friday, december 10, 2010

Friday, December 10, 2010

Oton Vázquez DoceLNF - INFN

Studies of antikaon interactions with nucleons at DAΦNE

K‐N interactions @ DAΦNE Oton Vázquez Doce

DAΦNE AMADEUS KLOE data analysis

17 km

Colosseo 70–80 AD Ø 545 m

DAΦNE 2008 AD (upgrade) Ø 200 m

The DAΦNE e+e- collider

• e+ e- beams at ~ 500 MeV/c•Φ → K+ K- (49.1%)•Monochromatic low-energy K- (~127 MeV/c)•Low hadronic background due to beam characteristics (compared with hadron beam lines, as KEK)


DAΦNE upgrade in 2008 Design of new interaction region scheme

Top luminosity reached during SIDDHARTA run:4x1032 pb-1 s-1



Experimental timeline at DAΦNE

DEAR kaonic hydrogen

FINUDA hypernuclei

KLOE CP violation

SIDDHARTA kaonic atoms

KLOE2

AMADEUS* kaonic nuclei

past

present

proposal for the future

(KLOE2+) SIDDHARTA2*



next talk in this session by S. Okada

How deep is the KN potential?

KLOE DC The AMADEUS experiment

• Search for the kaonic nuclear clusters• Characterize the hadronic interactions and

scattering of K- in light nuclei• doing it by implementing new devices in the inner

region of the KLOE detector for studying the (most) fundamental antikaon bound nuclear systems



A hadron physics important and unresolved topic: How the hadronic masses and interaction change in nuclear medium


DAΦNE AMADEUS: kaonic clusters KLOE data analysis


Y. Akaishi and T. Yamazaki (Phys. Rev. C65 (2002) 044005)

Strong attractive I=0 KN interaction favors discrete nuclear states high B and small Γ .

Discussion triggered by the prediction of the Deeply bound kaonic nuclear states




Y. Akaishi and T. Yamazaki (Phys. Rev. C65 (2002) 044005)

Strong attractive I=0 KN interaction favors discrete nuclear states high B and small Γ .

Discussion triggered by the prediction of the Deeply bound kaonic nuclear states

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

From experimental data:• S-wave K- nucleon scattering length is negative at threshold

“repulsive type” interaction

KN potential strongly dependent on density: → repulsive in free space → attractive in nuclear matter

• K line shift of kaonic hydrogen is negative




A strong attractive potential will allow the formation of deeply bound kaonic clusters, with exotic features that would allow to investigate:

- spontaneous and explicit symmetry breaking of QCD- kaon condensation in nuclear matter (neutron stars)- super dense matter (x5 normal nuclear matter)

etc

Studying the properties of the KN potential in the nuclear medium





etc



Intense theoretical debate with several different approaches:- Few-body calculations solving Faddeev equations - Variational calculations with phenomenological KN potential- KN effective interactions based on Chiral SU(3) dynamics




etc



Intense theoretical debate with several different approaches:- Few-body calculations solving Faddeev equations - Variational calculations with phenomenological KN potential- KN effective interactions based on Chiral SU(3) dynamics

For K-pp system, predicted values both for B and Γexpand over the range from 0 to 200 MeV

KK

ΛpExperimental results from FINUDA

ΛdK- stopped in light nucleiInvariant mass spectroscopy

kaonic 3-baryon state: ppnK-

kaonic dibaryon state: ppK-

Experimental data



KK


ΛdK- stopped in light nucleiInvariant mass spectroscopy Λd

Results from KEK:Λp

Λd

K- stopped in 4HeInvariant mass spectroscopy



Experimental data



KK




Λd


p¯ 4He annihilationDISTO Λp OBELIX Λp

p+p → K++X p4He annihilation (Λd)



Experimental data


DAΦNE AMADEUS: kaonic clusters KLOE analysis

KK




Λd


p¯ 4He annihilationDISTO Λp OBELIX Λp

p+p → K++X p4He annihilation (Λd)



Experimental data

KK

ΛpExperimental results from FOPI

Λdfrom HEAVY ION COLLISIONS


DAΦNE AMADEUS: kaonic clusters KLOE analysis

Nucl.Phys.A835:51-58,2010. arXiv:1001.1300



Nucl.Phys.A835:51-58,2010. arXiv:1001.1300

the future experiments in Japan at J-PARC will produce kaonic nuclear states only with K--induced reactions in- flight (E15; E17)

alternative approaches followed at GSI with FOPI using proton-nucleus collisions at beam energies close to the strangeness production threshold and with nucleus- nucleus collisions

a dedicated facility – AMADEUS at DANE will study antikaon-mediated bound nuclear systems with K- induced reactions at rest



AMADEUS: The main program

kaonic 3-baryon states: ppnK- and pnnK-

produced in a 4He gas target

kaonic dibaryon states: ppK- and pnK-

produced in a 3He gas targetStudy the most fundamental antikaon deeply bound systems in formation and decay processes:


DAΦNE AMADEUS: experimental program KLOE data analysis

AMADEUS: extended program

Low-energy charged kaon cross section on p, d, He-3 and He-4, for K- momentum lower than 100 MeV/c (missing today)

The K- nuclear interactions in Helium (poorly known – based on one paper from 1970…)

Properties of Λ and charged Σ´s for example decays in channels with a neutrino → astrophysics implications (cooling of compact stars)

Resonance states as Λ(1405) or the Σ(1385) could be understood with high statistics; their behaviour in nuclear medium can be studied too



AMADEUS: three key features

Full acceptancy

Full reconstruction

Invariant mass +Missing mass

Pureness



From KLOE to AMADEUS Full acceptance and high precision measurements will be made by implementing the KLOE detector with an inner AMADEUS setup(50 cm. gap in KLOE DC around the beam pipe)


DAΦNE AMADEUS setup KLOE data analysis

DRIFT CHAMBER

ELECTROMANETIC CALORIMETER

Almost full acceptancy 4π:

From KLOE to AMADEUS

Setup for AMADEUSwithin KLOE:

Full acceptance and high precision measurements will be made by implementing the KLOE detector with an inner AMADEUS setup(50 cm. gap in KLOE DC around the beam pipe)

K-stopped + 4He → n + (K-ppn)

K-stopped + 4He → p + (K-pnn)

• Modification of the beam pipe of KLOE-2 in order to allow access

• Target ( A gaseous He target for a first phase of study)

• Trigger (1 or 2 layers of ScFi surrounding the interaction point)

• Inner tracker (eventually, a first tracking stage before the DC)

The implementation of the AMADEUS dedicated setup around the beam pipe will modify the topology of the events, stopping the K- in a target inner to the DC.



KLOE2

AMADEUS

Central region made of CARBON FIBER:- Vacuum chamber- External part of cryostate and target walls

Aluminium for the peripheral part

AMADEUS setup: beam pipe



Low-mass cryogenic gas target cell:T = 10 KP = 1.0 barRin = 5 cmRout = 15 cmL = 20 cm

working T 22 K working P 1.5 bar Alu-gridSide wall: Kapton 50 µmEntrance window: Kapton 50 µm

SIDDHARTA

AMADEUS:

AMADEUS setup: target cell



Low-mass cryogenic gas target cell:T = 10 KP = 1.0 barRin = 5 cmRout = 15 cmL = 20 cm

working T 22 K working P 1.5 bar Alu-gridSide wall: Kapton 50 µmEntrance window: Kapton 50 µm

AMADEUS:

AMADEUS setup: target cellAMADEUS Monte Carlo

SIDDHARTA Monte Carlo



SIDDHARTA

AMADEUS setup: Trigger system



AMADEUS setup: Trigger system

Ideal for ScFi couplin and high granularity detectorTime resolution below 1 nsInsensitive to strong magnetic fieldsHigh gain (>106) and quantum efficiency

MPPC Hamamatsu S10362-11-050U, efective area 1mm2,,400 pixel wlorking biases ̴ 70 V .

Instrumented fibers: Saint Gobain BCF- 10 single cladding:

- Emission peak 432 nm- Decay time 2,7 ns- 1/e 2.2 m- 80000 ph./MeV

Silicon photomultipliers + scintilliating fibers



Laser directly on SiPM; 1 KhzRes ≈ 40 ps

Amplifier is not worsening!

Laser directly on fiber:Resolution is slightly worse ≈ 80 ps due to internal reflexion

TIME RESOLUTION STUDY@ Roma3 University

SiPM + Pre-amp + scintilliating fiber



tests installation at DAΦNE

SIDDHARTA setup

DAΦNE beam pipe

Our test setup

Siddharta Kaon Monitor2Layers of Scintillators up&downThe interaction point detecting K+ K- emmited in opposite directions



AMADEUS setup: Trigger systemNew TEST SETUP

Test beam at BTF in Frascati and past at PSI (Zurich) wiht hadrons

2-rings of double layer 16 fibres

64 fast pre-amplifiers (64x)

2 boards of 32 constant fraction discriminator with zero jitter



AMADEUS setup: Trigger systemNew TEST SETUP

Test beam at BTF in Frascati and past at PSI (Zurich) wiht hadrons

2-rings of double layer 16 fibres

64 fast pre-amplifiers (64x)

2 boards of 32 constant fraction discriminator with zero jitter

Pion an electron fluxes in piM1



Experimental timeline at DAΦNE

DEAR kaonic hydrogen

FINUDA hypernuclei

KLOE CP violation

SIDDHARTA kanonic atoms

KLOE2

AMADEUS* kaonic nuclei

past

present

proposal for the future

(KLOE2+) SIDDHARTA2*



The KLOE detector

KLOE@ DAΦNE

DRIFT CHAMBER- 90% He- momentum resolution ~ 0.4%

ELECTROMANETIC CALORIMETER- σE/E= 5.7%/√E (GeV)

Almost full acceptancy 4π:


for CPT symmetry and QM tests, hadronic physics, and more

by S. Miscetti @ QuarkConfinement IX. Madrid, 2010

Status of KLOE2. arXiv:1001.3591, G. Venanzoni for the KLOE2 collaboration


KLOE data analysys:

EMC

Drift Chamber

The implementation of the AMADEUS dedicated setup will modify the topology of the events, stopping the K- in a target inner to the DC.

K-

K+

4He

how K+/K- events looks like nowadays in KLOE:

e+

e-

•The Drift Chamber of KLOE contains mailny 4He (90%, 10% isobutane)

•From analysis of KLOE data and Monte Carlo: 0.1 % of K- shouldstop in the DC volume

•This would lead to hundredsof events with K- hadronic interactions at rest

“AMADEUS Step-0”

- Test the behaviour of the KLOE detectorfor hadronic physics purposes- Possibility to study the phenomenon with an active target


DAΦNE SIDDHARTA AMADEUS KLOE data analysis

Λ + pK-

stopped + 4He → n + n + (K-pp)

Λ + dK-

stopped + 4He → n + (K-ppn)

•Statistics: analyzing data up to an integrated luminosity of ~1,7 fb-1 (80% KLOE RUNS 2004/2005)•Data analysis: search for hadronic interactions with Λ(1115):

• Λ → p + π- (64% BR)• Construct a vertex with Λ + an extra particle



Λ + pK-

stopped + 4He → n + n + (K-pp)

Λ + dK-

stopped + 4He → n + (K-ppn)

•Statistics: analyzing data up to an integrated luminosity of ~1,7 fb-1 (80% KLOE RUNS 2004/2005)•Data analysis: search for hadronic interactions with Λ(1115):

• Λ → p + π- (64% BR)• Construct a vertex with Λ + an extra particle


deuterons

protons

•Protons and deuterons are firstly selected from the spectrum of particles near to the Lambda vertex by dE/dx

EMC

charge * p(MeV/c)

dE/d

x (a

dc co

unts

)protons

deuteronsDC

charge * p(MeV/c)

E (M

eV/c

)

PID


protonpion

kaonother

DC volumeEcal

x (cm)

y (c

m) Λ + p

Λ + d

2 different vertices reconstrucion:Λ -> p + pion(K- + 4He) -> Λ + d

Proton from Λ Are required to have at least 1 clusterDeuteron /proton to reproduce the time of the event

- Calculate p/d mass by TOF-Evaluate Σ0 background-Use Λ lifetime as quality cut

Kaon is rarely tracked due to its low momentum or short trackCluster in the ECAL

(time info)

Selection of events



Selection of events



• Proton/deuteron candidates are required to have an associated cluster in the EMC and its mass is measured by time of flight.

Mdeuteron (MeV/c2) Time (ns)

1/3.7 -> τ=0.25 ns (PDG=0.26)

LAMBDA LIFETIME



Improved Λd vertex reconstruction

Vertex radial position (cm)

Λ -> p+πΛ+d

Improved selection of events in DC-gasΛd vertex

Λ vertex

Selection of events



• Proton/deuteron candidates are required to have an associated cluster in the EMC and its mass is measured by time of flight.

Mdeuteron (MeV/c2) Time (ns)

1/3.7 -> τ=0.25 ns (PDG=0.26)

LAMBDA LIFETIME



KLOE: statistical error 0. 003 MeV/c2

PDG: MΛ = 1115,683 ± 0.006 stat ± 0.006 syst (MeV/c2)

Λ → p + π-

Invariant masses Preliminary

Minv pπ (MeV/c2)


σ = 0. 289 ± 0.003 MeV/c2


KLOE: statistical error 0.003 MeV/c2

PDG: MΛ = 1115,683 ± 0.006 stat ± 0.006 syst (MeV/c2)

σ = 0. 289 ± 0.003 MeV/c2

Λ → p + π-

Invariant masses Preliminary

Minv pπ (MeV/c2)

Minv Λd (MeV/c2)

Total events in DC Volume 79

Md+ Mp+ Mπ- Md + Mp+ MK

Λd analysis

PΛ (MeV/c)

Pd (MeV/c)

Efficency for tracks with P < 400 MeV improved increased acceptancy



Λ + d

K-stopped + 4He → n + (K-ppn)Λd analysis

Neutral particles detection



Λ + d

K-stopped + 4He → n + (K-ppn)Λd analysis




Λ -> n π0

proton

π

p

Λ

Ecal

Σ0

Use of the time information from the EMC

-With the extrapolation of the charged andneutral (lambda) tracks the time of theInteraction (Tk) is obtained

Time correlation between neutral clusters(not associated to any charged track) and Tkassuming a photon travelling:

Tphoton -Tk (MeV/c)

Tk

Minv γγ (MeV/c2)

Σ0 contamination in Λp events




...on the nature of the Λ(1405)

γ Ecal

π

p

Λ

γ

Ecal

γΣ0

π0

• 3-quark baryon?• KN quasibound state?• two pole KN-Σπ channel coupling?

(Σπ)0 spectrum

D. Jido, E. Oset and T. Sekihara,``Kaonic production of Lambda(1405) off deuteron target in chiral dynamics''

arXiv:0904.3410 [nucl-th].



possible task for AMADEUS?


γ Ecal

π

p

Λ

γ

Ecal

γΣ0

π0


(Σπ)0 spectrum

pseudo-kinematic fit:•χ2 computing:

-momentum of proton and pion-Covariance matrix elements for every track-time and positions plus resolutions for photons

•Allows to reject background selecting the right combination of photons•Constraints: Δt for the arrival time of photons•No mass assumption -> unbiased mass spectras




γ Ecal

π

p

Λ

γ

Ecal

γΣ0

π0


(Σπ)0 spectrum

Kinematic fit:•χ2 computing:

-momentum of proton and pion-Covariance matrix elements for every track-time and positions plus resolutions for photons

•Allows to reject background selecting the right combination of photons•Constraints: Δt for the arrival time of photons•No mass assumption -> unbiased mass spectras

Minv Λγ (MeV/c2)

Min

v γγ

(MeV

/c2 )

Minv γγ (MeV/c2) Minv Λγ (MeV/c2)



(Σπ)0 spectrum

MinvΣ0π0 (MeV/c2)

Events in theDC volume

DC wall

Preliminary




K- He interactions in KLOEPROVED

• Capabilities of the KLOE detector for studying K- hadronic interactions

• Possibility to study the phenomenon with an active target

TO DO LIST• Apply acceptance correction for invariant masses distributions

• Evaluate background distributions (hadronic interaction, multi-nucleon absorption, etc) for the analises shown previously (Monte Carlo)

• Exploit the neutral particles detection capabilities of KLOE (Kppn -> Λ d n, neutral decay of Λ , etc)

• Determine rates for the different reactions in 4He and in 12C

• Exotic (and not so) physics data:) hypernuclei, Σ(1385), etc.

• New KLOE data!




CONCLUSIONS

DAΦNE AMADEUS conclusions KLOE data analysis

DAΦNE AMADEUS conclusions KLOE data analysis



CONCLUSIONSMinutes from last LNF Scientific Committee

THANK-S

AMADEUS setup: TPG for inner tracking

Prototype tested last week at BTF


DAΦNE SIDDHARTA AMADEUS: experimental setup KLOE

Λ p analysisInvariant mass

Minv Λp (MeV/c2)

Total events in DC Volume 187

2Mp+Mπ- 2Mp+MK

PΛ (MeV/c)

P p (M

eV/c

)

Minv Λp (MeV/c2)

Pp (MeV/c)

NO EMC-CLUSTER (mass by TOF)requirement for protons !!!!

Rely only on DEDX in the DC wires -->

charge * p(MeV/c)

dE/dx (adc counts)

protons

Preliminary

dE/d

x (a

dc co

unts

)deuterons

triton

protons

Selection of triton PID

K‐He interactions in KLOE Oton Vázquez Doce

Mass by time of flight (MeV/c2)

triton

Cos θ (Λt)MΛ(MeV/c2)

PΛ (MeV/c)

Mt (MeV/c2)

Pt (MeV/c)

Lambda-triton


triton

Cos θ (Λt)MΛ(MeV/c2)

PΛ (MeV/c)

Mt (MeV/c2)

Pt (MeV/c)

Minv Λt (MeV/c2)

ρ < 40 cmDC inner wall

ρ > 40cmDC volume

Lambda-triton


friday, december 10, 2010

Documents

nuclear medium dane

nuclear medium kn interactions

bound kaonic clusters

kloe dckn interactions

negative kn interactions

kekkn interactions

dane1kn interactions

experimental data