investigation of strangeness photo-production near the threshold
DESCRIPTION
Investigation of Strangeness Photo-Production near the Threshold. Masashi Kaneta for the NKS2 collaboration Department of Physics, Tohoku University. Questions. Q. 1. You are: (1) an under graduate student, (2) a master course student, (3) a doctor course student, or - PowerPoint PPT PresentationTRANSCRIPT
Investigation of Strangeness Photo-
Productionnear the Threshold
Masashi Kaneta for the NKS2 collaboration
Department of Physics, Tohoku University
2
Questions
3
Q. 1You are: (1) an under graduate student, (2) a master course student, (3) a doctor course student, or (4) not a student
4
Q. 2Have you ever taken a class of nuclear physics?
5
Q. 3Do you think that
QCD can calculate everything of hadron?
6
Quark StarNeutron StarStars
compression
phasetransition
QCD Phase Diagram
Baryon density
Baryon
Big bang
Tem
pera
ture
Quark-Gluon Plasma(QGP) phase
cool
ing
element synthesis
0
Meson
phase transition
Color superconductivity?
Our world
Neutron Star
Hadron Phase
LHCCERN
7
Quark StarNeutron StarStars
compression
phasetransition
Accelerators and Facilities
Baryon density
Baryon
Big bang
Tem
pera
ture
Quark-Gluon Plasma(QGP) phase
cool
ing
element synthesis
0
Meson
phase transition
Color superconductivity?
Our world
Neutron Star
Hadron PhaseJLab
RCNPOsaka
U.
ELPHTohoku U.
RIBFRIKEN
FAIRGSI
J-PARC
Spring-8
SISGSI
AGSBNL
SPSCERN
RHICBNL
LHCCERN
SIS 200/300
GSI
AGSJ-PARC
Beam Ion Hadron Photon
LHCCERN
8
Quark StarNeutron StarStars
compression
phasetransition
My Phase Shift (Transition?)
Baryon density
Baryon
Big bang
Tem
pera
ture
Quark-Gluon Plasma(QGP) phase
cool
ing
element synthesis
0
Meson
phase transition
Color superconductivity?
Our world
Neutron Star
Hadron Phase
SPSCERN
1994-1999Graduate studentof Hiroshima Univ.
9
Pictures of NA44 Era
LHCCERN
10
Quark StarNeutron StarStars
compression
phasetransition
My Phase Shift (Transition?)
Baryon density
Baryon
Big bang
Tem
pera
ture
Quark-Gluon Plasma(QGP) phase
cool
ing
element synthesis
0
Meson
phase transition
Color superconductivity?
Our world
Neutron Star
Hadron Phase
SPSCERN
RHICBNL
ELPHTohoku U.
1999-2005PostDoc of LBNL and RIKEN-BNL Research Center
11
2002, RNC Group,LBNL
2004, RBRCChirstmanPartyhosted byT.D. Lee
LHCCERN
12
Quark StarNeutron StarStars
compression
phasetransition
My Phase Shift (Transition?)
Baryon density
Baryon
Big bang
Tem
pera
ture
Quark-Gluon Plasma(QGP) phase
cool
ing
element synthesis
0
Meson
phase transition
Color superconductivity?
Our world
Neutron Star
Hadron Phase
SPSCERN
RHICBNL
JLab
ELPHTohoku U.
2005-PresentAssistant Prof. of Tohoku Univ.
13
Outlook of This Talk
INTRODUCTION序
14
15
• General aim– Understanding the mechanism of strangeness production
• Reaction– hadron-hadron– gamma-nucleaon
• Missing resonance search w/ energy scan
• Characteristics of our experiment– Neutral channel
• K + data is not enough to make a model to predict cross section of neutral channel
• K 0 data is the KEY of the study– Threshold region
• No resonance decay effect in the final products
Strangeness Photo-production
16
g+N K+Y
17
g+p K++L(Eg threshold: 911.1 MeV)
g+p K++S0(Eg threshold: 1046.2 MeV)
g+p K0+S+(Eg threshold: 1047.5 MeV)
g+n K0+L(Eg threshold: 915.3 MeV)
g+n K0+S0(Eg threshold: 1050.5 MeV)
g+n K++S-(Eg threshold: 1052.1 MeV)
Data in the Marketg+nK0+L
g+nK++S-
g+nK0+S0
LEPS experiment:differencial cross section in Eg=1.5-2.4 GeVwith polarized photon beamPRL97 (2006)082003
NKS experiment:differencial cross sectionin Eg=0.8-1.1 GeVPRC78(2008)014001
CLAS experiment:differencial cross section in Eg=1.1-3.6 GeVPLB688(2010)289
g+pK0+S+
Phys.Rev.C73(2006)035202
Phys.Rev.C73(2006)035202
Phys.Lett.B464(1999)331SAPHIR
18
g+pK++L
g+pK++S0
Experiments to investigateStrangeness Photo-Production
at LNS/ELPH, Tohoku Univ.
NKSNKS2
and
19
NKS2000-2004:
Using TAGX spectrometerReconstruct K0
S from +- decayThe first measurement of K0 cross sectionfrom g+nK0+L reaction [Phys.Rev.C78(2008)014001]
Neutral Kaon Spectrometer
20
Experiments to investigateStrangeness Photo-Production
at LNS/ELPH, Tohoku Univ.
NKS22005
Construction of new spectrometer2006-2007
Data taking
2008-2009Upgrade inner detectors
2010Data taking
21
Experiments to investigateStrangeness Photo-Production
at LNS/ELPH, Tohoku Univ.
22
The NKS2 Collaboration• Department of Physics, Tohoku University
B. Beckford, T. Fujii, Y. Fujii, T.Fujibayashi, K. Futatsukawa,O. Hashimoto, A. Iguchi, H. Kanda, Kaneko, M. Kaneta,T. Kawasaki, C. Kimura, S. Kiyokawa, T. Koike, K. Maeda,N. Maruyama, Matsubara, Y. Miyagi, K. Miwa, S.N. Nakamura, A. Okuyama, H. Tamura, K. Tsukada, N. Terada, F. Yamamoto
• Research Center of Electron-Photon Science, Tohoku University K. Hirose, T. Ishikawa, T. Tamae, H. Yamazaki
• Department of Nuclear Science, Lanzhou University, Lanzhou, ChinaY.C. Han, T.S. Wang
• Nuclear Institute, Czech RepublicP. Bydzovsky, M. Sotona
博士課程前期 (修士で卒業 )博士課程後期 (Dr.Sc.を所得 )
EXPERIMENT実験
23
2424
青葉山キャンパス
電子光理学研究センター
Research Center of Electron-Photon Science(ELPH), Tohoku Univ.
Linac (Max 200 MeV)
Stretcher Booster Ring (Max 1.2 GeV)
25
BM4 tagger
BM5 tagger
to the GeV gexperimental hall
NKS2
Radiator (Carbon wire) to make Bremsstrahlung
B
Photo
n Bea
mOrb
it ele
ctron
(1.2
GeV
)
Scattered electron (0.1-0.4 GeV)
Tag F
Tag B
Sweep magnet
Photon Beam line – top view
26
g beam
vacuum of STB-ring
CollimatorRejection of beam halo
Sweep MagnetRejection of e+e-
Dipole Magnet
Target SystemMaking of liq. D2 target
Vacuum Region Suppress of pair creation
Liquid D2 Target
Lead glass counterMeasurement of tagging efficiency
Photon Beam line – side view
BPM
27
NKS2 Detector Setup• Dipole Magnet
– B=0.42 [T] at the center
• Inner Hodoscope– Trigger– Start timing of TOF
• Outer Hodoscope– Trigger– Stop timing of TOF
• Straw Drift Chamber– Tracking (2D)
• Cylindrical Drift Chamber– Tracking (3D)
• Electron Veto Counter
g beam
1.0 m
A vertical cross section along beam
28
NKS
NKS2
29
g+d K0+L+(p)
K0S ++-
L -+p
Reaction
Decay Mode
TriggerPhoton: Tagger hit2 charged particle: nHit on IH2 and nHit on OH2Background rejection: Veto of e from upstream
Trigger rate: ~1 kHz at 2 MHz tagger rateDAQ efficiency ~70%
RECENT RESULTS最近の結果
30
31
Particle Identification
1/b
char
ge×m
omen
tum
[GeV
/c]
Mass square [GeV2/c4]
+
-
p d
+
p
d
32
Background Rejection
- decay volume cut
Target cell
No cut
Decay vertex resolution1.1mm for
horizontal4.2mm for
vertical
33
Invariant Mass Distributions
34Error bars : statistical only
Differential Cross SectionE
g = 0.90 – 1.00 GeV
Eg = 1.00 – 1.08 G
eVds
/dp La
b [mb
/(GeV
/c)]
pLab [GeV/c]
g + d K0 + X (mainly g + n K0 + L)
Error bars : statistical only
Eg = 0.90 – 1.00 G
eVE
g = 1.00 – 1.08 GeV
ds/d
p Lab [mb
/(GeV
/c)]
pLab [GeV/c]
35
Differential Cross Sectiong + d L + X (mainly g + n K0 + L
and g + p K+ + L)
COMPARISON WITH MODELSモデルとの比較
36
Models near the threshold
Effective Lagrangian Approachalso knows as Isobar model
37
Rigge Plus Resonance Model
Theoretical Study: Effective Lagrangian Approach
• Hadron coupling– Isospin symmetry
• Electromagnetic (photo) coupling– Helicity amplitude
• Charged and neutral nucleon resonances
– Decay width• Charged and neutral Kaon resonances
g
g
g
N
N
N
K
K
K
s channel
t channel
u channel
YNN*
D, D*
K,K*,K1
Y
YYY*
g
N
KContact term
Y 38
- 0.45 in Kaon-MAID, estimated from gpK0S+ data Free parameter in Saclay-Lyon A
53.1)()()( *
00** - ++ g
ggKKgKKgKKr
)( 1 gKKr
• However, the decay width of K1 resonance is not known
Characteristics of KL Channel - comparison with KS
39
g
N
K
YN, N*, D, D* , ....
s channel
In the s-channel exchange, KL: N* KS: N* and D*
Characteristics of K0L Channel- comparison with K +L
40
g
N
K
t channel
K, K*, K1, . . .
Y
g
N
K
u channel
YYY*
.
.
g
N
K
YNN*
DD*
.
.
s channel
No contribution of charge term in coupling constants
Models• Kaon-MAID
– T.Mart, C.Bennhold– PRC61 (2000) 012201(R)
• Saclay-Lyon A– T. Mizutani et al. – PRC58 (1998) 75
41
Kaon-MAID
Saclay-Lyon A
Inputdata
g+pK++L ○ ○g+pK++S0 ○g+pK0+S+ ○
Resonancesincluded in the model
N(1650) S11 ○N(1710) P11 ○N(1720) P13 ○ ○D(1900) S31 ○D(1910) P31 ○K*(892) ○ ○K1 (1270) ○ ○L(1405) ○L(1670) ○L(1810) ○S(1660) ○
Hadronic form factor ○contact term ○
42Error bars : statistical only
Comparison with Isobar Modelsds
/dp La
b [mb
/(GeV
/c)]
pLab [GeV/c]
g + d K0 + X, Eg = 0.90 – 1.00 GeV
Kaon-MAID All K0 L K0 S0
K0 S+
Saclay-Lyon A rkk = -1.0 rkk = -1.5 rkk = -2.0
Kaon-MAID All
43
ds/d
p Lab [mb
/(GeV
/c)]
pLab [GeV/c]
Kaon-MAID All K0 L K0 S0
K0 S+
Saclay-Lyon A rkk = -1.0 rkk = -1.5 rkk = -2.0
Kaon-MAID All
Comparison with Isobar Modelsg + d K0 + X, Eg = 1.08 – 1.08 GeV
Error bars : statistical only
Invariant AmplitudeM = Mbackground (Regge) + S Ms(Isobar)
Phys.Rev.C73 045207 T. Corthals et al.
44
Regge Plus Resonance (RPR) Model
g
N
K
YN, N*, D, D* , ....
s channel
N(1650) S11 , N(1710) P11 N(1720)P13, N(1720) P13 N(1900) D13D(1900) S31 D(1910) P31
K*(892) TrajectoryK(494) Trajectory
4
3
2
1
0
a(t)
0 1 2 3 4 5 6
t [GeV/c2]
Calculation of RPR Model Eg = 0.9-1.0 GeV, cosqK0
Lab = 0.9-1.0
Nucleon Resonances in the KL process N(1650) S11, N(1710) P11, N(1720) P13, N (1900) P11, N(1900) D13
N(1900) D13 : Missing Resonance
No data to helicity amplitude of N(1900) D13
→ From -2.0 To 2.0 (Cyan Line 0.0)
P.Vancraeyveld et al.: private communication
Our results are two times larger than the calculations of RPR at least
45
Comparison with RPR Model
46
K0L: Backward Distributions (fitting results)K+L: Forward Distributions (SAPHIR, CLAS)
SAPHIR: K. H. Glander et al., Eur. Phys. J., A19:251–273, 2004.CLAS: R. Bradford et al., Phys. Rev., C73:035202, 2006.
Kaon Angle distribution in CM
SUMMARYまとめ
47
48
Investigating strangeness photo-productionvia g + n K 0
S + L channelusing the NKS2 spectrometer at ELPH, Tohoku Univ.
Differential cross sections of K 0S and L in g+d
K 0S
Larger angle coverage than previous experiment L
The first measurement K 0
S + L total cross section estimatedsimilar shape to K +
+ L as a function of Eg Suggestion from comparison of data with models
Angular distributionbackward enhance in K 0
S + L(K + + L: slightly forward peak)
Detector upgrade was done and we took new data
49
Upgrade Project
To increase acceptance Inner detectors are replaced
byVertex Drift Chamber (VDC)New Inner Hodoscope (IH)
50
VDCIH