Roses from the Flower Garden of Subatomic Physicspnphys/nuclth/Kienle.Nara.pdfNara WU 08.06.2005...
Transcript of Roses from the Flower Garden of Subatomic Physicspnphys/nuclth/Kienle.Nara.pdfNara WU 08.06.2005...
Nara WU 08.06.2005 Paul Kienle 1
Exotic Atoms:Roses from the FlowerGardenof Subatomic PhysicsPaul KienleStefan Meyer Institut/ÖAW Wienand TU München
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Content
• What are exotic atoms?
• Exotic atoms in hadron physics
• Pionic hydrogen atoms
• Deeply bound pionic nuclear states
• Kaonic hydrogen atoms
• Deeply bound kaonic nuclear states
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What are Atoms?
Compounds of nuclei and electrons. The negative charged electrons are bound by
the Coulomb-field of the positive charged nucleiwith a binding energy Be in the groundstate.
Be = -(Zα)² mec²/2α = e²/(ħc)mec² = 0.511 MeVRB = (ħc)/(Zα mec²)
Bohr-radius ~50.000 fm
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What are Exotic Atoms?
Replacing an electron by an „exotic“,negative particle, makes an „exotic atom“
Is the particle a „heavy electron“, i.e. amyon, one makes a myonic atom withthe binding energy Bµ
Bµ = -(Zα)² mµc²/2mµc² = 105.66 MeV,mµ ~ 200 x met1/2(µ) = 2.2 x 10-6 s
Bohr-Radius ~250 fm
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… a research area with many highlights!Myon-catalysed fusion:Catalysis of Hydrogen fusionat low temperatures
Kaonic hydrogen – puzzle:InteractionAttractive or repulsive ?
Discovery of deeply boundPionic states in heavy nuclei
Discovery of deeply bound, densekaonic clusters (strange tribaryon)
Synthesis of antimatter atoms(antihydrogen) @ LEAR-AD/CERN
ddd
nn
3He3He3HeHe
π−π−−
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• Antihydrogen, the orchidof exotic atoms (antiproton+positron)
• Nearly like hydrogen,but …..
• „Where have all the „nubars“ gone?“• Sam will look for every one.• „Where have all symmetries gone?“• CERN will search for all in one.
Antihydrogen:The Exotic Hydrogen Atom
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• Replacing an electron with negative chargedpions or kaons produces pionic or kaonicatoms, respectively.
• Pions and kaons are mesons, bound quark-antiquark systems, which show in addition toCoulomb-attraction also a strong interactionwith nuclei which can be attractive or repulsive.
Hadronic Atoms:Pionic and Kaonic Atoms
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Quarks and Gluons – the Costituents of Hadrons
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Special Properties of Hadrons
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The Problem of Hadron Masses
3 x mquark ~ 3 x 10 = 30 MeV/c²
much smaller
mnucleon ~ 1000 MeV/c² !
1 Nucleon
3 Quarks
4 Nucleons
Helium
Bound systems, such asnuclei, have smallermasses than theircostituents, the nucleons
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Spontaneous Symmetry Breaking
Buridians donkey doesit starve to death ?
Mexican Hat-Potential
No, it breaks the left-right symmetry andfinds food in the valley
Spontaneous magnetisationof a ferromagnet (Heisenberg)Chiral symmetry breaking (Nambu)
Johannes Buridian (1300-1358)
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Spontaneous Magnetization
Above Curie Point Below Curie Point
The order parameter is the magnetization: <S>≠0
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Chiral Symmetry Breaking -an every day dinner table problem
Chiral symmetric startsituation with the salad
Chiral symmetry brokensalad left, ladies right side
Chirality Handedness (Left or Right)
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Dynamic Production of Hadron Masses
Hadron-SpectrumChiral Symmetry-
Breaking
Pions Nambu-Goldstone Bosons
Quark-Condensateas Function of T, ρ
New Groundstate with
Chiral Condensate
4πfπ
<qq> = -1,5 fm-3
By spontaneous breaking of chiral symmetryinteracting particles, such as quarks, generate agroundstate with a „Chiral Condensate“, pions asNambu-Goldstone bosons, and an energy gap= 4πfπwith fπ,,the pion decay constant as order parameter.
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Pionic Hydrogen
• Pionic Hydrogen is the most elementary boundsystem to study the low energy pion–nucleoninteraction by spectroscopy of the X-raytransitions
• Measurement of the strength of the pion-nucleon interaction at threshold and comparisonwith theory (Tomozawa-Weinberg Theorem)
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Production of π-Mesonen
p+AZ = X +
PSI-Cyclotron PSI Myon-Pion-Beams
Negative Pions from PSI Cyclotron
π-
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Kα
ε1s = Enp-1s(measured) – Enp-1s(el.m.)
Pionic Hydrogen X-Ray SpectroscopyNegative Pions stopped in H2 atomic capture electromagnetic cascade X-ray transitions
ε1s
Γ1s
s p d f
E1s}
E2p
n43
2
1
Kγ
The strong pion-nucleon interaction shifts and broadens the 1s- groundstate by (ε1s) and (Γ1s), respectively.
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Pionic Hydrogen Spectroscopy @ PSI
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Hadronic Shift and Width in Pionic Hydrogen
Attractive strong interaction
Goal: Highest Precision Shift: 0.2% Width: 1%
Molecular Effects
Doppler BroadningCoulomb-Deexcitation
Stabilitity & Calibration
..
1
.
11
me
snp
meas
snps EE !! !="
Systematic studies necessary:
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S-Wave Pion-Nucleon Interaction
isoscalar
isovector
Chiral low energy-theorem(Tomozawa-Weinberg)
b0 = (–1,6 ± 1,3) x 10-3 mπ-1
b1 = (–86,8 ± 1,4) x 10-3 mπ-1
Experimental values(pionic hydrogen)
Improvement by PSI
experiment inprogress
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• Study of the low energy pion-nucleusinteraction by spectroscopy of pionic atoms
• Comparison of the interaction with the one ofpionic hydrogen
• Search for a modification of the pion-decay-constant, fπ ,a measure of spontaneousbreaking of chiral symmetry and the chiralcondensate
Pions in Nuclei
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How to Make Pionic States in Pb?
• Stopped pion– X-ray
spectroscopy
• Nuclear reaction– (d,3He) reaction
Deeply Bound States
Nuclear Absorption
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Formation of Deeply Bound StatesT. E. O. Ericson and K. Kilian
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Experimental Technique
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Pionic Sn NucleiDeeply bound pionic
1s states in123,119,115Sn clearlyobserved
0
10
20
30124
Sn(d,3He)
0 1 2 3 4 5B [MeV]
0
10
20
30120
Sn(d,3He)
0 1 2 3 4 5B [MeV]
360 365 3700
10
20
30116
Sn(d,3He)
0 1 2 3 4 5 B [MeV]
3He Kinetic Energy [MeV]
2s,2p,3d..
2s,2p,3d..
2s,2p,3d..
hydrogen peakhydrogen peak
calibration linecalibration line
Quasi-free
!- production
Quasi-free
!- production
Monotonic shift due toisotope effect
Built-in indicator ofabsolute energycalibration from Mylarbacking targets: p(d,3He)π0
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Implications on Chiral Restoration in Nuclei
( )05.078.0
2
2*
1
free
1 ±===!
"! #
f
f
b
bR
0.65 (theoretical prediction)
( )64.0
2
2
0
*
=!
! "
f
f0
6.0 !!" #
( )67.0
m
m
2
2
0
*2
*
0
0 =!""#
$%%&
'(
)
)
)
)* *
f
f
T. Yamazaki and S. Hirenzaki PLB557(2003)20
Meissner et al. Ann.Phys.297(2002)27
MeV3m2
mmm
**
*+!
+=
"+
###
#
Meissner et al. Ann. Phys.297(2002)27
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Kaonic Hydrogen
• Kaonic hydrogen serves for the study of theantikaon – nucleon interaction
• Elementary bound system with one „strange“quark
• Study of the role of „strangeness“ in the stronginteraction
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Production of K Mesons
Production of K- Mesons (DAΦNE /LNF)e- +e+ Φ K- +K+
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Kaonic Hydrogen
DEAR
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Experimental Set-up
TMP
CCD Electronics
Vacuum Chamber
APD Cryo-Cooler
Target Cell
CryoTigerCCD Cooling
CCD Pre-Amplifier
CCD55-Chips
Energy measurement ofkaonic K lines with anarray of 16 CCD X-raydetectors
volume: 1150 ccm cryogenic H2 gas fillingside walL: 75 µm Kaptonentrance window: 125 µm Kaptongrid structure: glass fiber reinforced epoxy e+ e-
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repulsive shift verifiedsmaller shift, widthsmaller error barsKβ, Kγ disentangled
Combined result for hadronic shift and width (preliminary) Shift: ε1s = - 194 ± 46 eV Width: Γ1s = 249 ± 132 eV
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DEAR Result
Wid
th Γ
1s [e
V]
KpX
-500 50000
200
400
600
800
1000
Shift ε1s [eV] D
avie
s et
al,
1979
Izyc
ki e
t al,
1980
Bird
et a
l, 19
83
repulsive attractiveKpX (KEK)M. Iwasaki et al, 1997
ε =
- 323
± 6
3 ±
11 e
VΓ
= 4
07 ±
208
± 1
00 e
V
New theoretical studies:Ivanov et al. 2003 / 2004Meißner, Raha, Rusetsky 2004
DEAR
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Antikaon-Nucleon Interaction
N. Kaiser, P.B. Siegel, W. WeiseNucl. Phys. A 594 (1995) 325
KpX
DEAR
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Antikaon in Nucleus• Search for proton rich nuclei, which are bound
by the strong K-p attractive interaction
• Antikaons are made of anti u/d-quarks and ones-quark and are not repelled by a nucleon dueto the Pauli principle (no „Hard Core“)
• High binding energies and densities expected innuclei bound by antikaons
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ppK- Bound System
- “kaonic Hydrogen molecule”
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3He K-ppn ρ(0)=0.14 ρ(0)̃1.5
B = 20 MeV B ̃118 MeV
K-K-ppnρ(0)̃3.0B ̃221 MeV
Single-K- Double-K-Dote et al. 2002
Tri Baryon Systems, 3He, K-ppn, K-K-ppn
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4He (K-,n) ppnK- 4He (K-,p) pnnK-
(K-, N) Reactions @ KEK
BK=173 MeV, Γ<20 MeV BK=194 MeV, Γ<20 MeV
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Kaonic Bound Systems with 3 Nuclei
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D-Λ- Correlations in 1.9A GeV Ni-Ni-CollisionsN. Herrmann (very preliminary)
Result: M = 3.14 GeV/c² Γ = 0.11 GeV
Al-Al collisions @ 2A GeV (with lower background) in August
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Production of ppK- in (p,d) Reactions(3.5-4.5 GeV)@GSI
Exclusive measurement of 4-momemta of 3p, 2π-, π+
in FOPI-detector of GSI
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FOPI-detector @ GSI
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Detection of K+ and Λ in 1.9A GeV Ni+Ni Collisions
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Simulation of Exclusive Detection of ppK- withFOPI
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• Exotic Atoms Precision-tools of hadron physics by new methodsand techniques
• New accelerator facilities (J-PARC, FAIR) new opportunities for studies with exotic atoms
• Studies of deeply-bound exotic states Access to new area of hadron physics
• Synthesis of superdense nuclei with 2 antikaons in HI collisions, pbar annihilation(color superconducting Quark-Gluon matter, kaoncondensation???)
Outlook and Summary
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Epilog
If these are roses , then they will bloom!