Pr zisionsmessungen mit kaonischen atomen von dear zu siddharta
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Präzisionsmessungen mit kaonischen Atomen – von DEAR zu SIDDHARTA. J. Marton Stefan Meyer Institut der ÖAW on behalf of the DEAR / SIDDHARTA Collaborations. Motivation. Exotic (kaonic, pionic) hydrogen atoms are used as sensitive probes for strong interaction

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Präzisionsmessungen mit kaonischen Atomen – von DEAR zu SIDDHARTA

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Pr zisionsmessungen mit kaonischen atomen von dear zu siddharta

Präzisionsmessungen mit kaonischen Atomen – von DEAR zu SIDDHARTA

J. Marton

Stefan Meyer Institut der ÖAW

on behalf of the DEAR / SIDDHARTA Collaborations

55. Jahrestagung der ÖPG, September 2005


Motivation

Motivation

  • Exotic (kaonic, pionic) hydrogen atoms are used

  • as sensitive probes for strong interaction

    • Strong interaction shift ε1s and width Γ1s are

    • directly observable by precision X-ray spectroscopy

… Exotic atom spectroscopy provides

important input for the further development of low energy QCD. …

NuPECC Long Range Plan 2004

Fundamental Interactions:

Recommendations

55. Jahrestagung der ÖPG, September 2005


Dear collaboration @ lnf

DEAR Collaboration @ LNF

  • 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, E. Widmann3 and J. Zmeskal3

  • 1Univ. of Victoria; 2Inst. of Physics and Nuclear Engineering “Horia Hulubei”; 3Stefan Meyer Institut of the Austrian Academy of Sciences; 4INFN Laboratori Nazionali di Frascati;5Université de Neuchâtel; 6RIKEN; 7University of California; 8Université de Fribourg; 9California Institute of Technology; 10California State University

Work supported by TARI-INFN,

Contract HPRI-CT-1999-00088

and

Contract No. RII3-CT-2004-506078

55. Jahrestagung der ÖPG, September 2005


Kaonic hydrogen motivation

Kaonic Hydrogen: Motivation

Kaonic hydrogen atoms used

as probes for strong interaction

  • strong interaction shift ε1sand width Γ1s

    directly observable by X-ray spectroscopy

  • K-p: Information on Λ(1405)

     deeply bound states (kaonic nuclear Clusters)

Breaking news from KEK, [email protected]

(c.f. T. Suzuki et al., Phys. Lett. B597 (2004) 263,M. Agnello et al. PRL 94 (2005) 21303)

55. Jahrestagung der ÖPG, September 2005


Motivation cont d

Motivation cont‘d

  • Kaonic hydrogen / deuterium

    • Kp simplest exotic atom with strangeness

    • kaonic hydrogen „puzzle“ solved –

      but:precision data missing

    • kaonic deuterium never measured before

    • atomic physics: new cascade calculations to be tested

55. Jahrestagung der ÖPG, September 2005


Goals

Goals

Precision measurement of strong interaction shift

and width of kaonic hydrogen and kaonic deuterium

at the highest precision

  • Determination of the isospin dependent

    scattering lengths

    • no extrapolation to zero energy

  • Testing chiral symmetry breaking in systems

    with strangeness

  • 55. Jahrestagung der ÖPG, September 2005


    K p and k d atoms

    Kaonic

    atom

    e.m. position

    of K line

    (eV)

    (eV)

    (eV)

    hydrogen

    6480

     200

     250

    deuterium

    7810

     325

     630

    K-p and K-d atoms

    • K-p (K-d) e.m. bound kaonic atoms

    • Bohr radius ~80 fm

    • binding energy ~9 keV

    • strong interaction range ~1 fm

    • strong interaction treated perturbatively

    X-ray Yield

    ~1-3%

    ~0.2 %

    !

    55. Jahrestagung der ÖPG, September 2005


    Scattering lengths

    Scattering Lengths

    Relation of strong interaction shift and width

    to the complex Kp scattering length aK-p

    For the determination of the isospin dependent

    scattering lengths a0 and a1 the hadronic shift

    and width of kaonic hydrogenandkaonic deuterium

    are necessary

    But: isospin-breaking and e.m. corrections

    55. Jahrestagung der ÖPG, September 2005


    Kaonic hydrogen

    n

    4

    3

    2

    1

    Kaonic Hydrogen

    s p d f

    Negative kaons stopped in H2 initial atomic capture 

     electromagnetic cascade  X-ray transitions

    Shift and width

    of states n>1 negligible

    E2p

    Kg

    G1s

    Ka ~ 6.3 keV

    ε1s = E2p-1s(meas.) – E2p-1s(e.m.)

    E1s

    e1s

    }

    As the kaon interacts strongly with the nucleus the 1s energy level is shifted and broadened

    55. Jahrestagung der ÖPG, September 2005


    Da ne ln frascati

    DEAR

    DAΦNE (LN Frascati)

    electron – positron collider

    collision energy tuned

    to the Φresonance

    at 1.02 GeV c.m.

    55. Jahrestagung der ÖPG, September 2005


    Experimental set up

    Experimental Set-up

    APD Cryo-Cooler

    X-ray energy measurement of kaonic K lines with an array of 16 CCDX-ray detectors

    TMP

    CryoTiger

    CCD Cooling

    CCD Electronics

    Vacuum Chamber

    CCD Pre-Amp

    Target Cell

    CCD55-Chips

    kaons from Φ decay

    e+ e-

    Light-weight cylindrical target structure

    55. Jahrestagung der ÖPG, September 2005


    Ccd detector array

    CCD-Detector Array

    • 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

    55. Jahrestagung der ÖPG, September 2005


    Shielding

    Shielding

    Overall shielding factor

    of the DEAR interaction region ~ 100

    55. Jahrestagung der ÖPG, September 2005


    Dear setup at da ne

    DEAR Setup at DAΦNE

    55. Jahrestagung der ÖPG, September 2005


    Features of the experiment

    Features of the Experiment

    • Low energy (16 MeV) nearly mono-energetic (Δp/p ~ 0.1%) kaons

      from  meson decay

      (pion-induced background largely suppressed

      compared to proton accelerator, ~ factor 100)

    • Light weight cryogenic target for low X-ray background

    • Carefully chosen structure materials

      (checked by different analysis methods, e.g. XFA)

    • Optimized gas density for high X-ray yield (cryogenic gas target, 3% LHD)

    • CCD array for X-ray detection (16 CCD-55, large area 116 cm2,

      pixel analysis for background reduction, excellent energy resolution)

    • Shielding for background reduction

    • Performance verified first with kaonic nitrogen measurement

    55. Jahrestagung der ÖPG, September 2005


    Kaonic nitrogen x ray spectrum

    Kaonic Nitrogen X-ray Spectrum

    55. Jahrestagung der ÖPG, September 2005


    Results on kaonic nitrogen

    Results on kaonic nitrogen

    • 3X-ray transitions first measured

    • Extraction of the transition yields for 7-6, 6-5, 5-4

    • Impact on cascade calculations

    • Kaonic nitrogen nearly fully stripped of electrons:

      high precision measurement of the charged kaon mass possible

    • Kaon mass (test) mK- = 493.884 ± 0.314 MeV

    ΔmK- = 60 keV

    55. Jahrestagung der ÖPG, September 2005


    Resulting k p x ray spectrum

    Resulting K-p X-ray Spectrum

    X-ray energy spectrum

    with all background

    fit-components subtracted

    1s = - 193 ± 37 (stat.) ± 6 (syst.) eV

    1s = 249 ± 111 (stat.) ± 30 (syst.) eV

    55. Jahrestagung der ÖPG, September 2005


    Dear results

    attractive

    repulsive

    KpX (KEK)

    M. Iwasaki et al, 1997

    1000

    KpX

    widthG1s[eV]

    800

    • = - 323 ± 63 ± 11 eV

      G = 407 ± 208 ± 100 eV

    DEAR

    600

    Izycki et al, 1980

    400

    200

    Bird et al, 1983

    Davies et al, 1979

    0

    -500

    0

    500

    shifte1s[eV]

    DEAR Results

    55. Jahrestagung der ÖPG, September 2005


    Pr zisionsmessungen mit kaonischen atomen von dear zu siddharta

    55. Jahrestagung der ÖPG, September 2005


    Next steps

    Next Steps

    Goal: High precision X-ray spectrocopy with X-ray timing

     New X-ray detectors SDDs: JRA in I3HP (EU FP6)

    in cooperation with LNF, MPG, PNSensor, Politecnico Milan,

    IFIN-HH

    • timing capability  background suppression

      by using the kaon-X ray time correlation

    • excellent energy resolution

    • high efficiency, large solid angle

    • radiation hardness

    • compact versatile design

      New dedicated target-detector set-up

    In the next stage of the experiment we expect an improvement in the signal / background ratio of ~ 2 – 3 orders of magnitude

    55. Jahrestagung der ÖPG, September 2005


    Sdd structure

    SDD Structure

    Detector produced at the MPI Halbleiterlabor, Munich, Germany

    55. Jahrestagung der ÖPG, September 2005


    Kaon x ray coincidence

    SDDs

    e-

    e+

    Trigger scintillators not shown

    Kaon – X-ray Coincidence

    X-ray detector array : ~ 200 SDDs

    1 cm2 each

    55. Jahrestagung der ÖPG, September 2005


    Pr zisionsmessungen mit kaonischen atomen von dear zu siddharta

    Monte Carlo: K-d with SDDs

    Background

    suppression

    to < 10-3

    Kaonic deuterium

    Ag K fluorescence

    lines (calibration)

    Ka

    Kb,g

    No timing

    SDD

    ‚single‘

    Energy (keV)

    Energy (keV)

    coinc.

    SDD * Scint * Scint

    Large SDD energy resolution tested: ~ 160 eV @ Mn

    (cooling to -120°C, voltage 200V)

    55. Jahrestagung der ÖPG, September 2005


    Kaonic helium @ kek

    Kaonic Helium @ KEK

    55. Jahrestagung der ÖPG, September 2005


    Kaonic helium puzzle

    Kaonic helium "puzzle"

    Theory gives more than

    10 times smaller values

    but

    55. Jahrestagung der ÖPG, September 2005


    Kaonic l line x ray spectrum

    Kaonic L line X-ray spectrum

    Monte Carlo Simulation

    104 K-He events

    and S/B ~ 4

    e: ± 1.5 eV

    G: ± 4.4 eV

    number of events

    energy [keV]

    55. Jahrestagung der ÖPG, September 2005


    What we can learn

    What we can learn ?

    • Nature of S0(3115) state

      observed recently at KEK

    • Experimental information on

      anti-kaon – nucleon interaction

    T. Suzuki, Phys. Lett. B597(2004) 263

    55. Jahrestagung der ÖPG, September 2005


    Epilogue

    Epilogue

    "Hadronic atoms are a wonderful tool to measure

    QCD amplitudes at threshold."

    J. Gasser, Proc. DAFNE04

    "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

    55. Jahrestagung der ÖPG, September 2005


    Summary and outlook

    Summary and Outlook

    DEAR one of the first experiments at DAΦNE

    First production of exotic atoms at DAΦNE shown

    Measurements on kaonic nitrogen and finally kaonic hydrogen

    Final DEAR results on strong interaction shift and width in K-p:

    • repulsive shift in K-p verified.

    • smaller values and higher precision for shift and width.

    • Kβ, Kγ line pattern observed for the first time.

    SIDDHARTA

    Silicon Drift Detectors for Hadronic Atom

    Research by Timing Applications

    Large SDDs and new set-up in progress

    New experiments – physics program

    • Measurement of kaonic deuterium (first measurement ever)

    • Precision measurement of kaonic hydrogen (percent level).

    • Further perspectives:kaonic helium (He-3, He-4).

      Precision measurement of chargedkaon mass….

    55. Jahrestagung der ÖPG, September 2005


    Pr zisionsmessungen mit kaonischen atomen von dear zu siddharta

    On the way to new precision experiments

    SIDDHARTA

    Silicon Drift Detectors for Hadronic Atom

    Research by Timing Applications

    Thank you

    55. Jahrestagung der ÖPG, September 2005


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