Study%20of%20the%20kaonic%20nuclear%20clusters%20at%20DAFNE:%20the%20AMADEUS%20experiment

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Study of the kaonic nuclear clusters at
DAFNEthe AMADEUS experiment

• Dorel Pietreanu
• LNF - INFN, Via. E. Fermi 40, 00044 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
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AntikaonicMatterAtDAFNE anExperimentUnraveli
ngSpectroscopy
LNF Spring School Bruno Touschek, May, 2006
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          information concerning a modification
of the kaon mass and of the KN interaction in the
nuclear medium gt 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 gt changes of vacuum properties
of QCD and quark condensate           kaon
condensation in nuclear matter gt 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
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Exploring dense nuclear states with K- bound
states
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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
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First experimental indications E471 Experiment
Results 4He(K-stopped, n) and 4He(K-stopped, p)
missing mass spectra
(M. Iwasaki et al., nucl-ex/0310018 v2)
S0(3115) M 3117 3.8-2.0(sys)/-0.9 (stat) Glt
21.6 MeV, B -194 MeV with respect to
K-pnn rest mass Predicted NOT to exist! (B20
MeV G100 MeV)

S(3140) M 3117 3.8-2.0(sys)/-2.3 (stat) Glt
21.6 MeV, B -169 MeV with respect to
K-ppn 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)
044005

LNF Spring School Bruno Touschek, May, 2006
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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-, p-) 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 Kpp 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 -gt missing mass
• Decay -gt invariant mass
• -gt Spectroscopy!

LNF Spring School Bruno Touschek, May, 2006
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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 4p 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
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Features of the experimental setup
The decay process

LNF Spring School Bruno Touschek, May, 2006
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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.


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• The detector satisfying all these features gt
• The KLOE detector
• Performance of the KLOE 4p detector
• fully checked and exploited in the numerous
  measurements done already by KLOE
• studies of processes with BR of lt 10-3 (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-gtpp- 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
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AMADEUS integration in KLOE first drawing
KLOE EMC
KLOE Drift Chamber
Possible setup for AMADEUS within
KLOE Cryogenic target Inner tracker Kaon trigger
LNF Spring School Bruno Touschek, May, 2006
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Preliminary design AMADEUS setup at KLOE
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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.


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• http//www.lnf.infn.it/esperimenti/siddharta/LOI_A
  MADEUS_March2006.pdf

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Thank you!
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3He ---gt 3HeK- shrinkage !!
rc 4 -10 r0

• Explore cold
• and dense
• nuclear states

(Dote et al. 2002)
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Features of the experimental setup
Formation process
K- 4He -gt p (K-pnn) p 550 MeV/c
K- 4He -gt 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 4p acceptance detector, with good efficiency
  and resolution.

LNF Spring School Bruno Touschek, May, 2006
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First actions towards AMADEUS
Pre-experiment PROPOSAL to KLOE The
DC of KLOE ? seen as an active target (4He)
where gt some K- stop gt DBKNS
DC

K-pnn
K-
p

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• 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
• gt 1500 events of
• -gt the BEST measurement in the world
• gt 500 events of
• AMADEUS group -gt willing to help KLOE in
• data analysis

K- 4He -gt p (K-pnn) p 550 MeV/c

K- 4He -gt n (K-ppn) n 510 MeV/c

LNF Spring School Bruno Touschek, May, 2006
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Pre-experiment PROPOSAL to KLOE
4He K- ? K-ppn n
K-ppn ? ? d
p ?-
K-ppn ? ? p n
p ?-
n
d
?-
n
p
?-
?-
p
p
energy MeV
LNF Spring School Bruno Touschek, May, 2006
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AMADEUS Experimental programme By observing
momentum correlation in the three-body decay
channel, such as pppK- ? ?pp or ppnK- ?
?pn, 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


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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 (KLOESIDDHARTA) of KLOE calorimeter
• for n-efficiency
• Feasibility of AMADEUS in KLOE
• Possibility to participate to KLOE2 new parts

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