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


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


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


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


… 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−−


• 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


• 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


Quarks and Gluons – the Costituents of Hadrons


Special Properties of Hadrons


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


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)


Spontaneous Magnetization

Above Curie Point Below Curie Point

The order parameter is the magnetization: <S>≠0


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)


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.


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)


Production of π-Mesonen

p+AZ = X +

PSI-Cyclotron PSI Myon-Pion-Beams

Negative Pions from PSI Cyclotron

π-


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.


Pionic Hydrogen Spectroscopy @ PSI


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:


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


• 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


How to Make Pionic States in Pb?

• Stopped pion– X-ray

spectroscopy

• Nuclear reaction– (d,3He) reaction

Deeply Bound States

Nuclear Absorption


Formation of Deeply Bound StatesT. E. O. Ericson and K. Kilian


Experimental Technique


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


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

qq

qq

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


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


Production of K Mesons

Production of K- Mesons (DAΦNE /LNF)e- +e+ Φ K- +K+


Kaonic Hydrogen

DEAR


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-


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


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


Antikaon-Nucleon Interaction

N. Kaiser, P.B. Siegel, W. WeiseNucl. Phys. A 594 (1995) 325

KpX

DEAR


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


ppK- Bound System

- “kaonic Hydrogen molecule”


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


4He (K-,n) ppnK- 4He (K-,p) pnnK-

(K-, N) Reactions @ KEK

BK=173 MeV, Γ<20 MeV BK=194 MeV, Γ<20 MeV


Kaonic Bound Systems with 3 Nuclei


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


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


FOPI-detector @ GSI


Detection of K+ and Λ in 1.9A GeV Ni+Ni Collisions


Simulation of Exclusive Detection of ppK- withFOPI


• 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


Epilog

If these are roses , then they will bloom!

Roses from the Flower Garden of Subatomic Physicspnphys/nuclth/Kienle.Nara.pdfNara WU 08.06.2005...

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