AMADEUS

C. Guaraldo - 32nd Meeting of LNF Scientific Committee, 31st May -1st June 2006

AMADEUSAMADEUS

32nd Meeting of the LNF Scientific Committee31st May – 1st June 2006

C. Guaraldo

AAntikaon MMatter AAt DDANE:

EExperiments with UUnravelingnraveling SSpectroscopy


ContentsContents

1. Introduction

2. The case of AMADEUS

3. The framework of the AMADEUS Proposal

4. Realizing AMADEUS

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

6. Implementation of the AMADEUS setup within KLOE

7. Analysis of the Helium data of the KLOE Drift Chamber

8. Conclusions


1. Introduction1. Introduction


Letter of Intent

Study of deeply bound kaonic nuclear states

at DANE2

AMADEUS Collaboration

March 2006


111 scientists from 33 Institutes of 13 Countries signed the Letter of Intent


2. The case of AMADEUS2. The case of AMADEUS

The case of AMADEUSThe case of 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 changes in the nuclear medium

Deeply bound pionic atomsDeeply bound pionic atoms

Successful example of deeply bound mesonic states

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.

Subtle balance at the surface of a heavy nucleus between the Coulomb attraction and the repulsion resulting from the pion-nuclear strong interaction.

Deeply bound states in pionic atoms

T. Yamazaki, P. Kienle et al., Z. Phys. A355 (1996) 219

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

Deeply bound kaonic nuclear statesDeeply 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 I=0 KN interaction favors discrete nuclear states bound100-200 MeV and narrow 20-30 MeV

shrinkage effect of a K on core nuclei


The KN interactionThe KN interaction

Deeply bound kaonic nuclear states require the presence of a strong attractive KN interaction in the isospin I=0 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

Cou

nts

/ 60

eV

X-ray energy (keV)

KK

K

wid

th

1s

[eV

]

-500 50000

200

400

600

800

1000

shift 1s [eV]

Dav

ies

et a

l, 19

79

Izyc

ki e

t al,

1980

Bir

d et

al,

1983

repulsive attractiveKpX (KEK)M. Iwasaki et al, 1997

DEAR

SIDDHARTA

=

- 3

23 ±

63

± 11

eV

=

407

± 2

08 ±

100

eV

Results on the shift and width for kaonic hydrogenResults on the shift and width for kaonic hydrogen

DEAR results:G. Beer et al., Phys.Rev.Lett. 94, (2005) 2123021s = - 193 ± 37(stat) ± 6(syst) eV1s = 249 ± 111(stat) ± 30(syst) eV

klkX-ray energy (keV)


In-medium effects on the dynamics of the In-medium effects on the dynamics of the (1405) (1405)

If the s-wave, isospin I=0 (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


In-medium effects on the dynamics of the In-medium effects on the dynamics of the (1405) (1405)

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

influence of the nuclear medium on (1405) formation

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 = (3π2 ρ/2)1/3, as a function of the total c.m.

energy √s .

a) free space, pF = 0; b) ~ 0.2 ρ0, pF = 150 MeV/c; c) ~ 1.4 ρ0, pF = 300 MeV/c; ρ0 = 0.17 fm-3

Influence of the nuclear medium (Pauli blocking) Influence of the nuclear medium (Pauli blocking) on the formation of the on the formation of the ΛΛ(1405)(1405)

K- p threshold

In free space, at threshold, point A, aK-p<0 repulsive interaction

In nuclear matter at rather low density (0.2 0), at threshold, point B, aK

-p>0

attractive interaction

1432

B

A

T. Waas, N. Kaiser, W. Weise, Phys. Lett. B 365 (1996) 12

Role of a bound state below thresholdRole 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 I=0 channel and the proton-neutron (p-n) scattering in the deuteron channel (I=0, S=1):

the interaction between the proton and neutron is attractive, but the scattering length in the deuteron channel (I=0, S=1) 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.


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

The framework of the AMADEUS ProposalThe framework of the AMADEUS Proposal

Experiments

Present: KEK E471, E549, E570 DANE 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?


AMADEUS philosophy/ strategyAMADEUS 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


4. Realizing AMADEUS4. Realizing AMADEUS


Realizing AMADEUSRealizing 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 5. Determination of the neutron detection efficiency of neutron detection efficiency of

the KLOE e.m. calorimeterthe KLOE e.m. calorimeter


K- + 4He (ppnK-) + n

The (pnnK-) kaonic cluster may decay through the following channels:

(ppnK-) + d + np + pp + d

+ np with the and ’s decaying according to PDG.

Strange tribaryon formation


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 energiesRange of interest of neutron energies


MonteCarlo simulations

AMADEUS MonteCarlo GEANT simulation (and FLUKA

MonteCarlo from KLOE)

Measurement with a neutron beamKLOE+AMADEUS experimental test of a prototype of the

KLOE calorimeter on the neutron beam of TSL (Uppsala):

KLONE proposal

Determination of the KLOE calorimeter Determination of the KLOE calorimeter efficiency for neutronsefficiency for neutrons


AMADEUS Technical Note IR-1, 4 March 2006

M. Cargnelli

STEFAN MEYER Institute for Subatomic Physics, Vienna, Austria

C. Curceanu

Laboratori Nazionali di Frascati dell’INFN, Frascati, Italy

A prelimnary GEANT MonteCarlo simulation A prelimnary GEANT MonteCarlo simulation of the KLOE calorimeter: extraction of the of the KLOE calorimeter: extraction of the

efficiency for neutron detectionefficiency for neutron detection


KLOE calorimeterKLOE calorimeter


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.

The calorimeter MC modelThe calorimeter MC model

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.

GEANT 3.21 simulation - inputsGEANT 3.21 simulation - inputs

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.

The ratio of the number of neutrons depositing energy versus thetotal number of incoming neutrons gives the intrinsic efficiency.

GEANT 3.21 simulationexample of events

GEANT 3.21 simulation – example of events


Threshold at 1 MeVThreshold at 3 MeV

MonteCarlo simulation - Calorimeter responseMonteCarlo simulation - Calorimeter response

Neutron detection efficiency


Results in agreement with FLUKA dedicated simulations performed by KLOE.

Refined MonteCarlo simulations to understand details (topology, etc.) are undergoing.


Test of a calorimeter prototype on a neutron beam:

KLOE + AMADEUS, mixed team of ~ 15 persons, lead by Stefano Miscetti

Measurement of the neutron efficiency Measurement of the neutron efficiency using a test beam using a test beam


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

The KLONE proposal at TSL (Uppsala)The KLONE proposal at TSL (Uppsala)


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


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.

The TSL neutron beam at Uppsala (1)The TSL neutron beam at Uppsala (1)


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.

The TSL neutron beam at Uppsala (2)The TSL neutron beam at Uppsala (2)

KLONE setup

Blue Hall at TSL and neutron beam Blue Hall at TSL and neutron beam


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

Performed actions Performed actions


KLONE Project at TSL - approved on 18/05/2006 code F183 assigned

- beam time allocated in October 2006:week 42 and 43in Frequency Modulation (FM) mode (100-180 MeV energy range)


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

Future working plan Future working plan


6. Implementation of the 6. Implementation of the AMADEUS setup within AMADEUS setup within

KLOEKLOE


KLOE – EMC

KLOE –Drift Chamber

Possible setupfor AMADEUSwithin KLOE:

Cryogenic targetInner trackerKaon trigger

AMADEUS setup within KLOEAMADEUS setup within KLOE


There are presently 2 versions:

- without a vertex/inner tracking detector (minimal version)

- with a vertex/inner tracker detector

AMADEUS setupAMADEUS 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 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

The kaon triggerThe kaon trigger


half-toroidal cryogenic target cell

1st inner-layer ofscintillating fibrefiber size: 1x1mm2

2nd inner-layer ofscintillating fibrefiber size: 1x1mm2

three outer-layersof scintillating fibrefiber size: 1x1mm2

AMADEUS setup-minimal versionAMADEUS setup-minimal version(with the collaboration of Vincenzo (with the collaboration of Vincenzo Patera)Patera)


We need the position of the K- stop = primary vertex

Then the kaon tracker might be essential (under study)

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

Technical solutions (type of detector) and plans for prototyping and testing are being discussed and under evaluation

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



two TPC sectionswith triple GEM and x-y readout on both sides

kaon trigger made of2+3 scintillating fibers layers,inside a vacuum chamber

half-toroidal cryogenictarget cell

vacuum chamber

thin-walledbeam pipe

AMADEUS setupAMADEUS setupsecond versionsecond 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 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 (TPC+GEM)



full toroidalcryogenictarget cell

vacuum chamber

thin-walledbeam pipe

2 outer-layer ofscintillating fibrefiber size: 1x1mm2

kaon trigger:2 inner-layer ofscintillating fibrefiber size: 1x1mm2

AMADEUS setup with full toroidal AMADEUS setup with full toroidal cryogenic target cellcryogenic target cell


Cryogenic toroidal target cell:

working temperature: 5 -10 Kworking 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 pairsR = L b = 1500 s-1

peak

lum

inos

ity

3 ×

10-3

0 cm

2

p

rodu

ctio

n cr

oss

sect

ion

10

33 c

m-2 s

-1

produced K± per month: 31 × 108 (80% duty cycle assumed)

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)

0.49

bra

nchi

ng ra

tio fo

r K±

Results of preliminary MonteCarlo simulations for Results of preliminary MonteCarlo simulations for AMADEUS setup with optimized degrader and cryotargetAMADEUS setup with optimized degrader and cryotarget


7. Data analysis of 2 fb7. Data analysis of 2 fb-1 -1

KLOE dataKLOE data


Data analysis of the 2 fb-1 KLOE datato search for kaonic nuclear clusters

produced in the reaction 4He(K-

stopped, nucleon)

E471 KEK results4He(K-

stopped, p) and 4He(K-

stopped, n) missing mass spectra

M. Iwasaki et al., nucl-ex/0310018 v2

Preliminary Monte Carlo simulations shows that with 2 fb-1 one might have> 1500 K- stopped events in Helium of KLOE Drift Chamber, of the type:

and > 500 events of the type

AMADEUS group willing to help KLOE in data analysis

K- + 4He -> n + (K-ppn) n ~ 510 MeV/c (assuming n~ 30%)

K- + 4He -> p + (K-pnn) p ~ 550 MeV/c

Pre-experiment: Proposal to KLOE Pre-experiment: Proposal to KLOE

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


1) Refined MCarlo simulations with the AMADEUS code

2) AMADEUS officially accepted in the Kcharged group of

KLOE

3) Mixed team KLOE-AMADEUS got formed and started to

work

4) Training of AMADEUS team by the KLOE Kcharged team

5) KLOE MCarlo dedicated production and start analysis

6) Plan for data analysis

What happened in the last months: What happened in the last months:

Schematicside view ofthe KLOE detector

e+ e-

K+

The drift chamber isfilled with He + isobutaneat atmosphericpressure;He as active volume

K-

p

K-pnn

KLOE detectorKLOE detector


K- 4He

ppnK n pnnK p

d n p p p d n p n n n p d n n

n n p

Measure 1 particle of a 2-body decay.Transform to cms of the decayingObject. Gives 2nd particle properties.Missing mass spectroscopy

Measure all outgoing particles to obtain thetotal cms energy = invariant mass of the object

Reaction channels (simplified)Reaction channels (simplified)


Monte Carlo simulation: 100000 events

P() GeV/c

K- + 4He n + (K-ppn)

npP(p) GeV/c

P() GeV/c

P(p) GeV/cP(n) GeV/c


(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 KAMADEUS MonteCarlo: to get the K-- stopped stopped in Helium of DCin Helium of DC

KLOE Drift chamberE

ven

ts /

bin

z-position (mm) radial-position (mm)

K± entering chamber

K- stopped in the chamber

K- stopped in the chamber

z = beam direction collision zone: z = 30 mm

~ 0.3% stopped in the gas of the chamber

K- stopped in HeliumK- stopped in Helium


Kaon production rate: ~ 150 K- s-1 (for L ~1032 cm-2 s-1 )

N = L b = 2.9 × 109

2 fb

-1 = 2

× 1

039 c

m-2

i

nteg

rate

d lu

min

osity

0.49

bra

nchi

ng ra

tio fo

r K±

Total number of produced charged kaon pairs for L = 2 fb-1

~ 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

3 ×

10-3

0 cm

2

p

rodu

ctio

n cr

oss

sect

ion

AMADEUS MonteCarlo:AMADEUS MonteCarlo:K-clusters in existing KLOE dataK-clusters in existing KLOE data


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)

AMADEUS officially accepted in the K charged AMADEUS officially accepted in the K charged team of KLOEteam of KLOE


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.

Start working on analysis (1):Start working on analysis (1):


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.)

Start working on analysis (2):Start working on analysis (2):


~ 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

Preliminary results:Preliminary results:


- 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

Future plans:Future plans:


7. Conclusions7. Conclusions


Conclusions (1)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.

The goal is to definitely clarify their debated existence.


Conclusions (2)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.

AMADEUS

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