spectroscopic study of lambda(1405) via the (k-,n)reaction on deuteron
DESCRIPTION
Spectroscopic study of Lambda(1405) via the (K-,n)reaction on deuteron. Baryons’[email protected] 2010/12/10 Shun Enomoto RCNP,Osaka.University For the J-PARC E31 collaboration. Contents. Introduction - Λ (1405) -(K - ,n) reaction on deuteron. J-PARC E31 experiments -Experimental method - PowerPoint PPT PresentationTRANSCRIPT
Baryons’[email protected] 2010/12/10
Shun EnomotoRCNP,Osaka.University
For the J-PARC E31 collaboration
Spectroscopic study of Lambda(1405) via the
(K-,n)reaction on deuteron.
1
• Introduction -Λ(1405) -(K-,n) reaction on deuteron.
• J-PARC E31 experiments -Experimental method(identify I=0 state in KbarN->πΣ process)
• Preparation status -Development detector
• Summary
Contents
2
Introduction
3
• 3quark?5quark?
• KbarN1406.5MeV/c2[one pole?]
Deeply bound KbarN state.Y.Akaishi & T.Yamazaki, Phys. Rev. C65(2002) 04405.Y.Akaishi & T.Yamazaki, Phys. Lett. B535 (2002) 70
1420MeV/c2[two pole?]Chiral Unitary Model predicted.
T. Hyodo, D. Jido, and A. Hosaka, Phys. Rev. Lett. 97, 192002(2006);T. Hyodo, D. Jido and A. Hosaka, Phys. Rev. D75, 034002(2007).T. Hyodo and A. Weise, Phys. Rev. C77, 035204(2008)
Λ(1405)
4
I=1
I=0
∑(1192),1/2+
∑*(1385),3/2+
Λ(1116),1/2+
Λ(1405),1/2-
Λ(1520),3/2- KN(1432)
-27MeV
A spectroscopic study of Λ(1405) directly coupled to KbarN is desired. KbarN scattering below KbarN threthold.→d(K-,n) reaction
Motivation・ To clarify whether Λ(1405) is KbarN resonant state.
the(K-,n) reaction on Deuteron.
pn
2H
n
∑
π
K-
t
Y*K
5
Non-resonantI=1
Σ*(1385)P-waveI=1 Λ*(1405)?
Y*(mass)
S-waveI=0,1
1420MeV/c2?
1405MeV/c2?
KN :1432MeV
Λ(1405) and BG(NR/∑*)• S-wave,I=0 → Λ*(1405)→π0∑0,π-∑+ ,π+∑-
• S-wave,I=1 → non-resonant(NR)• P-wave,I=1 →∑*(1385) → π0Λ,π-∑+ ,π+∑-
Purely I=0
J.Yamagata-Sekihara,T.Sekihara,and D.Jido,paper in preparation
Possible ID of I=0 in KbarN->π∑Possible decomposition of I=0 amplitude.
J-PARC E31 experiments
6
J-PARC E31 Collaboration
7
• S. Ajimura1, G. Beer2, H. Bhang3, M.Bragadireanu8,P. Buehler4, L. Busso5,6, M. Cargnelli4, S. Choi3, C. Curceanu8, S. Enomoto1, D. Faso5, H. Fujioka13, Y. Fujiwara12, T. Fukuda11, C. Guaraldo8, T. Hashimoto12,R. Hayano12, T. Hiraiwa 13, M. Iio9,K. Inoue1, N. Ishibashi17, T. Ishikawa12, S. Ishimoto14, T. Ishiwatari4, K. Itahashi9, M. Iwai14, M. Iwasaki9,10,S. Kawasaki1, P. Kienle15, H. Kou10,J. Marton4, Y. Matsuda12, Y. Mizoi 10, O. Morra5, T. Nagae13, H. Noumi 1, H. Ohnishi9, S. Okada8, H. Outa9,Y. Sada13, A. Sakaguchi17, F. Sakuma9, M. Sato12, M. Sekimoto14,H. Shi12, D. Sirghi8, F. Sirghi8, S. Suzuki14, T. Suzuki12, H. Tatsuno12, M. Tokuda10, D. Tomono9, A. Toyoda14, K. Tsukada9, E. Widmann4, T. Yamazaki9,12, K. Yoshida17, H. Yim3, B. Wünschek4, J. Zmeskal4
• 1. Research Center for Nuclear Physics, Osaka University, Japan • 2. University of Victoria, Canada, 3. Seoul National University, South Korea• 4. Stefan Meyer Institut fur subatomare Physik, Austria, • 5. INFN Sezione di Torino, Italy , 6.Universita’ di Torino, Italy• 8. Laboratori Nazionali di Frascati dell’INFN, Italy• 9. RIKEN, Japan, 10. Tokyo Institute of Technology, Japan • 11. Osaka Electro-Communication University, Japan, 12. University of Tokyo, Japan • 13. Kyoto University, Japan, 14. High Energy Accelerator Research Organization
(KEK), Japan • 15. Technische Universitat Munchen, Germany, 16. INAF-IFSI, Sezione di Torino, Italy• 17. Osaka University, Japan
• Spectroscopic study of Hyperon Resonances below KbarN threthold via the (K -,n) reaction on Deuteron.
15m
Neutron counter(TOF)ΔT~150ps
Decay Particle
Detector(CDS)
K - 1.0GeV/c
n~1.3GeV/c
Λ(1405)
2)( ndKX PPPMM
Target(D)
・ To measure Λ* mass spectra by Missing Mass .
・ To Identify Λ* decay mode by CDS
3He(K-,n)”Kpp” reactionJ-PARC E15@J-PARC K1.8BR
Σ-π+,Σ+π-→I=0 Λ* I=1 NR I=1 Σ*Σ0π0 →I=0 Λ*Λπ0 →NR or Σ*
J-PARC E31 Experiments
8
・ σMM~9MeV/c2 at PK- = 1.0GeV/c
15m
K-
beam beam spectrometer
J-PARC K1.8BR
9
neutron counter
Rearra
nge
Decay particle detector(CDS)
Liq.D target
2010/10/25
case1:π+∑- and π-∑+
Λ(1405)→ ∑ +π-→ (nπ+) π-
∑ -π+→ (nπ-)π+
10
Identification of Λ* decay mode.
case2: π0∑0 and Λπ0(NR/∑*) Λ(1405) →∑ 0π0→Λγπ0→(pπ-)γ π0
NR/Σ(1385) →Λπ0 →pπ-π0
target
CDC(Drift chamber)
ZVC
Solenoid magnet
CDH
π-π+
n(~1.3GeV/c)
Λ(1405)→ ∑ +π-→ (nπ+ )π- or ∑-π+→ (nπ-) π+
∑+
n
K-=1.0GeV/c
Λ(1405)
0.1~0.2GeV/c0.1~0.3GeV/c
0.5T
The J-PARC E15 setup is quite suitable to detect π.
Detection of the Λ* ->∑-π+ and ∑+π-modes
11
Identification of the decay modes:Λ* ->∑-
π+ or ∑+π-
1340 1360 1380 1400 1420 1440 14600
0.1
0.2
0.3
0.4
0.5
0.6
S-pi+cut
S+pi-cut
Hyperon mass (MeV/c2)
effici
ency
1340 1360 1380 1400 1420 1440 14600
0.0020.0040.0060.0080.01
0.0120.0140.016
X(MeV/c2)
mis
sID
(rat
io)
MissingMass2(MeV/c2)2
22 )(
PPPPMM ndK
(∑+π-) MM(mass)
(Σ-π+): MM(Σ-
mass)
Γ(Λ*→∑+π-)/Γ(Λ*→∑-π+) ~ 1
missID(Σ+π-)=(∑-π+[①])/(Σ+π-[②])
×103
②
Σ+π-
Σ-π+
Σ+π- Σ-π+
12
①①
KbarN
Λ*→∑0π0 ,(∑*→Λπ0)
target
CDC(Drift chamber)
ZVC
Solenoid magnet
CDHπ-:~200MeV/c
P:~500MeV/c
Λ(1405)→∑0 π0→Λγπ0→ (p π-)γ π0
NR/∑(1385)→Λπ0→(pπ-)π0
K-=1.0Gev/cπ0
∑0n(~1.3GeV/c)
Backward Protondetector(BPD) & chamber(BPC)
BPD measures to momentum of proton by TOF methods. 13
ID & Efficiency for Λ*->π0Σ0
222 )()( PPPPPPMM pndKYY
P:fourth momentum
MM2(MeV/c2)2
Λ*->π0Σ0
([π0+γ]mass)
Σ*->Λπ0(π0mass)
Γ(Λ*)/Γ(Σ*) ~ 1
Proton DetectorResolution(σ)
×103
Λ*->∑0π0
Λπ0(contamination)=(Λπ [②])/(Λπ)
Λ(1405)→∑0 π0→Λγπ0→(p π-)γ π0
NR/∑(1385)→Λπ0→pπ-π0
① ②
Σ*->Λπ0 contamination
14
effici
ency
Hyperon X mass[MeV/c2]
Preparation status
15
Backward Proton Detector(BPD)
Prototype(BPD):5mm2×400mm Scintillator with MPPC-50μm
MPPC-50μmσ=246.4ps
(T0-PD)
Meantime[ns]
Beam test:Time Resolution(BPD-T0) σ~250ps
• TOF for proton->Scintillation Hodoscopes
with MPPC.
16
117m
m
168m
m
ASD base
Backward Proton Chamber(BPC)
Vertex Detector for Λ->pπ-
-> determine the reaction point(z vertex) for better Pn measurement in Λ*-> π0Σ0
• Wire gap 3.6mm(xx’yy’xx’yy’:8layers)• Active area φ111.6mm(readout:15ch(1layer))• Outside diameter φ=168mm(z-TPC inside
diameter φ=170mm) 17
• We propose to study Λ(1405) hyperon resonance via the d(K-,n) reaction.
→To investigate Λ(1405) in the coupled channel
KbarN->πΣ system.
• We found that the J-PARC E15 setup has sufficient detection efficiency to identify Λ*->π+Σ- and Λ*->π-Σ+ clearly.
• We introduce BPD & BPC to identify Λ*->π0Σ0
clearly .
Summary
18Thank you
Back up
19
~2011:Summer;BPC & BPC will be ready
2011:Autumn~;Engineering run start?
201? ;E31 experiment start?
Future plan
20
Intensity 30GeV-27kW(6s)Secondary beam K-:1.0GeV.cBeam intensity(Ib) 2.0*10^5per pulse 6s spill intervalCross section(dσ/dΩ) 220μb/sr
97128
Λ(1405)→π+∑-→π+π-nΛ(1405)→π-∑+→π-π+nΛ(1405)→π0∑0→π0π-p
Solid angle(ΔΩ) 0.020srDecay mode efficiency(εM)
0.320.160.015
Λ(1405)→π+∑-→π+π-nΛ(1405)→π-∑+→π-π+nΛ(1405)→π0∑0→π0π-p
Target 4.1*10^23 Liquid deuteron(8cm)Yield(120shift) ~19200
~4800~350
Λ(1405)→π+π-nΛ(1405)→π-π+nΛ(1405)→π0π-p
AMRtb ddnIY
R:reconstruction(0.24)A:analysis(0.9)
Yield estimation (E31 experiment)
10deg4deg
0deg
D(K-,n)X(1400)
fmMeVcfmrprL
cMeVPcMeVP CMNKLabNK
200~,1~,1
/160~,/250~ )()(
S-wave KbarN scattering is dominant at θn =0 degree.
P_KN
• Simple the reaction mechanism.->d(K-,n)π+Σ- at PK-=800MeV/c
K- D nKN
22
1340 1360 1380 1400 1420 1440 14600
0.1
0.2
0.3
0.4
0.5
0.6 eff for Sig-pi+eff. for Sig+pi-
Y* Mass (MeV/c2)
effici
ency
/Mis
-ID r
atio
23Contamination(Mis-identification) ~a few%
• Clebsch-Gordan coeficients
Λ(1405)/Σ(1385)_1
31
32
210,0
210
210,1
61
32
610,2
00
00
• Σ(1385)[I=1] can not decay π0Σ0 .
)1,1(),0,1(),1,1(,,
)1,1(),0,1(),1,1(,,
,,,
0
0
2211,, 2211
mjmjCMJ MJmjmj
24
target
CDC(Drift chamber)
ZVC
Solenoid magnet
CDH
π-π+
n(~1.3GeV/c)
Λ(1405)→ ∑ +π-→ (nπ+ )π- or ∑-π+→ (nπ-) π+
∑+
n
K-=1.0GeV/c
Λ(1405)
0.1~0.2GeV/c0.1~0.3GeV/c
angle
mom
entu
m
0.5T
Σ+π- Σ-π+π-
The J-PARC E15 setup is quite suitable to detect π.
Detection of the Λ* ->∑-π+ and ∑+π-modes
25
Λ*→∑0π0 ,(∑*→Λπ0)
target
CDC(Drift chamber)
ZVC
Solenoid magnet
CDHπ-:~200MeV/c
P:~500MeV/c
Λ(1405)→∑0 π0→Λγπ0→ (p π-)γ π0
NR/∑(1385)→Λπ0→(pπ-)π0
K-=1.0Gev/cπ0
∑0n(~1.3GeV/c)
proton
angle
mom
entu
m
Σ0π0 Λπ0
Backward Protondetector(BPD) & chamber(BPC)
BPD measure s to momentum of proton TOF methods. 26
• Λ(1405)→π-Σ+→π- (pπ0) [51.57%] or π-(nπ+) [48.31%] π+Σ-→π+(nπ-)[99.84%] π0Σ0→π0Λγ→π0(nπ0)[35.8%] or
π0(pπ-)γ[63.9%]
• Σ(1385)→πΛ[87.0%] →πΣ[11.7%]
Decay mode[Λ(1405)/Σ(1385)]
27
Cylindrical Detector System• A newly developed system for invariant mass
study
28
Expected mass resolution : - ~ 3.0 MeV/c2 for L - ~ 13 MeV/c2 for K-pp( cdc = 200 mm / Field : 0.5 T)
Neutron counter
29
3.2 m
1.5 m
E549 neutron counter
support frame for E15
rearrange
• 20 x 5 x 150 cm3 Plastic Scintillator• Configuration : 16 (wide) x 7 (depth)• Surface area : 3.2m x 1.5m• missing mass resolution for K-pp = 9.2 MeV/c2 (Pn=1.3 GeV/c, TOF=150 ps)
Λ*
J.Yamagata-Sekihara,T.Sekihara,and D.Jido,paper in preparation
D(K-,n)π+∑- (PK=800MeV/c)
30
10deg4deg
0deg
D(K-,n)X(1400)
fmMeVcfmrprL
cMeVPcMeVP CMNKLabNK
200~,1~,1
/160~,/250~ )()(
L=0,s-wave の反応断面積が大きい
KN の運動量
中性子の運動量
31
Motivation
・ To clarify whether Λ(1405) is KbarN resonant state.
KbarN scattering below KbarN threthold.→d(K-,n)Λ* reaction is KbarN direct reacion.
the(K-,n) reaction on Deuteron.
pn
2H
n
∑
π
K-
t
Y*
K
32
Non-resonantI=1
Σ*(1385)P-waveI=0 Λ*(1405)?
Y*(mass)
S-waveI=0,1
1420MeV/c2?1405MeV/
c2?
KN :1432MeV
Possible ID of I=0 in KbarN->πΣ• S-wave,I=0 → Λ*(1405)→π0∑0,π∑+ ,π+∑-
• S-wave,I=1 → non-resonant(NR)• P-wave,I=1 →∑*(1385) → π0Λ,π-∑+ ,π+∑-
33
the(K-,n) reaction on Deuteron.
Λ*
J.Yamagata-Sekihara,T.Sekihara,and D.Jido,paper in preparation
D(K-,n)π+∑- at PK=800MeV/cEnhancement of Λ* production
at θn=0BackGround from Σ* will be reduced
Σ*
S-wave KbarN scattering is dominant at θn = 0 degree
Possible decomposition of I=0 amplitude.
Purely I=0