AMADEUS: status and plans Catalina Curceanu, LNF - INFN on behalf of the AMADEUS Collaboration 33 rd LNF SC meeting, November 2006 AMAD EU nraveling S A ntikaon M atter A t D A  NE: E xperiments with U nraveling S pectroscopy

Contents 1.Introduction 2.The (enriched) case of AMADEUS 3.The framework of the AMADEUS Proposal 4.Towards AMADEUS realization 5.Determination of the neutron detection efficiency of the KLOE e.m. calorimeter: KLONE experiment 6.Implementation of the AMADEUS setup within KLOE 7.Progress in the analysis of the Helium data of the KLOE Drift Chamber 8.Conclusions

1. Introduction

Letter of Intent Study of deeply bound kaonic nuclear states at DA  NE2 AMADEUS Collaboration March scientists from 33 Institutes of 13 Countries signed the Letter of Intent

2. The (enriched) case of AMADEUS

The case for AMADEUS  Problem How the spontaneous and explicit chiral symmetry breaking pattern of low energy QCD changes in the nuclear environment  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 How the hadron masses and interactions change in the nuclear medium

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) Strong attractive I=0 KN interaction favors discrete nuclear states bound MeV and narrow MeV shrinkage effect of a K on core nuclei

Prediction of Lightest Kaonic Nuclear Systems

The KN interaction In-medium effects on the dynamics of the  (1405) Influence of the nuclear medium (Pauli blocking) on the formation of the Λ(1405) Role of a bound state below threshold C. Guaraldo talk at 32 LNF-SC

The scientific case of the kaonic nuclear clusters was discussed in dedicated meetings and Workshops + seminars (at LNF: S. Wycech; B. Borasoy): Exotic hadronic atoms, deeply bound nuclear states and antihydrogen: present results and future held at ECT* (Trento), on June 19-24, 2006 IVth International Conference on Quarks and Nuclear Physics (QNP06) Madrid, June 5th-10th 2006 IX International Conference on Hypernuclear and Strange Particle Physics October 2006, Johannes Gutenberg-Universität Mainz

modification of the kaon mass and of the KN interaction in the nuclear medium spontaneous and explicit symmetry breaking of QCD transition from the hadronic phase to a quark-gluon phasevacuum properties of QCD and quark condensate kaon condensation astrophysics (neutron stars, strange stars) nuclear dynamics under extreme conditions - information concerning the modification of the kaon mass and of the KN interaction in the nuclear medium => interesting and important from the viewpoint of the spontaneous and explicit symmetry breaking of QCD - information on the 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 in astrophysics (neutron stars, strange stars) - nuclear dynamics under extreme conditions (nuclear compressibility, etc) could be investigated Kaonic Nuclear Clusters contribution to fundamental physics

The enriched case of AMADEUS: Low energy KN and K-Nucleus physics

+all present to ECT* Workshop +“EURIDICE: The Final Meeting. Effective theories of colours and flavours: from EURODAPHNE to EURIDICE” Kazinierz, Poland, August 24-27, 2006

3. The framework of the AMADEUS Proposal

The framework of the AMADEUS Proposal  Experiments Present: KEK E471, E549, E570 DA  NE FINUDA GSI FOPI others (old-Dubna…) analyses of the recently collected data are in progress Future: new data from FOPI, FINUDA, JPARC (-->E15), FAIR(?)  Theory -Debate in progress, including alternative interpretations of the data so far obtained until new complete experimental results are available

Summary of the Search for Deeply Bound Kaonic States ?

AMADEUS design considerations  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

4. Realizing AMADEUS

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

5. Determination of the neutron detection efficiency of the KLOE e.m. calorimeter => KLONE experiment

P(p) GeV/c P(  ) GeV/c P(n) GeV/c Neutrons produced in the tribaryon decay channel  pn (“continuous” component) have momenta starting from few tens MeV/c till about 600 MeV/c (energy about 180 MeV) The ejected primary neutrons in the formation process (“monochromatic” component) have a momentum of about 510 MeV/c (energy about 140 MeV). Range of interest of neutron energies

Neutron detection efficiency of the KLOE calorimeter Barbara Sciascia’s talk at this Committee

KLONE calorimeter efficiency Preliminary results High efficiency in agreement with MCarlo simulation results (AMADEUS and FLUKA)

Conclusions from KLONE for AMADEUS %The measured “global” “n” efficiency for the KLOE calorimeter for 1 – 4 MeV thresholds, ranges between %  Confirms the assumption made in the AMADEUS LOI for the proposed scientific program

6. Implementation of the AMADEUS setup within KLOE

KLOE – EMC KLOE – Drift Chamber Possible setup for AMADEUS within KLOE: Cryogenic target Inner tracker Kaon trigger AMADEUS setup within KLOE

There are presently 2/3 versions: - without a vertex/inner tracking detector (minimal version) - with a vertex/inner tracker detector AMADEUS setup

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

half-toroidal cryogenic target cell 1 st inner-layer of scintillating fiber fiber size: 1x1mm 2 2 nd inner-layer of scintillating fiber fiber size: 1x1mm 2 three outer-layers of scintillating fiber fiber size: 1x1mm 2 AMADEUS setup-minimal version (with the collaboration of Vincenzo Patera)

We need the position of the K - stop = primary vertex Then the kaon tracker might be essential (under study in collaboration with KLOE) Second version of AMADEUS setup

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

Technical solutions (type of detector and readout electronics) and plans for prototyping and testing are being discussed and under evaluation 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 AMADEUS setup- second version (in collaboration with KLOE - for vertex detector)

two TPC sections with triple GEM and x-y readout on both sides kaon trigger made of 2+3 scintillating fibers layers, inside a vacuum chamber half-toroidal cryogenic target cell vacuum chamber thin-walled beam pipe AMADEUS setup second version

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 fiber-layers with an angle of 60° two outer-layers of scintillating fibres: x-y determination due to the crossing of the fiber-layers with an angle of 60° additional fast timing information for charged particles – background suppression for inner tracking detector (TPC+GEM) AMADEUS setup- second version (in collaboration with KLOE - for vertex detector)

full toroidal cryogenic target cell vacuum chamber thin-walled beam pipe 2 outer-layer of scintillating fiber fiber size: 1x1mm 2 kaon trigger: 2 inner-layer of scintillating fiber fiber size: 1x1mm 2 AMADEUS setup with full toroidal cryogenic target cell

Cryogenic toroidal target cell: working temperature: K working pressure: < 2 bar thin-walled design: 75µm Kapton, with aluminum grid reinforcement (grid transmission > 85 %) inner diameter: 110 mm outer diameter: 210 mm inner length: 120 mm outer length: 200 mm

production rate for charged kaon pairs R = L  b = 1500 s -1 peak luminosity 3 × cm 2  production cross section cm -2 s -1 produced K ± per month: 31 × 10 8 (80% duty cycle assumed) 40% are stopped in the cryogenic He gas target (15% liq. He density, ~ 5 cm thick)  12.5 × 10 8 K - 4 He atoms per month for cluster formation yield: 12.5 × 10 5 kaonic clusters formed in one month  Efficiency of tracking & identification K ± & detection of decay products  ~ 10 5 events per month (~ 1000 pb -1 ) 0.49 branching ratio for K ± Results of preliminary MonteCarlo simulations for AMADEUS setup with optimized degrader and cryotarget

Event Display for ppnK - Decay ppnK -   0 + n + p       p Interaction region Cryogenic target cell TPC-GEM Segmented degrader Kaon trigger K - stopped p  n  p -- --  KLOE-DC KLOE-EMC

7. Data analysis of 2 fb -1 KLOE existing data

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

Preliminary Monte Carlo simulations shows that with 2 fb -1 one might have and type events K He -> n + (K - ppn) n ~ 510 MeV/c K He -> p + (K - pnn) p ~ 550 MeV/c Pre-experiment: Proposal to KLOE 31th LNF Scientific Committee CC,JZ / Nov. 29, 2005

Signature for ppnK - Decay decay:  ° + p + n p +  - 4 He + K -  ppnK - + n n n p p -- --

(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 AMADEUS MonteCarlo: to get the K - stopped in Helium of DC ~ 0.3% stopped in the gas of the chamber

~ 0.3% K - stopped in the gas of the chamber  3 × × 3 × 10 9 = 9 × 10 6 (K - 4 He) atoms For a cluster yield of ~10 -3 ~ 10 4 kaonic clusters One should take into account: Efficiency of tracking & identification K ± & detection of p, n and of the decay products AMADEUS preliminary estimate:

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 First results What happened in the last months:

Actions: - Start dedicated MonteCarlo Ntuple production - 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.) - First results Start MC analysis:

Charged Kaon Monte Carlo As an exercise: study K + stop Signal side: K +

K + → μ + ν PμPμ PνPν

0.2% stopped inside the DC's 0.05% stopped in the beam pipe (Berillium) ρ vs. Z (cm) K + → μ + ν 0.5% stopped inside the DC-wall (Carbon) 1.3% stopped

Signal side: K -

Nuclear Interactions: K - + N 1.2% of K - undergoing Nuclear interaction K-K- K+K+

K - “stopped” (with quality cuts) Nuclear Interactions: K - + N ρ vs. Z (at last DC measurement) 0.2% stopped inside the DC's | z | < 140 cm 26 < ρ < 180 cm

K - “stopped” (quality cuts) Nuclear Interactions: K - + N ρ vs. Z (at last DC measurement) 0.1% stopped inside the DC's | z | < 140 cm 40 < ρ < 150 cm

~ % K - stopped in the gas of the chamber  1-2 × × 3 × 10 9 = 3-6 × 10 6 (K - 4 He) atoms For a cluster yield of ~10 -3 ~ x 10 3 kaonic clusters Next step: Evaluate the various efficiencies: tracking & identification K ± & detection of p, n and of the decay products Preliminary results (updated): Preliminary results (updated):

-Finalize the MCarlo analyses by evaluating the various efficiencies in formation/decay processes (numbers of expected reconstructed events) -Start preliminary analysis of the final data (on a small data set) in order to understand background and to tune the strategy of the overall data analysis -Start massive real data analyses under the supervision of KLOE team, as soon as data will be available for analyses -Investigate possibility to look for low energy kaon+/- interactions Future plans:

7. Conclusions

Letter of Intent Study of deeply bound kaonic nuclear states at DA  NE2 AMADEUS Collaboration March scientists from 33 Institutes of 13 Countries signed the Letter of Intent Confirmed their interest/participation

Further requests (other targets) depend on the results of these first measurements The AMADEUS enriched program (KN and K-Nuclei Physics) can be done partially in parallel with previous one Some measurements (scattering) might need dedicated beam-time From AMADEUS LOI: Possibly at DAFNE with Luminosity upgrade (before J-PARC, FOPI, FAIR)

Conclusions (1) 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. 2.AMADEUS can perform fundamental measurements in the sector of kaon-nucleon and kaon-nuclei physics -> enriched program

Conclusions (2) 2.To realize 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 efficient neutron detector was fully proved by the determination of the high neutron detection efficiency -> KLONE. 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.