AMADEUS

1
AMADEUS
Antikaon Matter At DA?NEExperiments with
Unraveling Spectroscopy
32nd Meeting of the LNF Scientific
Committee 31st May 1st June 2006
C. Guaraldo
2
Contents

• Introduction
• The case of AMADEUS
• The framework of the AMADEUS Proposal
• Realizing AMADEUS
• Determination of the neutron detection efficiency
  of the KLOE e.m. calorimeter
• Implementation of the AMADEUS setup within KLOE
• Analysis of the Helium data of the KLOE Drift
  Chamber
• Conclusions

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1. Introduction
4
Letter of Intent
Study of deeply bound kaonic nuclear states at
DA?NE2 AMADEUS Collaboration
March 2006
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111 scientists from 33 Institutes of 13 Countries
signed the Letter of Intent
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2. The case of AMADEUS
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The case of AMADEUS

• Problem

How the spontaneous and explicit chiral symmetry
breaking pattern of low energy QCD changes in the
nuclear environment
How the hadron masses and interactions changes in
the nuclear medium

• Approach
• New type of in-medium hadron mass
  spectroscopy
• Method
• Producing deeply bound states from which to
  deduce the hadron-nucleus potential and the
  in-medium hadron mass

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Deeply bound pionic atoms
Successful example of deeply bound mesonic states
Deeply bound states in pionic atoms
T. Yamazaki, P. Kienle et al., Z. Phys. A355
(1996) 219
Subtle balance at the surface of a heavy nucleus
between the Coulomb attraction and the repulsion
resulting from the pion-nuclear strong
interaction.

• Important tool for testing chiral pion-nucleus
  dynamics and studying partial chiral
  symmetry restoration

W. Weise, Acta Phys. Pol. B31 (2000) 2715 P.
Kienle and T. Yamazaki, Phys. Lett. B514 (2001)
1 P. Kienle, T. Yamazaki, Progress in Particle
and Nuclear Physics 52 (2004) 85.
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Deeply bound kaonic nuclear states

• Deeply bound kaonic nuclear states in presence
  of a strong KN attractive potential were
  firstly suggested by Wycech S. Wycech,
  Nucl. Phys. A450 (1986) 399c
• A new paradigm in strangeness nuclear physics
  can be considered the work Nuclear bound
  states in light nuclei by Y. Akaishi and
  T. Yamazaki Phys. Rev. C65 (2002) 044005

Strong attractive I0 KN interaction favors
discrete nuclear states bound100-200 MeV and
narrow 20-30 MeV shrinkage effect of a K on
core nuclei
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The KN interaction

• Deeply bound kaonic nuclear states require the
  presence of a
• strong attractive KN interaction in the
  isospin I0 channel
• However, apparently, from experiments
• S-wave K- nucleon scattering length is
  negative at threshold ? repulsive type
  interaction
• A.D. Martin, Nucl. Phys. B179 (1981) 33
• K? line shift of kaonic hydrogen is negative
  ? repulsive type interaction
• KEK M. Iwasaki et al., Phys. Rev. Lett. 78
  (1997) 3067 DEAR G. Beer et al., Phys.
  Rev. Lett. 94 (2005) 212302

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Results on the shift and width for kaonic hydrogen
DEAR results G. Beer et al., Phys.Rev.Lett. 94,
(2005) 212302 ?1s - 193 37(stat) 6(syst)
eV ?1s 249 111(stat) 30(syst) eV
X-ray energy (keV)
klk
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In-medium effects on the dynamics of the ? (1405)

• If the s-wave, isospin I0 ?(1405) resonance is
  dominantly a KN bound state ? the actual K-p
  interaction is attractive although it appears
  repulsive in the scattering length and the K?
  energy shift of kaonic hydrogen

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In-medium effects on the dynamics of the ? (1405)
influence of the nuclear medium on ?(1405)
formation

• strong non-linear density dependence of optical
  potential repulsion in free space attraction
  in nuclear matter
• this comes from experiments result of a
  systematic phenomenological re-analysis of kaonic
  atoms data E. Friedmann, A. Gal and C.J. Batty,
  Phys. Lett. B308 (1993) 6 Nucl. Phys. A579
  (1994) 518.
• mechanism Pauli principle on proton weakening
  of binding ? ?(1405) mass shift up to threshold

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Influence of the nuclear medium (Pauli blocking)
on the formation of the ?(1405)
T. Waas, N. Kaiser, W. Weise, Phys. Lett. B 365
(1996) 12
In free space, at threshold, point A, aK-plt0 ?
repulsive interaction In nuclear matter at rather
low density (?0.2 ?0), at threshold, point B,
aK-pgt0 ? attractive interaction
B
A
K- p threshold
1432
Fig. 1. Real (dashed lines) and imaginary parts
(solid lines) of the K- p scattering amplitude in
nuclear matter at different values of the Fermi
momentum pF (3p2 ?/2)1/3, as a function of the
total c.m. energy vs . a) free space, pF 0
b) 0.2 ?0, pF 150 MeV/c c) 1.4 ?0,
pF 300 MeV/c ?0 0.17 fm-3
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Role of a bound state below threshold

• The behavior of the K-p potential is a
  phenomenon well known in nuclear physics
• Simple arguments from low-energy scattering show
  that the existence of a bound state below
  threshold always leads to a repulsive scattering
  length.M.A. Preston and R.K. Badhuri, Structure
  of the nucleus, Addison-Wesley, Reading,
  Massachusetts, 1974
• Analogy between the K-p scattering in the I0
  channel and the proton-neutron (p-n) scattering
  in the deuteron channel (I0, S1)
• the interaction between the proton and
  neutron is attractive, but the scattering length
  in the deuteron channel (I0, S1) is repulsive,
  due to the existence of the deuteron as a bound
  state. In nuclear matter, however, the deuteron
  disappears, largely due to Pauli blocking, and
  the true attractive nature of the p-n interaction
  emerges.

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3. The framework of the AMADEUS Proposal
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The framework of the AMADEUS Proposal

• Experiments
• Present KEK E471, E549, E570 DA?NE
  FINUDA GSI FOPI
  analyses of the recently collected data are in
  progress
• Future new data from FOPI, FINUDA and JPARC
• Theory
• Debate in progress, including alternative
  interpretations of the data so far obtained
• - Another kaonic hydrogen puzzle like
  story?until new reliable experimental results
  are on the market?

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AMADEUS philosophy/ strategy

• The only way to confirm, or deny, the exotic
  states is to perform a good measurement
  using a high performance detector on the
  most suitable accelerator

a measurement NOT performed until now
complete determination of all formation and decay
channels
binding energies, partial and total widths,
angular momenta, isospin, sizes, densities, etc
? Detection of charged particles, neutrons and
photons up to about 800 MeV/c in 4?
geometry Requirements satisfied by the
performance of the KLOE detector
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4. Realizing AMADEUS
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Realizing AMADEUS

• determination of the neutron detection
  efficiency of the KLOE e.m. calorimeter
• Implementation of the AMADEUS setup within
  KLOE
• Analysis of the KLOE Drift Chamber Helium data

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5. Determination of the neutron detection
efficiency of the KLOE e.m. calorimeter
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Strange tribaryon formation

• K- 4He ? (ppnK-) n

The (pnnK-) kaonic cluster may decay through the
following channels   (ppnK-) ? L d ? L
np ? S- pp ? S0 d ? S0 np   with
the L and Ss decaying according to PDG.
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Range of interest of neutron energies
The ejected primary neutrons in the formation
process (monochromatic component) have a
momentum of about 510 MeV/c (energy about 140
MeV).
Neutrons produced in the tribaryon decay channel
Lpn (continuous component) have momenta
starting from few tens MeV/c till about 600
MeV/c (energy about 180 MeV)
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Determination of the KLOE calorimeter efficiency
for neutrons

• MonteCarlo simulations AMADEUS MonteCarlo
  GEANT simulation (and FLUKA MonteCarlo from KLOE)
• Measurement with a neutron beamKLOEAMADEUS
  experimental test of a prototype of the KLOE
  calorimeter on the neutron beam of TSL (Uppsala)
  KLONE proposal

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A prelimnary GEANT MonteCarlo simulation of the
KLOE calorimeter extraction of the efficiency
for neutron detection

• AMADEUS Technical Note IR-1, 4 March 2006
• M. Cargnelli
• STEFAN MEYER Institute for Subatomic Physics,
  Vienna, Austria 
• C. Curceanu
• Laboratori Nazionali di Frascati dellINFN,
  Frascati, Italy

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KLOE calorimeter
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The calorimeter MC model
One quarter of the calorimeter was modelled, the
azimuthal angle 0-90 degrees was subdivided in 6
modules. Each module consisted of a lead
converter with an inner radius of 200 cm and
23 cm width. The total length was 4,3 m. In these
6 volumes the fibres were placed as copies of
cylindrical volumes with 1 mm diameter, by taking
the tangential pitch of 1.35 mm and the radial
pitch of 1.2 mm.
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GEANT 3.21 simulation - inputs
The neutrons were started isotropically from the
centre of the apparatus (the beam interaction
point). The neutron momentum was sampled
uniformly between 100-1300 MeV/c. The sum of
deposited energies in the fibres (starting from 0
no signal generated) of one module was
histogrammed versus the incoming neutron energy.
The ratio of the number of neutrons depositing
energy versus the total number of incoming
neutrons gives the intrinsic efficiency.
The values are given for 2 lower thresholds of
the deposited energy 3 and 1 MeV. Only signal
produced by protons was taken into account.
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GEANT 3.21 simulation example of events
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GEANT 3.21 simulation example of events
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MonteCarlo simulation - Calorimeter response
Neutron detection efficiency
Threshold at 1 MeV Threshold at 3 MeV
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Results in agreement with FLUKA dedicated
simulations performed by KLOE. Refined
MonteCarlo simulations to understand details
(topology, etc.) are undergoing.


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Measurement of the neutron efficiency using a
test beam
Test of a calorimeter prototype on a neutron
beam KLOE AMADEUS, mixed team of 15
persons, lead by Stefano Miscetti
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The KLONE proposal at TSL (Uppsala)
KLONE (KLOe NEutrons) formal request to TSL in
April 2006 Stefano Miscetti and Catalina
Curceanu Funded with European Transnational
Access budget of TSL within the FP6
HadronPhysics Project
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• The KLOE calorimeter prototype for KLONE
• dimensions 25 x 13 x 60 cm3, instrumented
  on both sides (32 PMs in total)
• cut from a prototype of the KLOE calorimeter

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(No Transcript)
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The TSL neutron beam at Uppsala (1)
Neutrons are produced in the Blue Hall of TSL by
the 7Li(p,n) reaction. The proton beam can be
varied in the 20-180 MeV range. The resulting
neutron energy distribution is such that half of
the neutrons are concentrated within 1-2 MeV, at
few MeV below the incident proton energy. The
remaining neutrons are roughly equally
distributed in energy from zero up to the maximum
neutron energy. After passage through the
production target, the proton beam is deflected
in a magnet and dumped far away from the testing
area to minimize background.


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The TSL neutron beam at Uppsala (2)
Neutrons emitted in the forword direction pass
through a collimator consisting of iron rings of
various diameters, such that any neutron beam
diameter from zero up to 30 cm, in steps of 5 cm,
can be accomplished. The testing position can be
chosen anywhere from just after the collimator up
to 10 m away from it (where the neutron beam is
130 cm diameter). The neutron beam facility is
equipped with a fission based monitor, which
provides a flux measurement with 10 absolute
precision.


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Blue Hall at TSL and neutron beam

KLONE setup

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Performed actions

• 15-16 May 2006 visit at TSL and discussions with
  TSL staff for details
• checked the beam quality compatibility with the
  goal of the measurement OK
• checked the geometry of Blue Hall and possible
  positioning of setup OK
• checked the control room availability OK
• assured participation and support from TSL staff

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• KLONE Project at TSL
• - approved on 18/05/2006 ? code F183 assigned
• - beam time allocated in October 2006week 42
  and 43
• in Frequency Modulation (FM) mode (100-180 MeV
  energy range)

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Future working plan

• Preparation of the KLONE setup will start
  in July (when setup at disposal)
• Test of the setup at LNF until October
  2006 optimization
• October 2006 transportation and
  measurements at TSL

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6. Implementation of the AMADEUS setup within KLOE
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AMADEUS setup within KLOE
KLOE EMC
KLOE Drift Chamber
Possible setup for AMADEUS within
KLOE Cryogenic target Inner tracker Kaon trigger
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AMADEUS setup

• There are presently 2 versions
• without a vertex/inner tracking detector
  (minimal version)
• - with a vertex/inner tracker detector

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The kaon trigger

• The same in both versions with half toroidal
  cryogenic target
• optimal solution for a kaon trigger system,
  consisting of
• two cylindrical inner-layer scintillating fibres
  detectors x-y position within
  1mm due to an angle of 60 between the two
  layers
• three half cylindrical outer-layer scintillating
  fibres detectors
• with inner and outer scintillating fibres layers
  a track reconstruction is possible,
  therefore with the magnetic field of
  KLOE K and K- are distinguishable

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AMADEUS setup-minimal version
(with the collaboration of Vincenzo Patera)
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We need the position of the K- stop primary
vertex Then the kaon tracker might be essential
(under study) Second version of AMADEUS setup
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AMADEUS setup- second version (in collaboration
with KLOE - for vertex detector)
KLOE and AMADEUS had few meetings in which the
vertex/inner tracking detector was discussed A
common solution is emerging location of the
detector in such a way that both KLOE and AMADEUS
can use it Technical solutions (type of
detector) and plans for prototyping and testing
are being discussed and under evaluation


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AMADEUS setup- second version (in collaboration
with KLOE - for vertex detector)

• A tracking/vertex detector (a Time Projection
  Chamber (TPC) with GEM-readout in this example)
  is surrounding the half toroidal cryogenic target
  cell with the (previous) kaon trigger
  configuration.
• Alternative, if the background rate is too high
  (to be checked with FINUDA inner-tracker) a
  multi-layer cylindrical GEM detector is in
  discussion might be necessary
  

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AMADEUS setupsecond version
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AMADEUS setup- second version(in collaboration
with KLOE - for vertex detector)

• In case of low background it is possible to use a
• full toroidal cryogenic target cell
• In this case, the kaon trigger is made of
• two inner-layers of scintillating fibres
• x-y determination due to the crossing of the
  fibre-layers with an angle of 60
• two outer-layers of scintillating fibres
• x-y determination due to the crossing of the
  fibre-layers with an angle of 60
• additional fast timing information for charged
  particles background suppression for inner
  tracking detector (TPCGEM)

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AMADEUS setup with full toroidal cryogenic target
cell
vacuum chamber
kaon trigger 2 inner-layer of scintillating
fibre fiber size 1x1mm2
full toroidalcryogenic target cell
thin-walled beam pipe
2 outer-layer of scintillating fibre fiber size
1x1mm2
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Cryogenic toroidal target cell working
temperature 5 -10 K working pressure lt 2
bar thin-walled design 75µm Kapton, with
aluminum grid reinforcement
(grid transmission gt 85 ) inner
diameter 110 mm outer diameter
210 mm inner length 120 mm
outer length 200 mm
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Results of preliminary MonteCarlo simulations for
AMADEUS setup with optimized degrader and
cryotarget
peak luminosity
3 10-30 cm2 F production cross
section
0.49 branching ratio for K
production rate for charged kaon pairs
R L s b 1500 s-1
produced K per month 31 108 (80 duty
cycle assumed)
1033 cm-2s-1
40 are stopped in the cryogenic He gas target
(15 liq. He density, 5 cm thick) ? 12.5 108
K- 4He atoms per month

• for 10-3 cluster formation yield 12.5
  105 kaonic clusters formed in one month
• Efficiency of tracking identification K
  detection of decay products ? 105 events per
  month ( 1000 pb-1)

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7. Data analysis of 2 fb-1 KLOE data
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Data analysis of the 2 fb-1 KLOE data to search
for kaonic nuclear clusters produced in the
reaction 4He(K-stopped, nucleon)


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E471 KEK results 4He(K-stopped, p) and
4He(K-stopped, n) missing mass spectra


M. Iwasaki et al., nucl-ex/0310018 v2
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Pre-experiment Proposal to KLOE

• Preliminary Monte Carlo simulations shows that
  with 2 fb-1 one might have
• gt 1500 K- stopped events in Helium of KLOE Drift
  Chamber, of the type
• and gt 500 events of the type
• AMADEUS group ? 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
(assuming en 30)

31th LNF Scientific Committee
CC,JZ / Nov. 29, 2005
60

What happened in the last months

• Refined MCarlo simulations with the AMADEUS code
• AMADEUS officially accepted in the Kcharged group
  of KLOE
• Mixed team KLOE-AMADEUS got formed and started to
  work
• Training of AMADEUS team by the KLOE Kcharged
  team
• KLOE MCarlo dedicated production and start
  analysis
• Plan for data analysis

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KLOE detector
Schematic side view of the KLOE detector
K
e-
e
The drift chamber is filled with He
isobutane at atmospheric pressure He as active
volume
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Reaction channels (simplified)
F
K
K-
K- 4He
p
m
p-
m-
ppnK n
pnnK p
L d
L n p
S- p p
S0 d
S0 n p
L n n
S- n p
S- d
S0 n n
L g
n p-
n p0
p p-
Measure 1 particle of a 2-body decay. Transform
to cms of the decaying Object. Gives 2nd
particle properties. Missing mass spectroscopy
g g
Measure all outgoing particles to obtain
the total cms energy invariant mass of the
object
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Monte Carlo simulation 100000 events


P(p-) GeV/c
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AMADEUS MonteCarlo to get the K- stopped in
Helium of DC
(blue) dotted line for gammas (red) solid
line for charged particles (except muons) (black)
blank/dotted line for neutral hadrons or
neutrinos (green) dashed line for muons (yellow)
dotted line for Cerenkov photons
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K- stopped in Helium
KLOE Drift chamber
K entering chamber
K- stopped in the chamber
K- stopped in the chamber
Events / bin
z-position (mm)
radial-position (mm)
z beam direction collision zone sz 30 mm
0.3 stopped in the gas of the chamber
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AMADEUS MonteCarloK-clusters in existing KLOE
data
Total number of produced charged kaon pairs for
L 2 fb-1
3 10-30 cm2 F production cross
section
0.49 branching ratio for K
2 fb-1 2 1039 cm-2 integrated
luminosity
N L s b 2.9 109

• 0.3 stopped in the gas of the chamber
• 3 10-3 2.9 109 8.8 106 K- 4He atoms
• For a cluster yield of 10-3 we have 8800
  clusters
• Without efficiency of tracking identification
  of K/- detection of decay products

Kaon production rate 150 K- s-1 (for L
1032 cm-2 s-1 )
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AMADEUS officially accepted in the K charged team
of KLOE

• A group of 5 persons from AMADEUS
• Paul Buehler
• Michael Cargnelli
• Catalina Curceanu
• Dorel Pietreanu
• Diana Sirghi
• started to work under the supervision and in
  strict contact with Vincenzo Patera and Erika De
  Lucia (Kcharged team of KLOE)

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Start working on analysis (1)

• 13-15 March 2006 training course for AMADEUS
  team held by KLOE (Vincenzo Patera Erika de
  Lucia)
• Overall view of KLOE and its data stream
• Presentation of the Monte Carlo and the real
  data structure
• Dedicated Monte Carlo production strategy
  modified from
• KLOE MCarlo
• Exercises to better understand the process
• Start elaborating a strategy of MCarlo analyses
• Moreover, a dedicated afs area on KLOE computing
  farm, under KLOE Kcharged group, was created for
  these analyses.

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Start working on analysis (2)

• Actions
• Start dedicated MonteCarlo Ntuple production (10
  million of events)
• Start to learn how to treat the data in order to
  obtain the final number of stopped kaons
  optimization of the strategy of data analysis and
  learn how to treat the final data (how to tag,
  what to ask in order to have enhanced recognition
  of the kaonic nuclear clusters, efficiencies,
  background, etc.)

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Preliminary results

• 0.3 K- stopped in the gas of the chamber
• 3 10-3 2.9 109 8.8 106 K- 4He atoms
• For a cluster yield of 10-3 we have 8800
  kaonic clusters
• Taking into account
• Efficiency of tracking identification K
  detection of decay products ?
• 1000-2000 reconstructed kaonic clusters

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Future plans

• Finalize KLOE dedicated MCarlo analysis and
  implement the dedicated kaonic cluster physics
  (from AMADEUS MCarlo)
• Start preliminary analysis of the final data (on
  a small data set) in order to understand
  background and to calibrate the strategy of
  overall data analysis
• Start massive real data analyses in strict
  contact and under the supervision of KLOE team,
  as soon as data will be available for analyses

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7. Conclusions
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Conclusions (1)

• The AMADEUS Collaboration aims to perform the
  most complete experimental effort ever done so
  far in searching for deeply bound kaonic nuclear
  clusters using, for the first time, a 4?
  dedicated detector capable of detecting all
  charged and neutral particles created in both
  formation and decay of kaonic clusters.
• The goal is to definitely clarify their
  debated existence.

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Conclusions (2)

• 2. To realise the programme, the AMADEUS setup -
  cryogenic target, kaon trigger, vertex/inner
  tracker - must be implemented within the KLOE
  detector. The use of the KLOE calorimeter as
  neutron detector is as well compelling and
  implies the determination of the neutron
  detection efficiency.
• 3. A successful collaboration between the KLOE
  and AMADEUS teams has been already established
  and a common work is in progress. Conditio sine
  qua non for the realization of the programme.