1. Study of the kaonic nuclear clusters at DAΦNE: the AMADEUS experiment
Dorel Pietreanu
LNF - INFN, Via. E. Fermi 40, Frascati (Roma), Italy
On behalf of the AMADEUS Collaborations
LNF Spring School “Bruno Touschek”, May 15th-19th, 2006
LNF Spring School “Bruno Touschek”, May 2006

2. Antikaonic Matter At DAFNE: an Experiment Unraveling Spectroscopy
LNF Spring School “Bruno Touschek”, May, 2006

3.            information concerning a modification of the kaon mass and of the KN interaction in the nuclear medium => interesting and important from the viewpoint of spontaneous and explicit symmetry breaking of QCD            information on a transition from the hadronic phase to a quark-gluon phase => changes of vacuum properties of QCD and quark condensate            kaon condensation in nuclear matter => implications on astrophysics: neutron stars, strange stars nuclear dynamics under extreme conditions (nuclear compressibility, etc) could be investigated
Important impacts in fundamental physics
LNF Spring School “Bruno Touschek”, May, 2006

4. Exploring dense nuclear states
with K- bound states
LNF Spring School “Bruno Touschek”, May, 2006

5. Current and future planned experiments
FINUDA at DAFNE
KEK: E549 - to confirm the existence of the two strange tribaryons observed in E471
E570
J-PARC (LOI06; LOI10) – K-induced reaction in flight
GSI (FOPI) – nucleus-nucleus and proton –nucleus collision
LNF Spring School “Bruno Touschek”, May, 2006

6. Y. Akaishi & T. Yamazaki, Phys. Rev. C 65 (2002) 044005
First experimental indications: E471 Experiment Results
4He(K-stopped, n) and 4He(K-stopped, p) missing mass spectra
(M. Iwasaki et al., nucl-ex/ v2)
S0(3115): M = (sys)+/-0.9 (stat)
G< 21.6 MeV,
B= -194 MeV with respect to K-+p+n+n rest mass
Predicted NOT to exist! (B~20 MeV; G~100 MeV)
S+(3140): M = (sys)+/-2.3 (stat)
G< 21.6 MeV,
B= -169 MeV with respect to K-+p+p+n rest mass
Predicted with B ~ 110 MeV
M. Iwasaki et al., NIM A 473 (2001) 286
Y. Akaishi & T. Yamazaki, Phys. Rev. C 65 (2002)
LNF Spring School “Bruno Touschek”, May, 2006

7. Production mechanisms of DBKNS:
1) Stopped K- reactions on light nuclei, with ejection of a proton or a
neutron as spectators
2)  In-flight K- reactions:
- Knock-out reactions (K-, N) where one nucleon is knocked out in the formation stage;
- (K-, π-) reactions in proton-rich systems to produce exotic bound nuclear states on unbound systems.
3) Protons (3.5 – 4.5 GeV) on a deuteron target for the production of K–pp detected in a 4 detector.
4) The identification of clusters as residual fragments (“K fragments”) in heavy ion collisions via the invariant mass of their decay products.
Identification and study of DBKNS:
- Formation -> missing mass
Decay > invariant mass
-> Spectroscopy!
LNF Spring School “Bruno Touschek”, May, 2006

8. Features of the experimental setup
The complete study of the characteristic features of the kaonic bound nuclear systems requires knowledge of: binding energy, level width and partial widths, angular momentum, isospin, sizes, densities, etc.
This can be done by simultaneously observing the production stage of the K--clusters via missing mass spectroscopy, and their decay products since their momentum correlations contain information on the internal structure of the exotic system.
It is therefore necessary to use a 4π dedicated detector capable of detecting all particles created in both the formation and decay of the K-clusters.
LNF Spring School “Bruno Touschek”, May, 2006

9. K- + 4He -> n + (K-ppn) np- Ld Lpn S0pn S-pp pp- (~64%) Lg
Features of the experimental setup
The decay process
K- + 4He -> n + (K-ppn)
np- Ld
Lpn
S0pn
S-pp
pp- (~64%) Lg
np0 (~36%)
pp-
np0
n(~500 MeV/c)
2pnp-
2p;n;g;p-
1p;2n;p0;g
2p;n;p-
1p;2n;p0
p;d;p-
n;d;p0
LNF Spring School “Bruno Touschek”, May, 2006

10. Features of the experimental setup
Decay process
The exotic states are expected to predominantly decay into final states containing  and S hyperons and protons, neutrons, deuterons or larger systems of nucleons. The most important feature of a detector is therefore the reconstruction capability for  and S hyperons from the invariant mass of their decay into nucleon +  and/or g.
This implies good particle identification for these particles and their decay products.
From this data, frame-invariant Dalitz plots can be constructed, which
are expected to reflect the size and density of the initial exotic state.
LNF Spring School “Bruno Touschek”, May, 2006

11. The KLOE detector The detector satisfying all these features =>
Performance of the KLOE 4p detector:
fully checked and exploited in the numerous measurements done already by KLOE;
studies of processes with BR of < (10-6)
acceptance 96%
DC: sp/p ~ 0.4%
Spatial resolution of vertices in DC: 3 mm
dE/dx capacity for particle ID implemented
ECAL dE/Eg ~ 5.7%/E1/2
st= (54/E1/2 + 50) ps
Ks->p+p- at 0.8 MeV/c2
p0 mass resolution to 2-3 % (reconstruction)
Resol. for n of 500 MeV/c ~ 3%
LNF Spring School “Bruno Touschek”, May, 2006

12. AMADEUS integration in KLOE: first drawing
EMC
KLOE –
Drift Chamber
Possible setup
for AMADEUS
within KLOE:
Cryogenic target
Inner tracker
Kaon trigger
LNF Spring School “Bruno Touschek”, May, 2006

13. Preliminary design: AMADEUS setup at KLOE
LNF Spring School “Bruno Touschek”, May, 2006

14. AMADEUS Experimental programme
Measurements to be performed:
The most fundamental system which we plan to study are the kaonic dibaryon states of ppK- and npK-, which are favorable produced using a 3He gas target in 3He(K-, n/p) reactions.
Their masses including their total width will be determined by neutron and proton energy measurements respectively. Exclusive measurements of their decays allow to extract further information:
size/density, angular momentum, ...
A similar programme is planned for kaonic 3-baryon states, populated in reactions using a 4He gas target.
Furthermore we plan to extend these studies systematically over a broad range of nuclear targets starting by Li, B and Be.
LNF Spring School “Bruno Touschek”, May, 2006

15. http://www. lnf. infn. it/esperimenti/siddharta/LOI_AMADEUS_March2006
LNF Spring School “Bruno Touschek”, May, 2006

16. Thank you!
LNF Spring School “Bruno Touschek”, May, 2006

17. 3He ---> 3HeK- shrinkage !!
rc ~ r0
Explore cold
and dense
nuclear states
(Dote et al. 2002)
LNF Spring School “Bruno Touschek”, May, 2006

18. Features of the experimental setup
Formation process:
K- + 4He -> p + (K-pnn); p ~ 550 MeV/c
K- + 4He -> n + (K-ppn); n ~ 510 MeV/c
Exotic nuclear states in light nuclei produced with (K-, N) reactions at rest will be observed by the energy distribution of the ejected protons and neutrons via the missing mass spectra of the (K-, p) and (K-, n) reactions.
The setup should be capable to measure:
Outgoing protons up to 600 MeV/c
Outgoing neutrons up to 600 MeV/c
in a 4π acceptance detector, with good efficiency and resolution.
LNF Spring School “Bruno Touschek”, May, 2006

19. Pre-experiment: PROPOSAL to KLOE
First actions towards AMADEUS
Pre-experiment: PROPOSAL to KLOE
The DC of KLOE  seen as an active target (4He) where
=> some K- stop => DBKNS DC
K-pnn K- p
LNF Spring School “Bruno Touschek”, May, 2006

20. Pre-experiment: PROPOSAL to KLOE
First actions towards AMADEUS
Pre-experiment: PROPOSAL to KLOE
A preliminary Monte Carlo simulation shows that with 2 fb-1 one might have due to K- stopped in the He gas of the DC:
> 1500 events of
-> the BEST measurement in the world
> 500 events of
AMADEUS group -> willing to help KLOE in
data analysis
K- + 4He -> p + (K-pnn); p ~ 550 MeV/c
K- + 4He -> n + (K-ppn); n ~ 510 MeV/c
LNF Spring School “Bruno Touschek”, May, 2006

21. K-ppn  ° + d p + - K-ppn  ° + p + n p + -
Pre-experiment: PROPOSAL to KLOE
4He + K-  K-ppn + n
K-ppn  ° + d
p + -
K-ppn  ° + p + n
p + - d n - n p - p - p
energy [MeV]
LNF Spring School “Bruno Touschek”, May, 2006

22. AMADEUS Experimental programme
By observing momentum correlation in the three-body decay channel, such as
pppK-  +p+p or
ppnK-  +p+n,
one will get information, using the correlation pattern in the Dalitz plane, of the size, density and the angular momentum of the involved kaonic cluster.
 all decay products have to be identified
 their 4-momenta have to be determined
LNF Spring School “Bruno Touschek”, May, 2006

23. Conclusions
As far as the experimental setup is concerned, the 4p KLOE detector, implemented for AMADEUS program, operated in DAFNE2, satisfies the requirements to study the characteristic features of the K-nuclear clusters, which must consists both in observing the production stage of a K-nuclear clusters and detecting the decay products.
DANE2 can become the world-scientific pole to study the K- induced processes at rest, which were indicated as the more direct way to investigate the clusters in nuclear matter.
First steps towards the realization:
Monte Carlo intensive simulations
Measurement (KLOE+SIDDHARTA) of KLOE calorimeter
for n-efficiency
Feasibility of AMADEUS in KLOE
Possibility to participate to KLOE2 – new parts
LNF Spring School “Bruno Touschek”, May, 2006

24. Kaonic nuclear clusters: short introduction
Features and identification of the setup and the experimental programme
First steps towards AMADEUS
Conclusions
LNF Spring School “Bruno Touschek”, May, 2006

25. LNF Spring School “Bruno Touschek”, May, 2006