J. Marton / IMEP RECFA Meeting, Innsbruck, March 26, 2004

EXOTIC ATOM RESEARCHAT DAΦNE

J. Marton

Institute for Medium Energy Physics

Austrian Academy of Sciences

DAFNEEXOTICATOMRESEARCH

J. Marton / IMEP RECFA Meeting, Innsbruck, March 26, 2004

Exotic Atom Research by IMEP

Main field: Hadron physics – hadronic atoms

Kaonic atoms K-p, K-d @ LNF / INFN

Contributions of IMEP to other topics in exotic atom researchSearch for nuclear clusters bound by K- (GSI, J-PARC)Antiprotonic atoms (CERN, FLAIR/GSI-future)Pionic atoms πH (PSI)Theoretical studies (collaboration with TU Vienna)

J. Marton / IMEP RECFA Meeting, Innsbruck, March 26, 2004

IMEP: Member of DEAR / SIDDHARTA

G. Beer1, A.M. Bragadireanu2, M. Cargnelli3, C. Curceanu(Petrascu)4,2, J.P. Egger5, H. Fuhrmann3, C. Guaraldo4 (spokesperson), M. Iliescu4,2, T. Ishiwatari3, K. Itahashi6, M. Iwasaki6, P. Kienle3, B. Lauss7, V. Lucherini4, L. Ludhova8, J. Marton3, F. Mulhauser8, T. Ponta2,4, L.A. Schaller8, R. Seki9,10, D. Sirghi4, F. Sirghi4, P. Strasser6 and J. Zmeskal3

1Univ. of Victoria; 2Inst. of Physics and Nuclear Engineering “Horia Hulubei”; 3Institute for Medium Energy Physics; 4INFN Laboratori Nazionali di Frascati;5Université de Neuchâtel; 6RIKEN; 7University of California; 8Université de Fribourg; 9California Institute of Technology; 10California State University

I3 Hadron Physics in FP6/EC – Joint Research Activity SIDDHARTAin cooperation with LNF, MPG, PNSensor, Politecnico Milan, IFIN-HH. SIDDHARTA

Silicon Drift Detectors for Hadronic AtomResearch by Timing Applications

SIDDHARTASilicon Drift Detectors for Hadronic AtomResearch by Timing Applications

J. Marton / IMEP RECFA Meeting, Innsbruck, March 26, 2004

Motivation

X-ray transitions in kaonic atoms – precision spectroscopy

Kaonic hydrogen isotopes: low energy QCD studiesSimplest exotic atoms with strangeness

Information on (1405) sub-threshold resonanceimportant for research on deeply bound kaonic states

Determination of the isospin dependent KN scattering lengths

Testing chiral symmetry breaking in systems with strangeness

hadronic shift ε1s and width Γ1s

directly observable by X-ray spectroscopy

kaonic hydrogen „puzzle“ solved – but: precision data missingkaonic deuterium never measured before

J. Marton / IMEP RECFA Meeting, Innsbruck, March 26, 2004

Our goals

• Measurement of the hadronic shift and width

of hydrogen at the percent level

• First measurement of kaonic deuterium

• Extraction of the isospin-dependent scattering lengths with kaonic hydrogen and kaonic deuterium data

SIDDHARTASilicon Drift Detectors for Hadronic AtomResearch by Timing Applications

SIDDHARTASilicon Drift Detectors for Hadronic AtomResearch by Timing Applications

J. Marton / IMEP RECFA Meeting, Innsbruck, March 26, 2004

DAΦNE @ LNF

Electron – Positron collider with collision energy tuned to the Φ meson resonance at 1.02 GeV c.m.

Monoenergetic kaons from Φ meson decayΦ K+ K- (branching ~ 50%)

Ideal kaon triggerPion background very smallKaon production ~ 3×106 K- per day

Ideal facility for exotic (kaonic) atom research

DEAR

J. Marton / IMEP RECFA Meeting, Innsbruck, March 26, 2004

DEAR Experimental Set-up

X-ray spectroscopy by CCD array (16 CCD-55)

J. Marton / IMEP RECFA Meeting, Innsbruck, March 26, 2004

Experiment @ DAPHNE / LNF

J. Marton / IMEP RECFA Meeting, Innsbruck, March 26, 2004

Results on Kaonic Nitrogen

Thesis T. Ishiwatari (IMEP), to be published in Phys. Lett. B

3 X-ray transitions first measured

Extraction of the transition yields

Impact on cascade calculations

Kaonic nitrogen nearly fully stripped of electrons: high precision measurement of the charged kaon mass

J. Marton / IMEP RECFA Meeting, Innsbruck, March 26, 2004

Results on Kaonic Hydrogen 2 independent data analyses by LNF and IMEP consistent results

repulsive shift verifiedsmaller shift, widthsmaller error barsK, K disentangled

Analysis by M. Cargnelli (IMEP)

Combined result for hadronic shift and width (preliminary) Shift: 1s = - 194 ± 46 eV Width: 1s = 249 ± 132 eV

J. Marton / IMEP RECFA Meeting, Innsbruck, March 26, 2004

DEAR Results (preliminary)

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 attractiveKpX (KEK)M. Iwasaki et al, 1997

=

- 3

23 ±

63

± 11

eV

=

407

± 2

08 ±

100

eV

New theoretical studies:Ivanov et al. 2003 / 2004Meißner, Raha, Rusetsky 2004

DEAR prelim.

J. Marton / IMEP RECFA Meeting, Innsbruck, March 26, 2004

• New X-ray detectors providing

– timing capability background suppression by using the kaon-X ray time correlation

– excellent energy resolution– high efficiency, large solid angle– dedicated compact geometry

Best choice:• SDD (silicon drift detectors)

R&D within SIDDHARTA

Next Steps

SIDDHARTASilicon Drift Detectors for Hadronic AtomResearch by Timing Applications

SIDDHARTASilicon Drift Detectors for Hadronic AtomResearch by Timing Applications

In the next stage of the experiment we expect a substantial improvement in signal-to-noise ratio by more than 2 orders of magnitude

J. Marton / IMEP RECFA Meeting, Innsbruck, March 26, 2004

Next Steps cont‘d

New design for target-detector system with high efficiency

Example: Toroidal Setup with SDDs (work in progress) Large area SDDs (1cm2 each, total area ~ 200 cm2)

e+

e-

Cryogenic gas target volume

SDDs

Structure material carefully selected (PIXE@VERA - Vienna)

J. Marton / IMEP RECFA Meeting, Innsbruck, March 26, 2004

Summary

DEAR one of the first experiments at DAPHNE

First production of exotic atoms at DAFNE

Measurements on kaonic nitrogen and finally kaonic hydrogen

Preliminary results on hadronic shift and width in kaonic hydrogen: repulsive hadronic shift in K-p verified. smaller values and better precision for shift and width. Kβ, Kγ resolved for the first time.

Potential of the method using SDDs demonstrated by test measurements future high precision measurements on kaonic atoms are feasible

SIDDHARTASilicon Drift Detectors for Hadronic AtomResearch by Timing Applications

SIDDHARTASilicon Drift Detectors for Hadronic AtomResearch by Timing Applications

J. Marton / IMEP RECFA Meeting, Innsbruck, March 26, 2004

Outlook

• SDDs with trigger capability (SIDDHARTA project)

• New target-detector set-up in progress

Next experiments planned

• Precison measurement of kaonic hydrogen.

• Measurement of kaonic deuterium (first ever)

• Long range perspectives: kaonic heliumPrecision measurement of kaon mass

J. Marton / IMEP RECFA Meeting, Innsbruck, March 26, 2004

Post Scriptum

"The most important experiment to be carried out in low energy K-meson physics today is the definitive determination of the energy level shifts in K-p and K-d atoms, because of their direct connection with the physics of the KN interaction and their complete independence of all other kind of measurements which bear on this interaction“

R.H. Dalitz

J. Marton / IMEP RECFA Meeting, Innsbruck, March 26, 2004

The End