experimental studies on kaonic atoms at da ne
DESCRIPTION
Experimental Studies on Kaonic Atoms at DA NE. LNF - Italy SMI - Austria INFN Trieste - Italy IPNE - Romania Univ. Fribourg - Switzerland Univ. Neuch â tel - Switzerland RIKEN - Japan Univ. Tokyo - Japan Univ. Victoria - Canada UCB - USA. Johann Zmeskal - PowerPoint PPT PresentationTRANSCRIPT
FB18, Santos JZ / Aug. 25, 2006
Experimental Studies on Kaonic Atoms
at DANE
Johann Zmeskal Stefan Meyer Institute for subatomic Physics
Austrian Academy of Sciences, Vienna, Austria
for the DEAR/SIDDHARTA Collaborations
18th International IUPAP Conferenceon Few-Body Problems in Physics
Aug. 21 – 26, 2006 - Santos, Brazil
LNF - ItalySMI - AustriaINFN Trieste - Italy IPNE - RomaniaUniv. Fribourg - SwitzerlandUniv. Neuchâtel - SwitzerlandRIKEN - JapanUniv. Tokyo - JapanUniv. Victoria - CanadaUCB - USA
2FB18, Santos JZ / Aug. 25, 2006
Content
Motivation The DEAR experimental set-up Kaonic atom measurements with
DEAR Results on kaonic nitrogen Results on kaonic hydrogen
The SIDDHARTA project New X-ray detectors New setup Physics goals
Summary & Outlook
3FB18, Santos JZ / Aug. 25, 2006
Experiments with exotic atoms,
a broad research field
K-p, K-d-p, -d….
4FB18, Santos JZ / Aug. 25, 2006
Motivations
K-p simplest exotic atom with strangeness
strong interaction shift ε1s and width Γ1s
directly observable by X-ray spectroscopy
K-p: Information on Λ(1405) antikaon bound nuclear clusters
(A. Gal P24, Theory overview of antikaon bound state
N.V. Shevchenko R1-26, Search for a K-pp bound state)
kaonic hydrogen, precision data missing
kaonic deuterium never measured before
5FB18, Santos JZ / Aug. 25, 2006
Kaonic Hydrogen - Goals
Measurement of strong interaction shift and width of kaonic hydrogen and kaonic deuterium with an accuracy of a few eV
Determination of the isospin dependent scattering lengths near threshold
no extrapolation to zero energy
Testing chiral symmetry breaking in systems with strangeness
6FB18, Santos JZ / Aug. 25, 2006
Review – results before DEAR
K-p interaction attractive/repulsive ? Solution by KEK experiment
wid
th
1s
[eV
]
KpX
-500 50000
200
400
600
800
1000
shift 1s [eV]
Dav
ies
et a
l, 19
79
Izyc
ki e
t al,
1980
Bir
d et
al,
1983
repulsive attractive
KpX (KEK)M. Iwasaki et al, 1997
=
- 3
23 ±
63
± 11
eV
=
407
± 2
08 ±
100
eV
7FB18, Santos JZ / Aug. 25, 2006
Strong Interaction in K-p
1s
1s
s p d f
E1s}
E2p
n
43
2
1
K
Due to the strong interaction kaon-protonthe 1s level is shifted and broadened
Shift and width of states n>1negligible
KkeV
ε1s = E2p-1s(meas.) – E2p-1s(e.m.)
8FB18, Santos JZ / Aug. 25, 2006
Scattering Lengths
Relation of strong interaction shift and width to the complex Kp scattering length aK-p
)(
4122)0(2
21232
1
ThirringBaumannGoldbergerDeser
aeVfmaaipKpKpKs
For the determination of the isospin dependent scattering lengths a0 and a1 the hadronic shift and width of kaonic hydrogen and kaonic deuterium are necessary
9FB18, Santos JZ / Aug. 25, 2006
Requirements
Kaon Beam at DANE with unique performance
Slow, nearly monochromatic kaons (E~16 MeV) Kaon pair emitted back-to-back Low hadronic background
Target System Cryogenic gas target, pure hydrogen gas Thin windows, light-weight construction
X-ray Detector Large active area Superior energy resolution Background suppression capability
Calibration “online“ calbration – fluorescence lines
10FB18, Santos JZ / Aug. 25, 2006
DANE (LNFrascati)
electron – positron collider collision energy tuned to the Φ resonance at 1.02 GeV c.m.
electron – positron collider collision energy tuned to the Φ resonance at 1.02 GeV c.m. DEAR
11FB18, Santos JZ / Aug. 25, 2006
DEAR Setup at DAΦNE
TMP
CCD electronics
Vacuum chamber
APD Cryo-Cooler
Target Cell
CCD cooling
CCD pre-amplifier
CCD55-chips
e+ e-
K-
12FB18, Santos JZ / Aug. 25, 2006
CCD X-ray Detection
Array of 16 CCD55-30 -1242 x 1152 pixels / chip- pixel size 22.5 x 22.5 µm- total area per chip 7.24 cm2
- depletion depth ~30 µm- read-out time per CCD 2 min.- energy resolution ~150 eV @ 6keV- temperature stabilized at 165 K
Array of 16 CCD55-30 -1242 x 1152 pixels / chip- pixel size 22.5 x 22.5 µm- total area per chip 7.24 cm2
- depletion depth ~30 µm- read-out time per CCD 2 min.- energy resolution ~150 eV @ 6keV- temperature stabilized at 165 K
13FB18, Santos JZ / Aug. 25, 2006
DEAR Target
Light-weight cylindrical target structure
Diameter: 12.5 cmHeight: 14 cmVolume: 1150 ccm Side wall: 75 µm HostaphanEntrance window: 125 µm HostaphanGrid structure: glass fiber reinforced epoxy
Hydrogen filling:Temperature: 25 K (hydrogen)Pressure: 2 barDensity: 2.1 g/l (3 % LHD)
Light-weight cylindrical target structure
Diameter: 12.5 cmHeight: 14 cmVolume: 1150 ccm Side wall: 75 µm HostaphanEntrance window: 125 µm HostaphanGrid structure: glass fiber reinforced epoxy
Hydrogen filling:Temperature: 25 K (hydrogen)Pressure: 2 barDensity: 2.1 g/l (3 % LHD)
kaon
14FB18, Santos JZ / Aug. 25, 2006
Kaonic nitrogen
published in : Phys. Lett. B 593 (2004) 48-54
15FB18, Santos JZ / Aug. 25, 2006
Resulting K-p X-ray Spectrum
X-ray energy spectrum with all background fit-components subtracted
1s = - 193 ± 37 (stat.) ± 6 (syst.) eV1s = 249 ± 111 (stat.) ± 30 (syst.) eV
1s = - 193 ± 37 (stat.) ± 6 (syst.) eV1s = 249 ± 111 (stat.) ± 30 (syst.) eVAt lowest order:
aK-p= (-0.468 ± 0.090stat± 0.015syst) + i(0.302± 0.135stat± 0.036syst) fm
16FB18, Santos JZ / Aug. 25, 2006
DEAR Resultsw
idth
1
s[e
V]
KpX
-500 50000
200
400
600
800
1000
shift 1s [eV]
Dav
ies
et a
l, 19
79
Izyc
ki e
t al,
1980
Bir
d et
al,
1983
repulsive attractiveKpX (KEK)M. Iwasaki et al, 1997
=
- 3
23 ±
63
± 11
eV
=
407
± 2
08 ±
100
eV
DEAR
17FB18, Santos JZ / Aug. 25, 2006
From DEAR to SIDDHARTA
Precision of the DEAR result limited by high X-ray background (S/N~1:70)
Next step: background reduction by using kaon – X-ray time correlation(expected background suppression~ 3 orders of magnitude S/N ~ 10:1 for kaonic hydrogen)
New X-ray detectors SDDs
New dedicated target-detector set-up
18FB18, Santos JZ / Aug. 25, 2006
New X-ray Detector - SDD
New X-ray detectors with timing capability background suppression
by using the kaon - X ray time correlation excellent energy resolution high intrinsic efficiency, large area
Development of large area SDD detectors
JRA10 in I3HP (EU FP6)
19FB18, Santos JZ / Aug. 25, 2006
Silicon Drift Detector SDD
Large area SDD with 1 cm2 active area3 SDD on 1 chip
SDD has small capacitance low noise Good energy resolution, comparable with CCD But: timing capability (t < 0.5 µs)
SDD with JFET
20FB18, Santos JZ / Aug. 25, 2006
Performance of Large SDDs
First application of large (1 cm2) SDDs in K-He experiment at KEK (see talk by S. Okada at this Workshop)
21FB18, Santos JZ / Aug. 25, 2006
Triple coincidence: SDDX * ScintK * ScintK
Scintillator
Scintillator
hydrogen gas
SD
De+
e-
K+
K-
X-ray
Background suppression
22FB18, Santos JZ / Aug. 25, 2006
Energy (keV)Energy (keV)
No timingSDD‚single‘
coinc.SDD * Scint * Scint
Backgroundsuppressionto < 10-3
Kaonic deuterium
K K
Ag K fluorescencelines (calibration)
Kaonic Deuterium (MC)
23FB18, Santos JZ / Aug. 25, 2006
SIDDHARTA Setup
Cryogenic setup
SDD array(~200 cm2 SDDs)
24FB18, Santos JZ / Aug. 25, 2006
SDD unit (2x3x3 SDDs)
25FB18, Santos JZ / Aug. 25, 2006
SIDDHARTA Setup cont‘d
Cryogenic target cell
Target cell – SDD array assembly
Cryogenic target cell75 µm Kapton within a pure aluminum gridPmax. ~ 5 bar
26FB18, Santos JZ / Aug. 25, 2006
SIDDHARTA Setup – side view
C C
BB
SIDDHARTA SETUPSchnitt A-A
571,
0084
8,00
1190,00
105,
00
1524
,00
SDD ArrayGas target
Beam pipe
Kaon Detector
27FB18, Santos JZ / Aug. 25, 2006
Material Analysis by PIXE
Carefully selected structure materials analyzed by PIXE@VERA:Avoiding iron content
28FB18, Santos JZ / Aug. 25, 2006
Monte Carlo Results
Co
un
ts
Energy [keV] Energy [keV]
K-p K-dKα
Kβ
Kγ
Khigh
Monte Carlo simulated X-ray spectra (data taking 30 days).Measurement with SDD array and kaon trigger.
K-p: ε1s = 193 eV, Γ1s = 249 eV, Y(Kα )=2%ε1s= 2eV, Γ1s= 4eV
K-d: ε1s = 325 eV, Γ1s = 630 eV, Y(Kα )=0.2%ε1s= 18eV, Γ1s= 45eV
29FB18, Santos JZ / Aug. 25, 2006
SIDDHARTA - Outlookw
idth
1
s[e
V]
KpX
-500 50000
200
400
600
800
1000
shift 1s [eV]
Dav
ies
et a
l, 19
79
Izyc
ki e
t al,
1980
Bir
d et
al,
1983
KpX (KEK)M. Iwasaki et al, 1997
=
- 3
23 ±
63
± 11
eV
=
407
± 2
08 ±
100
eV
DEAR
SIDDHARTA
30FB18, Santos JZ / Aug. 25, 2006
Outlook
Future physics program at DAΦNE
Measurement of kaonic deuterium
(first measurement ever)
Precision measurement of kaonic hydrogen
(at the percent level).
Further perspectives: Kaonic helium studies with 3He and 4He targets
Precision measurement of charged kaon mass
31FB18, Santos JZ / Aug. 25, 2006
SUMMARY
First production of exotic atoms at DAΦNE, Successful measurements on kaonic hydrogen
New X-ray detector (SDD array) and setup in preparation,
Installation at DAΦNE 2007
repulsive shift in K-p verified smaller shift and width values, higher precision
32FB18, Santos JZ / Aug. 25, 2006
Spare
33FB18, Santos JZ / Aug. 25, 2006
Results on kaonic nitrogen
3 X-ray transitions - first measured
extraction of the transition yields for 7-6, 6-5, 5-4
34FB18, Santos JZ / Aug. 25, 2006
K-p and K-d Atoms
Kaonic Atom Kaonic Hydrogen
Kaonic Deuterium
e.m. positionof K line (eV)
6480 7810
1s (eV) ~200 (DEAR) *) theory
1s (eV) ~250 (DEAR) *) theory
X-ray Yield (K ) 1-3 % ~0.2% (estimate)*) new studies: c.f. A.N. Ivanov et al., Eur.Phys.J. A 23 (2005) 79,
U.-G. Meißner, U. Raha and A. Rusetsky, arXiv:nucl-th/0603029, 2006
K-p (K-d) e.m. bound kaonic atoms, Bohr radius ~80 fm