View
35
Download
0
Category
Preview:
DESCRIPTION
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
Citation preview
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”
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
Wycech, Meson- 2010
Experimental check
K N Σπ below threshold in final states
not conclusive
provides amplitude a(K N,Σπ) no a(K N,KN)
Wycech, Meson- 2010
Wycech, Meson- 2010
Two new (?) suggestions to extract KN amplitudes from
1) Upper atomic levels 2) Atomic nuclear radiative transitions
Wycech, Meson- 2010
„upper levels „
s p d …. n= 3 n= 2 „ upper ” n= 1 „ lower „
Wycech, Meson- 2010
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
Wycech, Meson- 2010
Nucleon levels „seen” in atoms
V(r) radial distance
lower upper levels
Wycech, Meson- 2010
Parallel case, antiprotonic atoms Nuclear regions studied in atomic levels
lower upper cold capture ↓ ↓ ↓
ρ(r)
Wycech, Meson- 2010
P-bar N subthreshold energies involved in p-bar atoms
-40 -20 0 MeV
• P
• D
•
T He 4
Wycech, Meson- 2010
Im a(E) extracted from light antiprotonic atoms - PS 207 data
Paris model
Wycech, Meson- 2010
Im aKN(E) extracted from upper widths
Wycech, Meson- 2010
Im a(KN) extracted from upper widths
Wycech, Meson- 2010
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
Wycech, Meson- 2010
K-neutron dominated widths
Upper widths due mostly to Kn , S + P wave
Pb Im a (K – n)
Apparently dominated by Σ(1385)
Wycech, Meson- 2010
Another possibility to study sub-threshold elastic KN or K-nucleus amplitude
Wycech, Meson- 2010
K-hydrogen Λ(1405 ) + γ
Kaons lost in cascade Kaonic Hydrogen ~ 95% lostHow many go to Λ(1405 ) + γ ?
Wycech, Meson- 2010
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 ?
Wycech, Meson- 2010
High energy photons from K- p atom
Wycech, Meson- 2010
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)
Wycech, Meson- 2010
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
Wycech, Meson- 2010
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
Wycech, Meson- 2010
Line shape
Г = ∫ dk S(k)
S(k) = Im TKN,KN (Eo–k) k GKN(k)
Wycech, Meson- 2010
LINE SHAPE resonance●propagator●phase space
Σ π
T
GKN γ
p K-
Wycech, Meson- 2010
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
Wycech, Meson- 2010
Wycech, Meson- 2010
Wycech, Meson- 2010
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
Recommended