new high precision experiments on kaonichydrogen and ... · pdf filenew high precision...

New high precision experiments on kaonic hydrogen and helium atoms

J. MartonStefan Meyer InstituteAustrian Academy of Sciences, Viennahttp://www.oeaw.ac.at/smiEmail: [email protected]

22.5.2008 1Seminar, Institut für Kern‐ und Teilchenphysik, TU Dresden, May 22, 2008

Outline

• Exotic atoms: unique research field

• In more detail ‐ kaonic atoms

• Status of kaonic hydrogen

• Breakthrough with new x‐ray detectors

• New measurements at DAΦNE (LNF/Italy)• Future possibilities

• Summary

22.5.2008 Seminar, Institut für Kern‐ und Teilchenphysik, TU Dresden, May 22, 2008 2

Subatomic physics at SMI

Seminar, Institut für Kern‐ und Teilchenphysik, TU Dresden, May 22, 2008

Kaon‐Nucleon Interaction:

Kaonic atoms and kaonic nuclei

Matter ‐ antimatter symmetry: ASACUSA @ CERN

Antiprotons at FAIR

SIDDHARTA@LNFE17 @ J‐PARC

FLAIR

22.5.2008 3

Where our experiments are performed


LNF / Frascati, ItalyAD at CERN / Switzerland

FAIR Darmstadt, Germany

J‐PARC Tokai‐mura / Japan

PSI / Switzerland

GSI Darmstadt, Germany

22.5.2008 4

EXOTIC ATOMS

Kaonic atoms

(K‐p, K‐d, K‐3,4He)

Seminar, Institut für Kern‐ und Teilchenphysik, TU Dresden, May 22, 200822.5.2008 5

Introduction: Hadronic atoms

Seminar, Institut für Kern- und Teilchenphysik, TU Dresden, May 22, 2008

• Exotic atom: Coulomb bound system in which an electron issubstituted by a heavier particle like a lepton (muon), a meson(pion, kaon) or a baryon (antiproton)

• Different properties: Binding energy Bn and Bohr radius rB

• Life time: examples pion 26 ns, kaon 12 ns, pbar∞• Strong interaction with the nucleus: Pion, kaon, antiproton

hadronic atoms

modification due to higher reduced mass µex

22.5.2008 6


Simplest atoms with/without strangeness: pionic/kaonic hydrogen

Orbiting pion/kaon bosons

Energy levels calculated using Klein‐Gordon equation

Precision requires refinement (e.g. vacuum polarisation, finite size …)

e-p π-p K-pMass of orbiting particle

0.51 MeV/c2 139.57 MeV/c2 493.68 MeV/c2

Life time oforbiting particle

> 4.6 ·1026 yr 2.60 ·10-8 s 1.24 ·10-8 s

Bohr radius 52 900 fm 222 fm 84 fm

Binding energy 13,6 eV 3240 eV 8610 eV

22.5.20087

Exotic atoms – an unique laboratory

• Studies of fundamental interactions and symmetries


K‐p, K‐dπ‐p, π‐d….

22.5.2008 8

Research fields• Hadronic atoms –unique laboratory for studying strong interaction

at lowest energies• X‐ray spectroscopy

• Low‐energy meson‐nucleon and – nucleus interaction scattering lenghthsPionic hydrogen: vacuum values of scatt. lengths a+, a‐ (b0, b1)„calibration“ for studying in‐medium modificationsKaonic hydrogen/deuterium: KN scatt. Lengths, Lambda(1405)Kaonic helium: strong interaction on n=2 stateInformations about deeply bound states

• Particle mass determination: mass of charged kaon K‐


Most interesting kaonic atoms – simple systems:

• Z=1 kaonic hydrogen / kaonic deuterium

• Z=2 kaonic helium (3He, 4He)

Kaonic atoms – atomic systems withstrangeness

Seminar, Institut für Kern- und Teilchenphysik, TU Dresden, May 22, 200822.5.2008 10

Kaonic atoms of hydrogen isotopes


Kaonic hydrogen X‐ray spectrum (K transitions)KpX, DEAR/LNFHigh precision measurement SIDDHARTA

Kaonic deuterium X‐ray spectrum (K transitions) first time measurement by SIDDHARTA planned

Kaonic tritiumNo project (extremely difficult)

K-p and K-d atom properties


*) A.N. Ivanov, M. Cargnelli, M. Faber, H. Fuhrmann, V.A. Ivanova, J. Marton, N.I. Troitskaya, J. Zmeskal, Eur.Phys.J. A 23 (2005) 79

**) Estimated value

K‐p (K‐d) e.m. bound kaonic atomsBohr radius ~80 fm, binding energy ~9 keV

Kaonic atom

e.m. position

of Kα line(eV)

ε(eV)

hydrogen 6480 ≈ 200

deuterium 7810 ≈ 325*

Γ(eV)

≈ 250

≈ 630*

X‐ray YieldKα

~1‐3 %

~0.2 %**

22.5.2008 12

X‐ray transition energies (e.m.)


Kaonic hydrogen

Kaonic deuterium

T. Ishiwatari (SMI)

22.5.2008 13

Negative kaons stopped in H2 initial atomic capture electromagnetic cascade X‐ray transitions


Experimental method

Ka ~ 6.3 keV

ε1s = E2p‐1s(meas.) – E2p‐1s(e.m.)

E2p‐1s(e.m.) = 6479 eV

ε1s

Γ1s

s p d f

E1s}

E2p

n43

2

1

Kγ

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

Shift and width of states n>1 negligible

22.5.2008 14


Kaonic hydrogen

„By using the non-relativistic effective Lagrangian approach a complete expressionfor the isospin-breaking corrections can be obtained; in leading order parameter-free modified Deser-type relations exist and can be used to extract scattering lengths from kaonic atom data“ (Meißner, Raha, Rusetsky, 2004)

)(21

41222

10

123

aaa

aeVfmai

pK

pKpK

+=

⋅⋅==Γ

+

−

−−−μαε

With a0, a1 for the I=0,1 S-wave KN scattering lengths in the isospin limit (md = mu), μ being the reduced mass of the K-p system,and neglecting isospin-breaking corrections:

Deser‐type formula

22.5.2008 15


Kaonic deuterium

For the determination of the isospindependent scattering lengths a0 and a1the hadronic shift and width ofkaonic hydrogen and kaonic deuteriumare necessary

Theoretical procedures are needed toconnect the observables with theisospin-dependent scattering lengths

22.5.2008 16

• The low‐energy KN interaction is neither simple norwell understood (resonances)

• Sources of experimental information:• Scattering data• Inelastic reactions• X‐ray data


KN interaction at threshold

KN interaction at threshold


B. Borasoy, R. Nißler and W. Weise, Phys. Rev. Lett. 94, 213401 (2005)

K‐p: repulsive at threshold, attractive below threshold

threshold

DEAR data

real part

Imag. part

Reviewing first kaonicatoms @ DAΦNE: DEAR


DAΦNE (LN Frascati)

electron – positron collider

collision energy tunedto the Φ resonance @ 1.02 GeV c.m.


DEAR

22.5.2008 20

SIDDHARTA

Setup at DAΦNE


X‐ray detection by CCDs


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

22.5.2008 22

Resulting K‐p X‐ray Spectrum


ε1s = - 193 37 (stat.) ± 6 (syst.) eVΓ1s = 249 111 (stat.) ± 30 (syst.) eV

22.5.2008 23

DEAR Results


-500 50000

200

400

600

800

1000

shift ε1s [eV]

Dav

ies e

t al,

1979

Izyc

ki e

t al,

1980

Bird

et a

l, 19

83

width

Γ 1s[eV]

KpX

repulsive attractiveKpX (KEK)M. Iwasaki et al, 1997

ε=

-323

±63

±11

eV

Γ=

407

±20

8 ±

100

eV

DEAR

22.5.2008 24

Experiments vs.Theory


DEAR

KpX

TH1

TH2

TH3

TH1: U.G. Meißner et al.,Eur. Phys. J. C 35 (2004)349

TH2: B. Borosoy et al.,Phys. Rev. Lett. 94 (2005) 213401

TH3: SMI‐TU ViennaA.N. Ivanov et al., Eur. Phys. J. A21 (2004) 11J. Phys. G 31 (2005) 769Eur. Phys. J. A25 (2005) 329

22.5.2008 25

Conclusion


Precision data are urgently needed

22.5.2008 26

From DEAR to SIDDHARTA• Precision of the DEAR result limited by high soft X‐ray background (S/N ~ 1:70)

• Next step: background reduction by using

kaon – X‐ray time correlation

(S/N ~ 10:1 for kaonic hydrogen)


New X‐ray detectors SDDs: JRA in I3HP (EU FP6)in cooperation with LNF, MPG, PNSensor, Politecnico Milan, IFIN‐HH

and new dedicated target‐detector set‐up

22.5.2008 27

SIDDHARTA Collaboration

M. Bazzib, G. Beerc, L. Bombellid, A.M. Bragadireanub;e,M. Cargnellia, M. Catittib, C. Curceanu (Petrascu)b;e, C. Fiorinid, T. Frizzid,F. Ghiof , B. Girolamif , C. Guaraldob, R.S. Hayanog, M. Iliescub;e, T. Ishiwataria , M. Iwasakih, P. Kienlea;i, P. Lechnerj , P. Levi Sandrib, A. Longonid, V. Lucherinib,J. Martona, D. Pietreanub, T. Pontae, D.L. Sirghib;e, F. Sirghib;e, H. Soltauj ,L. Strüderk, H. Tatsunog, O. Vazquez Doceb, E. Widmanna, J. Zmeskala

a Stefan‐Meyer ‐Institut für subatomare Physik, Vienna, Austriab INFN, Laboratori Nationali di Frascati, Frascati (Roma), Italyc Dep. of Phys. and Astro., Uni. of Victoria, Victoria B.C., Canadad Politechno di Milano, Sez. di Elettronica, Milano, Italye IFIN‐HH, Magurele, Bucharest, Romaniaf INFN Sez. di Roma I and Inst. Superiore di Sanita, Roma, Italyg Univ. of Tokyo, Tokyo, Japanh RIKEN, The Inst. of Phys. and Chem. Research, Satiama, Japani Tech. Univ. München, Phsik Dep., Garching, Germanyj PNSensors GmbH, M¨unchen, Germanyk MPI for Extraterrestial Physics, Garching, Germany


New x‐ray detectors

• Silicon Drift Detectors (SDDs) are opening theway to new high precision measurements

• SDDs combine excellent energy resolutionwith timing capability and versatile design.

• The potential of SDDs for hadronic atomresearch was shown in the K‐4He experimentperformed 2005 at KEK/Japan for the firsttime.


Silicon Drift Detector SDD


Large area SDD (SIDDHARTA) with 1 cm2 active area3 SDDs on 1 chip

SDD has small capacitance low noise deviceGood energy resolution comparable with CCDs But: timing capability

22.5.2008 30

SDD Spectroscopy test• Energy spectrum of Fe‐55 x rays

• SIDDHARTA SDDs at T = ‐60 °C, τ = 1 µsecw

40

/s0

1

w4

5/

s03

w4

9/

s01


Time Resolution of SDDs

• SIDDHARTA SDD• Measurement with

tagged e- beam (BTF @ LNF)


events

22.5.2008 32

SIDDHARTA Setup


Triple coincidence: SDDX * ScintK * ScintK

Scintillator

Scintillator

D2 gas

SDD

e+

e-

Φ

K+

K-

X-ray

Triple coincidence: SDDX * ScintK * ScintK

Scintillator

Scintillator

D2 gas

SDD

e+

e-

Φ

K+

K-

X-ray

SDD array

Cryogenic setup

SDD unit (2x3x3 SDDs)

22.5.2008 33

Start‐up configuration: miniSIDDHARTA

Installation at „KLOE“ intersection:last week

New beam pipe

Reduced X‐ray detection system: 12 SDDs (3x4)

First step: Kaonic nitrogen (high yield)

Kaonic nitrogen: 4000 X‐ray eventsin ~3days [30 pb‐1], Φ~0.0054 LD

Test performance of SDDs in beamand background suppression


SIDDHARTA‐Day1


Gas target

SIDDHARTA SDDs(4x3)

TMP

Target coolingSDD cooling

HV‐ andvoltage supplyfor SDDs andreadout electronics


SIDDHARTA apparatus – full setup

22.5.2008 36


SIDDHARTA setup @ DAΦNE

22.5.2008 37

DAΦNE Upgrade


L 1033 cm‐2 s‐1

22.5.2008 38

DAFNE tuning at present


Peak luminosity up to > 2x1032

electron/positron current

Integrated luminosity/day > 6 pb‐1

2 x 107 Φ/day

Status April 14,2008

First KN lines


Kaonic Nitrogen / Day-1

4.0 6.0 8.0 10.0 12.0 14.00

10

20

30

40

50

60

70

80

Energy [keV]

Mn Ka

Cu Ka

KN 7-6

KN 6-5

KN 5-4

I.L. = 15 pb-1


SIDDHARTA - Goals

• Measurement of strong interaction shift and width of kaonic hydrogen and kaonic deuterium at the highest precision (percent level)

• Determination of the isospin‐dependent scattering lengths near threshold

• no extrapolation to zero energy (advantage over scattering experiments)

• Testing chiral symmetry breaking in systems with strangeness


• Tuning of setup / optimization 100 pb‐1

• Precision measurement of kaonic hydrogen 400 pb‐1

• Measurement of kaonic deuterium 600 pb‐1


SIDDHARTA: Schedule

22.5.2008 43

SIDDHARTA Monte Carlo Simulations


Coun

ts

Energy [keV] Energy [keV]

K‐pK‐d

Kα KβKγ

Khigh

Monte Carlo simulated X‐ray spectra (180 pb‐1)

K‐p: ε1s = 193 eV, Γ1s = 249 eV, Y(Kα )=2%Δ ε1s ∼ ±2 eV, Γ1s ∼ ± 4,5 eV

K‐d: ε1s = 325 eV, Γ1s = 630 eV, Y(Kα )=0.2%Δ ε1s ∼ ±15 eV, Γ1s ∼ ± 40 eV

22.5.2008 44

Energy [keV]

SIDDHARTA ‐ Outlook


width

Γ 1s[eV]

KpX

-500 50000

200

400

600

800

1000

shift ε1s [eV]

Dav

ies e

t al,

1979

Izyc

ki e

t al,

1980

Bird

et a

l, 19

83

KpX (KEK)M. Iwasaki et al, 1997

ε=

-323

±63

±11

eV

Γ=

407

±20

8 ±

100

eV

DEAR

SIDDHARTA

22.5.2008 45

The impact of the SIDDHARTA K‐p measurements


Breakthrough in low‐energy KN phenomenology

One order of magnitude in the precision of the K‐p scattering length

Possibility of discriminatingtheoretical approaches and methods of analysis

22.5.2008 46

Open issues

• L line spectrum of kaonic hydrogen isotopes

• Complicated due to low energy

• In principle from the yield of L and K lines the hadronic width of the 2p state accessible by experiment


Kaonic helium


Kaonic helium‐4E570 (KEK)

Kaonic helium‐3E17 (J‐PARC)

Kaonic helium "puzzle"


Experiments:2p strong interaction shift

‐43 ± 8 eV

Theory:2p strong interaction shift

~ 0 eV(≤ 11 eV Y. Akaishi)

Old puzzle (~30 years!):Large discrepancy between results from theory and experiments

Kaonic helium: past experiments


• First use of large area silicon‐drift detectors (SDDs) in exoticatom research

• Careful calibration and treatment of systematics

K‐4He experiment at KEK


Results


• Kaonic nuclear clusters: 2p shift in K4He, K3He sensitive to potential

• Crucial information for the isospin dependent antikaon‐nucleus strong interaction

Motivation K3He expt.


Kaonic helium: Outlook

• K3He X‐ray spectrum (Balmer transitions) will be measured at J‐PARC 2009 (first time measurement in a day‐1 experiment, E17)

• Liquid 3He target

• x‐ray detectors: SDDs

• Precision shift ~2 eV (stat.)


Future possibilities

• Mass of charged kaon

• Spectroscopy of kaonic atoms


Δm = 60 keV discrepancy about 6σ

Kaonic atoms with high Z problematic:Electron screening, vacuum polarisation …

Feasibility study with DEAR

• Kaonic nitrogen X‐ray transitions (not influenced by strong interaction)


X‐ray detectors of ultrahigh energyresolution


Crystal spectrometry? Cryogenic detectors –TES?

G. Beer et al., Physics Letters B 535 (2002) 52–58

ΔE/E ~ 25 eV @ 6keV Δm/m ~ 10 keV

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