exotic atoms/nuclei t. yamazaki, riken

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EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN • Yukawa mesons (1935) • Anderson PR51(1937), Nishina PR52(1937): muon • Tomonaga-Araki, PR58(1940): mesonic atom form ation • Fermi-Teller (1947) Strong-interaction shifts of pion: Jenkins et al. (1966) • Ericson-Ericson (1966), Tomozawa-Weinberg (19 66) Deeply bound pions: Toki-Yamazaki (1988) First observation (1996)

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EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN. Yukawa mesons (1935) Anderson PR51(1937), Nishina PR52(1937): muon Tomonaga-Araki, PR58(1940): mesonic atom formation Fermi-Teller (1947) Strong-interaction shifts of pion: Jenkins et al. (1966) - PowerPoint PPT Presentation

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Page 1: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

EXOTIC ATOMS/NUCLEIT. Yamazaki, RIKEN

• Yukawa mesons (1935)• Anderson PR51(1937), Nishina PR52(1937): muon• Tomonaga-Araki, PR58(1940): mesonic atom formation• Fermi-Teller (1947)• Strong-interaction shifts of pion: Jenkins et al. (1966)• Ericson-Ericson (1966), Tomozawa-Weinberg (1966)• Deeply bound pions: Toki-Yamazaki (1988)• First observation (1996)

Page 2: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Exotic Resonance States of Antiprotons, Pions and Kaons in Atomic and Nuclear Systems

Toshimitsu Yamazaki, RIKEN

• Hadronic systems --> strong nuclear absorption --> short-lived, no discrete states• Exceptions: long-lived, discrete states in continuum: Energy spacing >Width• --> High-precision spectroscopy• Feshbach resonances: Bound states of X-

embedded in continuum

Exotic atoms/nuclei Negative pions Negative kaons Antiprotons

Page 3: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Hadron-Nucleus Bound-State SpectroscopyToshimitsu Yamazaki (RIKEN)

• Explore Chiral Symmetry Restoration in Nuclear Media Brown-Rho scaling:

• HOW TO MEASURE In-medium hadron masses and interactions in well defined states and densities??

• POPULAR METHODS: Invariant-mass spectroscopy for decay particles in continuum medium

• NEW METHOD: Bound-state spectroscopy: IF hadron bound states exist with narrow widths?

How? Suppression mechanisms for nuclear absorption? Pionic Nuclei (1988 -): observed (1996,1998,2001), matured Kaonic Nuclei (2000 -): predicted, no observation yet

Page 4: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Deeply Bound Pionic States1s pionic states in heavy (N>Z) nuclei

• Shallow pionic atoms: • Last orbital: ~1-10 keV• Deeply bound states:

~ 0.5 MeV ~ 5 MeV Still discrete states!!Coulomb attraction + Strong Interaction Repulsion

----->> Halo like pionic states (absorption suppressed)E. Friedman and G. Soff (1985)H. Toki et al. (1988): --->> pion transfer reactions First success: (d, 3He) at GSI

Page 5: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

New Frontiers of Exotic Atoms/Nuclei

From outside to inside * atomic states of X radiative transitions from outer orbitals * terminated cascade

From inside to outside* nuclear resonance states* still bound states of X

EXOTIC ATOMS/NUCLEI

Page 6: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Pion-Nucleus Potential Parameters

s-wave p-wave

Light 1s states in symmetric nucleiSeki-Masutani relation

Double-scattering effect

Page 7: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Pionic Bound States Probe Nuclear Surface

Overlapping density:

maximum at

The density-dependent potential parameter:

is transposed to

S(r) = ρ(r) | Φ (n,l) |2 r 2

b1(ρ(r)) =b1

( free )

1−α ρ(r)

b1* =

b1( free )

1−α ρeff

ρ(r) ⇒ ρeff ≈ 0.60 ρ (0)

Page 8: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

  in   205Pb

Page 9: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Sn(d,3He) spectraK. Suzuki et al., PRL (2003)

Page 10: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

PIONIC NUCLEI as a unique indicator of Chiral Symmetry Restoration

in the nuclear mediumFundamental building blocks:• Nuclei: protons (938 MeV) + neutrons (940 MeV) + virtual mesons (pion: 140 MeV; etc.)• Hadrons: quarks + gluons: u (~ 5 MeV), d (~ 8 MeV), s (~ 150 MeV) Surprising discrepancies -->> ascribed to quark condensate in QCD vacuum: order parameter of chiral symmetry breakingQCD vacuum is subject to change: partial restoration of chiral symmetryHOW to prove or disprove this scenario? As in superconductors Pion decay constant in medium ---> Isovector pion-N interaction

  b1(free) /b1*(ρ) -->>

Page 11: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

B1s and 1s in Sn Isotopes

Page 12: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Pionic Bound States as an Indicator of Chiral Symmetry Restoration

Isovector s-wave interaction --->> pion decay constant in the

mediumWeise (2000, 2001)Kienle and TY (2001)

Best probe: Pionic 1s inheavy nuclei

GSI experiment on pionic 115Sn, 119Sn, 123Sn K. Suzuki et al. (2002)

Page 13: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Evidence for partial restoration of chiral symmetry in nuclear medium probed by 1s pionic nuclei (2003)

isoisoso

Isovector s-wave N scattering length

Page 14: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Hadron Bound States

Page 15: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Nuclear excited states with strangeness S = -1as Feshbach resonances

p, n(940)

: stable Hypernuclei: Many observed,,

Hypernuclei: Unstable: conversio

n Exception: 4

He405: K-p bound stateK-N(1433)

K- nuclear bound states?

Page 16: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Akaishi KN PotentialY. Akaishi and TY, PRC (2002)

Page 17: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Diagram Kaon Bound System

Page 18: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

ppK- bound system

- kaonic hydrogen nuclear molecule

Page 19: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

K- potentials and bound states

• Y. Akaishi and TY, PRC (2002)• TY and Y. Akaishi, PLB (2002)

Page 20: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Shrinkage effect: Competition between

K-p attraction and nuclear incompressibility

Page 21: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

3He ---> 3HeK- shrinkage !!

Antisymmetric Molecular Dynamics Method

IsovectorDeformation Dote et al.

Page 22: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Very exotic systemskaonic tri-protons

kaonic tetra-protons

Page 23: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Kaonic Be-8: Contracted Alpha Cluster Dote et al. (2002)

Page 24: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

(K,) and (,K) reactions for various K- bound systems

* Large q: good for large internal momentum* Varieties (K-,-) (-,K0) (+,K+) (,K0) Q -1 0 +1 targetp * +, +*[n] - * +, +* d pnK- ppK- -3He ppnK- pppK- -4He ppnnK- pppnK- ppppK-

Page 25: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Experimental SearchM. Iwasaki et al., at KEK

4He (stopped K-, n)K- 3He

Page 26: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

-doorway and -compound mechanisms T. Yamazaki and Y. Akaishi, PLB 535 (2002) 70

Hepp et al., N.P. B 115 (1976) 82

Page 27: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

K- Compound Nuclei 1520 + p + n +…. ---> K- + p + p + n

+…

• ---> K- bound state +

Page 28: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Predicted (K-,-) Spectra Y. Akaishi

Page 29: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

How about ppK-K-, ppnK-K- ??

Page 30: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

total B.E. = 221 MeVcentral density = 3.01 fm-3

rmsR= 0.69 fm

ppnK-K-

total B.E. = 118 MeVcentral density = 1.50 fm-3

rmsR= 0.72 fm

total B.E. = 6.0 MeVcentral density = 0.14 fm-3

rmsR= 1.59 fm

Double kaonic nucleus // ppnK-K- //

ppnK- ppn

Density [fm-3]0.0 1.5 3.0

Density [fm-3]0.00 0.75 1.50

Density [fm-3]0.00 0.07 0.14

4 fm 4 fm 4 fm

Page 31: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Kaonic Nuclei - Future Scope

Very strong K--p attraction • Very deep discrete states: predicted B

K ~ 100 MeV

• Highly excited resonance states• In-medium KN interactions modified?• Dense nuclear systems formed Possibly, Quark-Gluon phase at T = 0• Kaon condensation; strange matter• Nuclear dynamics under extreme conditions

Page 32: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Strangeness at high nuclear densities

The nuclear incompressibilityis overcome by the Strong K- p attraction

At high density K- matter

[K- p] + [K- p] + …+ n +… may be more stable

Page 33: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Spectroscopy

** Entrance channel spectroscopy Direct reactions: A+a --> X + b Missing-mass spectroscopy

** Decay channel spectroscopy Compound reactions --> X + anything X --> x1 + x2 + … Invariant-mass spectroscopy: Minv

2 = (E1 + E2 +..)2 - (P1 + P2 + ..)2

Page 34: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Search for K- cluster fragments in HI reactionshigh-density environment provided by HI fireball

Invariant mass spectroscopy for their decaysK-pp --> + p, K-ppn --> + d

Page 35: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN
Page 36: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN
Page 37: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Kbar cluster decay in the freeze-out phaseK (=10 fm/c) > freeze-out

Page 38: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

FOPI from Kusche (PhD) 1999

Page 39: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

FOPI from Kusche (PhD) 1999

Page 40: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN
Page 41: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN
Page 42: EXOTIC ATOMS/NUCLEI T. Yamazaki, RIKEN

Search for K- clusters as residues in heavy-ion reactions

• High density medium accommodated in fire balls

• Deep self-trapping centers in fire balls• Freeze-out phase• Invariant mass spectroscopy for fragments

ppK- ---> + p ppnK- ---> + d