Testing Λ (1405) with K-mesic atoms

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Wycech, Meson- 2010 Testing Λ(1405) with K- mesic atoms S.Wycech IPJ, Warsaw The purpose Λ(1405) is the dorway and the mechanism to bind the „K-mesic nuclei”

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Testing Λ (1405) with K-mesic atoms. S.Wycech IPJ, Warsaw The purpose Λ (1405) is the dorway and the mechanism to bind the „K-mesic nuclei”. Two approaches to Λ (1405). Phenomenology K – matrix fitted to data + dispersion relations Extrapolation below KN , E ~ 1405 MeV - PowerPoint PPT Presentation

Transcript of Testing Λ (1405) with K-mesic atoms

Page 1: Testing  Λ (1405) with K-mesic atoms

Wycech, Meson- 2010

Testing Λ(1405) with K-mesic atoms

S.Wycech IPJ, Warsaw

The purpose

Λ(1405) is the dorway and the mechanism to bind the „K-mesic nuclei”

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Wycech, Meson- 2010

Two approaches to Λ(1405)

• Phenomenology K – matrix fitted to data + dispersion relations Extrapolation below KN , E ~ 1405 MeV PDG, R.Dalitz, A.Martin.. many others since 1970

▪ Chiral models SU(3) symmetric driving force , pole in Σπ,

pole in KN plane , E ~ 1420 MeV W.Weise, E.Oset .. others since 2000

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Experimental check

K N Σπ below threshold in final states

not conclusive

provides amplitude a(K N,Σπ) no a(K N,KN)

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Wycech, Meson- 2010

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Two new (?) suggestions to extract KN amplitudes from

1) Upper atomic levels 2) Atomic nuclear radiative transitions

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„upper levels „

s p d …. n= 3 n= 2 „ upper ” n= 1 „ lower „

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Upper levels „do not fit „

E. Friedman , A.Gal Im a= 0.37 fm upper levels Im a= 0.94 fm lower levels

Г ~ Im a (KN, E = - EBINDING - ERECOIL )

5 - 25 % accurate in upper levels impulse approx. not valid in lower levels

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Wycech, Meson- 2010

Nucleon levels „seen” in atoms

V(r) radial distance

lower upper levels

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Parallel case, antiprotonic atoms Nuclear regions studied in atomic levels

lower upper cold capture ↓ ↓ ↓

ρ(r)

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Wycech, Meson- 2010

P-bar N subthreshold energies involved in p-bar atoms

-40 -20 0 MeV

• P

• D

T He 4

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Wycech, Meson- 2010

Im a(E) extracted from light antiprotonic atoms - PS 207 data

Paris model

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Im aKN(E) extracted from upper widths

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Im a(KN) extracted from upper widths

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Favorite situation for studying Г(upper): one or few nucleon orbitals

perfect P,D,He, very good Li, Be, C, N,O, resonable in almost all atoms

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K-neutron dominated widths

Upper widths due mostly to Kn , S + P wave

Pb Im a (K – n)

Apparently dominated by Σ(1385)

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Wycech, Meson- 2010

Another possibility to study sub-threshold elastic KN or K-nucleus amplitude

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Wycech, Meson- 2010

K-hydrogen Λ(1405 ) + γ

Kaons lost in cascade Kaonic Hydrogen ~ 95% lostHow many go to Λ(1405 ) + γ ?

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Old BNL experiment K – p Σ(1190) γ

Found on the level of 1/1000 D.A.Whitehouse ..PRL.63(89)1352; K.D.Larsen.. Phys.Rev D47(93)799

K – p Λ(1405) γ

Is it feasible ?What is the line shape ?

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High energy photons from K- p atom

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Gamma rays to Λ(1405)

5 10-3 of captures from ( n P) levels

s p d n= 3 n= 2 n= 1

Λ(1405)

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Occupation and capture from all (n,P) states

estimated captures from n P states in gas targets~ few % of stopped K mesons

Total chance for γ transition ~ 0.001-0.0001per stopped kaon

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Kaonic deuterium atom KNN

Deep state ~100 MeV ( FINUDA, DISTO) Very small chance

Weakly bound or virtual state ~ 47 MeV P+Σ(1385) sw Phys. Rev C 79 Good chance

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Line shape

Г = ∫ dk S(k)

S(k) = Im TKN,KN (Eo–k) k GKN(k)

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LINE SHAPE resonance●propagator●phase space

Σ π

T

GKN γ

p K-

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Summary Upper widths in K atoms may determine Im TKN,KN (M K + MN – E ) for E = 0 - 40 MeV

K -Atom K-Nuclear + γ may give elastic Im TKNUCLEUS(M K + MN – E )

Experiments are difficult

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Upper levels –suggestions

Interesting measurements • He (2p )• Be , C , repetition • Sn 112,116,118,124 – different proton

bindings Pb 208 Kn parameters in addition to D