -> 5 at 7.6 keV • 5 -> 4 at 14.0 keV

  18. Kaonic Nitrogen, 10 pb-1 (October 2002) Background subtracted spectrum • Pattern of 3 lines: • 2690 +/- 650 ev. at 4.6 keV • 5320 +/- 395 ev. at 7.6 keV • 1360 +/- 330 ev. at 14.0 keV

  19. Kaonic Nitrogen Physics • First determination of the yield of 3 Kaonic Nitrogen X-ray transitions: 7  6 (33.7 +/- 8.1 +/- 3.4)% 6  5 (55.5 +/- 4.2 +/- 5.5)% 5  4 ( 66.4 +/- 15.6 +/- 6.4)% • Mass of the kaon – as a test measurement: mK- = 493.884 +/- 0.314 MeV (Ph. D. thesis, paper to be submitted to Phys. Lett. B)

  20. 3. Kaonic hydrogen(November – December 2002)- preliminary results -

  21. Last Committee (November 2002) presentation:

  22. First Kaonic Hydrogen at DANE (Nov. 2002) integrated luminosity: 20 pb-1 very preliminary

  23. Kaonic Hydrogen 1800 events in 6.3 keV-region: 500 events Fe + 1300 events KH very preliminary extrapolated JZ / 26.11.02

  24. Kaonic Hydrogen,80 pb-1 Monte Carlo simulated spectrum 7000 events K 14000 events K-complex -1 ~ 33eV

  25. Request to the 25th Scientific Committee # To continue until we get an integrated luminosity of at least 80 pb-1 to permit a measurement at the level of ~ 33 eV, assuming the present machine conditions.

  26. What we have obtained: # 60 pb-1 of integrated luminosity which allowed (very preliminary result) a measurement at the level of ~ 40 eV goal was fulfilled

  27. Two independent analyses were performed:- a global fit of the KH spectrum;- a (measured) background subtracted spectral analysis

  28. I) GLOBAL FIT OF KH spectrum

  29. Kaonic Hydrogen (2002 data)- global fit integrated luminosity: 60 pb-1 120000 100000 80000 Events/ 60 eV 60000 very preliminary ? 40000 20000 Kcomplex very preliminary Ka 0 6 4 8 10 12 14 16 X-ray energy (KeV)

  30. Kaonic Hydrogen (2002 data)- global fit Background + Fe subtracted spectrum 2500 • = (160 +/- 30 +/- 15) eV G = (165 +/- 50 +/- ?) eV Tib Au - Lb 2000 Ka = 3300 +/- 1200 ev. Kcompl = 6600 +/- 2000 1500 Events/ 60 eV Au - La Cab Ka Pb 1000 Kcomplex 500 KC ? 0 very preliminary 4 5 6 7 8 9 10 11 12 X-ray energy (KeV)

  31. II) Measured background subtracted spectral analysis

  32. Kaonic Hydrogen (2002 data) Measured Kaonic Hydrogen spectrum Ka Kcomplex

  33. Kaonic Hydrogen (2002 data) Measured background spectrum

  34. Kaonic Hydrogen (2002 data) Divided spectrum • No Ti • No Ca • No Fe

  35. Kaonic Hydrogen (2002 data) Normalized measured spectra Ka Kcomplex

  36. Kaonic Hydrogen (2002 data) Measured background subtracted spectrum very preliminary ? Ka = 3000 +/- 1400 ev. Kcomplex= 7000 +/- 2400 • = (165 +/- 40) eV G = (240 +/- 86) eV

  37. Kaonic Hydrogen (2002 data) Measured background subtracted spectrum - smoothed very preliminary ?

  38. Results of the KH analyses:(Very preliminary) Ka = 3100 +/- 1300 ev. Kcomplex= 6800 +/- 2400 Two independent preliminary analyses of the 60 pb-1 collected data were performed – results in very good agreement: e= (162 +/- 40) eV G = ~( 200+/- 80) eV

  39. 4. The DEAR scientific program: where we stand

  40. DEAR and the rest of the world • = (162 +/- 40) eV G = (200+/- 80) eV The obtained results: represent the best measurement performed on Kaonic Hydrogen up to now

  41. Kaonic hydrogen: summary of data 1000 Constant Scattering Length K-Matrix Potential Model Cloudy Bag Model Consituent Quark Model 800 600 Izycki et al, 1980 400 200 Bird et al, 1983 0 Davies et al, 1979 -500 0 500 Shift (eV) [ e ] Width (eV) [G] DEAR preliminary result Iwasaki et al, 1997 KpX

  42. MORE on KH analysis: 1) Refine quality of data – Charge Transfer corrections 2) Finalize the analysis with the good quality data 3) Careful study of the systematic errors 4) Interpretation of the results: challenge for theorist SPRING SCHOOL 19-23 May - contact with Bern and Bonn groups (Gasser, Rusetsky: Ph. D. Student on KH interpretation – revival of interest)

  43. 5. Future plans

  44. Next Steps of the DEAR Scientific Program # few eV precision measurement of kaonic hydrogen 1s level shift; # few eV precision measurement of kaonic deuterium1s level shift in order to determine the isospin dependent antikaon nucleon scattering lengths at percent level precision

  45. Monte Carlo simulations with the SDD triggerable setup(see talk of C. Fiorini) # Percent precision measurement of kaonic hydrogen transition – with 50 pb-1;

  46. Kaonic Hydrogen Monte Carlo simulation in realistic conditions Precision on shift ~ 3 eV 50 pb-1 S/B = 1/1

  47. Further plans # Kaonic helium measurement (“kaonic helium puzzle”);# Other light kaonic atoms measurement (Li, Be…);# Charged kaon mass precision measurement# Investigate the possibility of the measurement of other types of hadronic exotic atoms (sigmonium?)

  48. How to reach these goals? NEXT TALK…..(C. Fiorini – Politecnico di Milano)

  49. Acknowledgements The DAFNE machine staff is warmly thanked by the DEAR group. The success of the difficult kaonic hydrogen measurement has its origin in a happy collaboration machine – experiment, which has been continuously enriched by new ideas and clever solutions to all problems.

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