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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 - PowerPoint PPT Presentation
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Catalina Petrascu (Curceanu)Catalina Petrascu (Curceanu)for the DEAR Collaboration
26th LNF Scientific Committee meeting
Frascati, 29 – 30 May 2003
D E A RD E A R
eXperiment
DANE Exotic
Atoms Research
D E A RD E A R
eXperiment
DANE Exotic
Atoms Research
ContentsContents
1. Introduction
2. Kaonic nitrogen: final results
3. Kaonic hydrogen: preliminary results on all the statistics
4. The DEAR scientific program: where we stand
5. Future plans
D E A RD E A R
eXperiment
DANE Exotic
Atoms Research
D E A RD E A R
eXperiment
DANE Exotic
Atoms Research
1. Introduction1. Introduction
Having optimized:
- DANE for DEAR (luminosity and background);
- DEAR: shielding and setup
APD Cryo Cooler
Varian Turbo Molecular Pump
CryoTiger, CCD Cooling
CCD Electronics
Vacuum Chamber
Hydrogen Target Cell
CCD Pre-Amplifier Boards
Cooling Lines
CCD55-Chip (total of 16 chips)
DEAR DEAR Cryogenic setupCryogenic setup
Kaons from DANE
DEAR Cryogenic Target CellDEAR Cryogenic Target Cell
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
DEAR shielding
Pb walls
Quadrupole shield
Pb platform
Vacuum jacket shielding
Overall shielding factor Overall shielding factor of the DEAR interaction region ~ 100of the DEAR interaction region ~ 100
Lead shielding
Target
November – December 2002 – kaonic
hydrogen measurement performed
DEAR on DADEAR on DANE autumn 2002NE autumn 2002
October – December 2002 DAQ
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
The first phase of the DEAR Scientific program is completed
Results of this phase are hereby presented
2. Kaonic nitrogen: final results2. Kaonic nitrogen: final results
Objectives of kaonic nitrogen Objectives of kaonic nitrogen measurementmeasurement
# Background study and reduction; optimization of the kaon stopping point distribution (i.e. degrader shaping)
# First exotic atom measurement at DANE
# KN Physics: - yield measurements (exotic atom cascade);
- test of a future precision measurement of the charged kaon mass
Kaonic nitrogen:Kaonic nitrogen:2002 final results2002 final results
Kaonic NitrogenKaonic Nitrogen (October 2002)(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
Kaonic Nitrogen, 10 pbKaonic Nitrogen, 10 pb-1 -1 (October 2002)(October 2002)Background subtracted spectrumBackground 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
• 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)
Kaonic Nitrogen PhysicsKaonic Nitrogen Physics
3. Kaonic hydrogen3. Kaonic hydrogen(November – December 2002)(November – December 2002)
- preliminary results -- preliminary results -
Last Committee (November Last Committee (November 2002) presentation:2002) presentation:
First Kaonic Hydrogen at DAFirst Kaonic Hydrogen at DANE (Nov. 2002)NE (Nov. 2002)
integrated luminosity: 20 pb20 pb-1-1
Kaonic Hydrogen Kaonic Hydrogen 1800 events in 6.3 keV-region: 1800 events in 6.3 keV-region: 500 events Fe 500 events Fe + 1300 events KH 1300 events KH
JZ / 26.11.02
extrapolated
7000 events K
14000 events K-complex
Kaonic Hydrogen,Kaonic Hydrogen, 80 pb80 pb-1 -1
Monte Carlo simulated spectrum
~
-1
33eV
Request to the 25th Scientific CommitteeRequest 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.
What we have obtained:What we have obtained:
# 60 pb-1 of integrated luminosity which allowed
(very preliminary result) a measurement at the level
of ~ 40 eV
Two independent analyses were Two independent analyses were performed:performed:
- a global fit of the KH spectrum;- a global fit of the KH spectrum;
- a (measured) background - a (measured) background subtracted spectral analysissubtracted spectral analysis
I) GLOBAL FIT OF KH spectrumI) GLOBAL FIT OF KH spectrum
?
Kaonic Hydrogen Kaonic Hydrogen (2002 data)- global fit(2002 data)- global fit
integrated luminosity: 60 pb60 pb-1-1
4 6 8 10 12 14 16
0
20000
40000
60000
80000
100000
120000
KKcomplex
X-ray energy (KeV)
Eve
nts
/ 60
eV
Kaonic Hydrogen Kaonic Hydrogen (2002 data)- global fit(2002 data)- global fit
Background + Fe subtracted spectrum
5 6 7 8 9 10 11
0
500
1000
1500
2000
2500
KKcomplex
X-ray energy (KeV)
Eve
nts
/ 60
eV
124
Ca
TiAu - L
PbAu - L
= (160 +/- 30 +/- 15) eV = (165 +/- 50 +/- ?) eV
KC
K = 3300 +/- 1200 ev.
Kcompl = 6600 +/- 2000
?
II) Measured background II) Measured background subtracted spectral analysissubtracted spectral analysis
Kaonic Hydrogen Kaonic Hydrogen (2002 data)(2002 data)
Measured Kaonic Hydrogen spectrum
K
Kcomplex
Kaonic Hydrogen Kaonic Hydrogen (2002 data)(2002 data)
Measured background spectrum
Kaonic Hydrogen Kaonic Hydrogen (2002 data)(2002 data)
Divided spectrum
No Ti
No Ca
No Fe
Kaonic Hydrogen Kaonic Hydrogen (2002 data)(2002 data)
Normalized measured spectra
K
Kcomplex
Kaonic Hydrogen Kaonic Hydrogen (2002 data)(2002 data)
Measured background subtracted spectrum
?
= (165 +/- 40) eV = (240 +/- 86) eV
K = 3000 +/- 1400 ev.
Kcomplex= 7000 +/- 2400
Kaonic Hydrogen Kaonic Hydrogen (2002 data)(2002 data)
Measured background subtracted spectrum - smoothed
?
Results of the KH analyses:Results of the KH analyses:(Very preliminary)
Two independent preliminary analyses of the 60 pb-1 collected data were performed – results in very good agreement:
= (162 +/- 40) eV
= ~( 200+/- 80) eV
K = 3100 +/- 1300 ev.
Kcomplex= 6800 +/- 2400
4. The DEAR scientific 4. The DEAR scientific program: where we standprogram: where we stand
DEAR and the rest of the worldDEAR and the rest of the world
The obtained results:
represent the best measurement performed on Kaonic Hydrogen up to now
= (162 +/- 40) eV
= (200+/- 80) eV
Iwas
aki e
t al,
1997
KpX
-500 50000
200
400
600
800
1000
Shift (eV) [
Dav
ies
et a
l, 19
79
Izyc
ki e
t al,
1980
Bir
d et
al,
1983
Constant Scattering LengthK-MatrixPotential ModelCloudy Bag ModelConsituent Quark Model
DEARpreliminary
result
Kaonic hydrogen: summary of data
Wid
th (
eV) [
]
MORE on KH analysis: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)
5. Future plans5. Future plans
Next Steps of the DEAR Scientific Program
# few eV precision measurement of kaonic kaonic hydrogenhydrogen 1s level shift;
# few eV precision measurement of kaonic kaonic deuteriumdeuterium 1s level shift
in order to determine the isospin dependent in order to determine the isospin dependent antikaonantikaon
nucleon scattering lengths at percent level nucleon scattering lengths at percent level precisionprecision
Monte Carlo simulations with the SDD triggerable setup(see talk of C. Fiorini)
# Percent precision measurement of kaonic kaonic hydrogenhydrogen transition – with 50 pb-1;
Kaonic Hydrogen Kaonic Hydrogen Monte Carlo simulation in realistic conditionsMonte Carlo simulation in realistic conditions
Precision on shift ~ 3 eV
50 pb-1
S/B = 1/1
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?)
How to reach these goals?
NEXT TALK…..(C. Fiorini – Politecnico di Milano)
AcknowledgementsAcknowledgements
The DANE 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.