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A search for deeply-bound kaonic nuclear states by in-flight 3 He(K - ,n) reaction at J-PARC. J-PARC E15 experiment. S. Ajimura, G. Beer, H. Bhang, P. Buehler, L. Busso, M. Cargnelli, J. Chiba, S. Choi, C. Curceanu, D. Faso, H. Fujioka, T. Fukuda, Y. Fukuda, C. Guaraldo, - PowerPoint PPT Presentation
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A search for deeply-bound kaonic nucA search for deeply-bound kaonic nuclear states lear states
by in-flight by in-flight 33He(KHe(K--,n) reaction ,n) reaction at J-PARC at J-PARC
Hiroaki OhnishiHiroaki OhnishiRIKEN Nishina CenterRIKEN Nishina Center
J-PARC E15 experimentS. Ajimura, G. Beer, H. Bhang, P. Buehler, L. Busso, M. Cargnelli, J. Chiba,
S. Choi, C. Curceanu, D. Faso, H. Fujioka, T. Fukuda, Y. Fukuda, C. Guaraldo, T. Hanaki, R. S. Hayano, A. Hirtl, M. Iio, M. Iliescu, T. Ishikawa, S. Ishimoto,
T. Ishiwatari, K. Itahashi, M. Iwasaki, P. Kienle, J. Marton, Y. Matsuda, Y. Mizoi, O. Morra, T. Nagae, H. Ohnishi, S. Okada, H. Outa, A. Sakaguchi, M. Sato, M. Sekimoto, D. Sirghi, F. Sirghi, S. Suzuki, T. Suzuki, H. Tatsuno, D. Tomono, A. Toyoda, E. Widmann, T. Yamazaki, H. Yim, and J. Zmeskal
Search for Kaonic nuclear bound stateSearch for Kaonic nuclear bound stateExperiment Reaction Target Experimental method
KEK E471/ E549 stopped K- 4He missing mass
FINUDA stopped K- 6Li,7Li,12C invariant mass
BNL E930, KEK E548 in- flight K- 16O,12C missing mass
GSI FOPI invariant massOBELIX anti- p 4He invariant mass
Heavy ion collision
Phys. R
ev. Lett. 94
212303 (2005)
Taken from
OH
P at T
rento WS
2006
KEK E549 FINUDA
KEK E548
Taken from
OH
P at T
rento WS
2006
GSI FOPI
What we need to answer the basic question, What we need to answer the basic question, whether the deeply bound state really exists?whether the deeply bound state really exists?
The situation is still controversial!
OBELIX
Experiment Reaction Target Experimental methodKEK E471/ E549 stopped K- 4He missing & invariant mass
FINUDA stopped K- 6Li,7Li,12C invariant mass
BNL E930, KEK E548 in- flight K- 16O,12C missing mass
GSI FOPI invariant massOBELIX anti- p 4He invariant mass
Heavy ion collision
Results of in
variant m
ass analysis
from E549 will
be presented
in INPC2007 conference
by Dr. T. S
uzuki
What we want to What we want to do ?do ? Back to the original questionBack to the original question
Structure inside Structure inside (1405)(1405) multiquarks state?multiquarks state? Double pole resonance ? Double pole resonance ? bound state of Kbound state of K--p ?p ?
Existence of K-pp bund stateWill open new door to
the physics of K-cluster
If we assume If we assume (1405) to be a K(1405) to be a K--p bound statep bound state Second simplest bound state, KSecond simplest bound state, K--pp, will also existpp, will also exist
( natural extension) ( natural extension)
A search for deeply bound A search for deeply bound kaonic nuclear stateskaonic nuclear states
Direct production of K-pp clusters Direct production of K-pp clusters via via 33He(in-flight KHe(in-flight K--,n) reaction,n) reaction
Goal for the experiment J-PARC E15Goal for the experiment J-PARC E15 To answering the basic question : To answering the basic question :
whether the deeply bound state really exists?whether the deeply bound state really exists?
K-3He K-pp
clusterneutron
Missing
mass
Spectroscop
y
via neutron
Reaction
Decay???
Possible KPossible K--pp decay modespp decay modesFINUDA
fit region
K -pp?? Phy
s. R
ev. L
ett.
94, 2
1230
3 (2
005)
Invariant massInvariant massreconstructionreconstruction
+-p-+p
K-pp2370 MeV
2275 MeV
2267 MeV
0p
p
2131 MeV
2054 MeV
p
p
-
p decay mode
Dominant Decay mode
= YN
B.E. = 115 MeV
K-ppcluster
p
p
-
p decay mode
Experimental Principle Experimental Principle 33He(KHe(K--,n) reaction,n) reaction
K-3He K-pp
cluster
neutron
Missing
mass
Spectroscop
y
via neutron
Reaction
This mode allows us to investigateK-pp bound state in both
Missing mass spectroscopyand
Invariant mass reconstruction
p
p
-
Mode to decay charged particlesDecay
Invariant
mass
reconstructio
n
Signals from KSignals from K--pp and “Two nucleon absorption”pp and “Two nucleon absorption”forward neutronforward neutron
K-3He
reaction
33He(K-,n) KHe(K-,n) K--pp formationpp formationneutron
K-ppcluster
@ 1GeV/c K- andB.E. = 100 MeV
~ 1.3 GeV/c
Two nucleon absorptionTwo nucleon absorption
reactionK-3He
neutron
p (spectator)
@ 1GeV/c K-
~ 1.5GeV/c
How was decay side?How was decay side?
K-3He
reaction
33He(K-,n) KHe(K-,n) K--pp formationpp formation
Two nucleon absorptionTwo nucleon absorption
reactionK-3He
Major background, i.e. event from “two nucleon absorption process”can be identified!
neutron
K-ppcluster
p
p
-
neutron
p (spectator)
p
-
p (spectator)
Binding energy assumed as 100MeV
=> emitted proton momentum ~ 500 MeV/c
Design for the Design for the experimentexperiment
Beam Line at J-PARCBeam Line at J-PARC
K1.8BR Beam LineK1.8BR Beam Line Design for low momentum Kaon Design for low momentum Kaon
(<1.2 GeV/c ) (<1.2 GeV/c ) Single ES stageSingle ES stage Beam line length = 27.6mBeam line length = 27.6m
PrimaryProton beam
ES
Q7
D4
Q8
FFBeamSpectrometer
QDQ to focus at Final Focus (FF)QDQ to focus at Final Focus (FF) Momentum resolution ~ 2x10Momentum resolution ~ 2x10-4 -4
(position resolution of the beam (position resolution of the beam tracker assumed to be 200 tracker assumed to be 200 m (m () ) ) )
E15 DetectorE15 Detectorconceptconcept
Experiment will be performed atK1.8BR beam line.
Neutron counter
Cylindrical detector systemCDH
CDC
Solenoid Magnet
K-Proton
Proton
GEANT4 detector simulation
B.E. = 100 MeV
Expected decay mode for K-pp Expected decay mode for K-pp K-pp Λp pπ-p ➾ ➾K-pp Λp pπ-p ➾ ➾ K-pp ➾K-pp ➾ 00p ➾p ➾ Λp ➾Λp ➾ pπ-p pπ-p
Assume Assume K-ppK-pp= 60 MeV= 60 MeV
Invariant mass of Λp (MeV)
∑0 channel Λ channel
Expected detector performanceExpected detector performance
p
p
-
p decay mode
p
p
-
p decay mode
Status of the Status of the preparationpreparation
Neutron counterNeutron counter We will use same neutron counter used for We will use same neutron counter used for
KEK E549 experiment ( exist! ) KEK E549 experiment ( exist! )
20x5x150 cm3 ( W X T X L ) Plastic scintillator Configuration 16 (wide) x 7 (depth)Surface area 3.2m X 1.5m
3.2 m
1.5 m
E549 neutron counter
Solenoid Solenoid magnetmagnet
Z常伝導ソレノイド電磁石 方向磁場分布
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
-750 -500 -250 0 250 500 750 Z(mm)測定位置
(T)
磁場
強度
X=- 100,Y=0X=+100,Y=0X=- 50,Y=0X=+50,Y=0X=0,Y=0
(4361- 1)X=0,± 50,± 100,Y=0
Solenoid magnet for E15 experiment has been constructed.
Field strength; upto 0.7TSpace inside; Φ=1.2m, L=1.2m weight ; 23 t
Cylindrical Drift Cylindrical Drift ChamberChamber Design work for CDC is in progressDesign work for CDC is in progress
• He based chamber gas will be used(to reduce material budget)
Basic concept ;• Cell structure has been chosen as Hexagonal
• 1800 readout channels in total
• 15 readout layers AA’A UU’ VV’ AA’ UU’ VV’ AA
Garfi
eld
sim
ula
tion
don
e b
y D
r. F
. S
aku
ma
3He target cell
3He heat exchanger
1 K tank(1.25 K)
4 K pot(4 K)
LN2 tank
Prototype 3He target cell
Target system
R&D work for Liquid 3He target is in progress ( Dr. S. Ishimoto (KEK) and Dr. M. Iio (RIKEN) )
Event rate estimationEvent rate estimation ParametersParameters
Assume production cross section asAssume production cross section as 3He(K-,n)K-pp3He(K-,n)K-pp= 10 = 10 b/srb/sr Acceptance of Neutron counter = 30 msrAcceptance of Neutron counter = 30 msr Target thickness = 20cm, density = 0.080 g/cmTarget thickness = 20cm, density = 0.080 g/cm33
Neutron detection efficiency = 30%Neutron detection efficiency = 30% Assume 1/3 of K-pp decay in to (Assume 1/3 of K-pp decay in to (+p or +p or +p) +p) +p reconstruction efficiency in CDC = 47%+p reconstruction efficiency in CDC = 47%
Expected event rateExpected event rate 1.86x101.86x10-9-9 per an incident K per an incident K--
Event rate per dayEvent rate per day 0.8x100.8x1066 K- per 3.53s (0.7s flat top) K- per 3.53s (0.7s flat top) 24475 spill per day = 1.96x1024475 spill per day = 1.96x101010 K- per day K- per day ~ 50 events per day ~ 50 events per day
We will expect about ~1500 events in a month !!!
SummarySummary J-PARC E15 experimentJ-PARC E15 experiment
Search for simplest deeply bound kaonic nucleSearch for simplest deeply bound kaonic nuclear state, the Kar state, the K--pp bound state, pp bound state, via the via the 33He(K-,n) reaction He(K-,n) reaction
Detector construction is in progress Detector construction is in progress Solenoid magnet Solenoid magnet ;; constructedconstructed CDCCDC ; ; under real designunder real design 33He targetHe target ; ; R&D R&D Other detectorsOther detectors ;; conceptual design completed conceptual design completed
Experiment will be ready before Dec. 2008 Experiment will be ready before Dec. 2008
Thank you very muchThank you very much