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HES-HKS analysis meeting
Toshi Gogami5Mar2014
Contents
Cross section & Λ binding energy 12C(e,e’K+)12
ΛB10B(e,e’K+)10
ΛBe7Li(e,e’K+)7
ΛHeMissing mass spectra
9Be(e,e’K+)9ΛLi
52Cr(e,e’K+)52ΛV
Definition of differential cross section
Number of virtual photonincluding HES acceptance
Number of target nucleus EfficienciesHKS acceptance
NOTE
Cut conditions
• 0.80 < pe < 0.98 [GeV/c]
• Abs(m2-m2K) < 0.3
• -1.0 < ctime < 1.0
NOTE
Efficiencies and correction factors• Efficiencies• DAQ• Trigger• Tracking• K+ selection
• AC, WC, m2,
• Correction factors• K+ decay (momentum dependent)• Solid angle (momentum dependent)• K+ absorption • Event loss due to matrix and energy loss
• Small effect for hypernucelus systematic errors• Acceptance (real and simulation)
• Small discrepancy systematic error
NOTE
Systematic error for cross-section
• Statistical error in simulation• Position accuracy of collimator (1mm)• Acceptance discrepancy between sim. and real
Obtained by blind analysis
Systematic error for binding energy
Blind analysis Date: 2/25 – 3/4Time: 92.5 hoursInitial matrices: distorted by hand
Momentum: Λ, Σ0 and 12ΛB
Angle : Λ and Σ0
(Different distortion pattern from previous study was tested)
Simple report click here
Systematic error for binding energy
Blind analysis Date: 2/25 – 3/4Time: 92.5 hoursInitial matrices: distorted by hand
Momentum: Λ, Σ0 and 12ΛB
Angle : Λ and Σ0
(Another distortion pattern was tested)Before After
IN PROGRESS
12C(e,e’K+)12ΛB spectrum
Count Cross sectionVirtual photon fluxEfficienciesAcceptance
Λ binding energy for 12C(e,e’K+)12ΛB
Peak - BΛ [MeV] N [nb/sr]1 -11.380.02 76528 97.83.611.52 -8.390.05 14912 19.01.52.23 -5.200.09 13511 17.21.42.04 -1.700.07 9410 12.01.31.45 -0.430.03 65826 84.13.39.96 0.470.06 21014 26.81.73.2
(FWHM: 500 keV)
Click to see previous results
12ΛB comparison
Experiment
θγKLab [degree] -BΛ [MeV] Cross section [nb/sr] Extracted value from
Motoba-san’s predictionE05-115 6.8 -11.38 ± 0.02 ± sys. error 97.8 ± 3.6 ± 11.5 75
E01-011 5.8 -11.40 ± 0.01 ± 0.04 101 ± 4.2 (+ 38 – 31) 85
E89-009 0 -11.52 ± 0.35 140 ± 17 ± 18 120
Emulsion -11.37 ± 0.06 N/A
SΛ
Experiment
θγKLab [degree] -BΛ [MeV] Cross section [nb/sr] Extracted value from
Motoba-san’s prediction
E05-115 6.8 -0.43 ± 0.03 ± sys. error 84.1 ± 3.3 ± 9.9 85
E01-011 5.8 -0.41 ± 0.01 ± 0.13 94 ± 4.0 ±35 96
E89-009 -0.49 ± 0.16 N/A
pΛ
10B(e,e’K+)10ΛBe spectrum
Count Cross sectionVirtual photon fluxEfficienciesAcceptance
Λ binding energy for 10B(e,e’K+)10
ΛBe
Peak - BΛ [MeV] N [nb/sr]1 -8.550.07 20314 17.31.21.32 -5.870.17 17213 14.71.11.13 -4.960.51 537 4.50.60.34 -2.280.13 14012 12.01.00.95 -1.100.16 10710 9.10.90.76 0.270.14 11711 10.00.90.77 2.250.07 22515 19.21.31.48 11.120.15 10410 8.90.90.7
(1) T.Cantiwell et al., NPA236 (1974) 445-456(2) M.Juric et al., NPB52 (1973) 1-30
(FWHM: 780 keV)
Old data (3 points)8.910.60(1)
8.310.61(1)
9.300.26(2)
Λ binding energy for 10B(e,e’K+)10ΛBe
(FWHM: 780 keV)
-8.84 without CSB-8.76 with CSBHiyama’s calc.
Motoba’s calc.
Peak - BΛ [MeV] N [nb/sr]
1 -8.550.07 20314 17.31.21.3
2 -5.870.17 17213 14.71.11.1
3 -4.960.51 537 4.50.60.3
4 -2.280.13 14012 12.01.00.9
5 -1.100.16 10710 9.10.90.7
6 0.270.14 11711 10.00.90.7
7 2.250.07 22515 19.21.31.4
8 11.120.15 10410 8.90.90.7
Old data (3 points)8.910.60(1)
8.310.61(1)
9.300.26(2)
7Li(e,e’K+)7ΛHe spectrum
Count Cross sectionVirtual photon fluxEfficienciesAcceptance
Λ binding energy for 7Li(e,e’K+)7ΛHe
E01-011: -5.680.030.25 MeV
Peak - BΛ [MeV] N [nb/sr]1 -5.740.10 45021 17.30.82.82 -3.840.16 38220 14.70.82.4
(FWHM: 1300 keV)
-5.36 without CSB-5.16 with CSBHiyama’s calc.
About target thickness click here
Λ binding energy for 7Li(e,e’K+)7ΛHe
E01-011: -5.680.030.25 MeV
(FWHM: 1300 keV)
-5.36 without CSB-5.16 with CSBHiyama’s calc.
Peak - BΛ [MeV] N [nb/sr]
1 -5.740.10 45021 17.30.82.8
2 -3.840.16 38220 14.70.82.4
Missing mass spectra
9Be(e,e’K+)9ΛLi
52Cr(e,e’K+)52ΛV
9Be(e,e’K+)9ΛLi spectrum
Count Cross sectionVirtual photon fluxEfficienciesAcceptance
9Be(e,e’K+)9ΛLi spectrum
9Be(e,e’K+)9ΛLi spectrum
M.Sotona and S.Frullani, PTP supplement No.117 (1994)
9Be(e,e’K+)9ΛLi spectrum rough
comparisonJ.J.LeRose et al., NPA804(2008)116-124 F.Cusanno et al., NPA835(2010)129-135
Hall-AHall-A
Hall-C Hall-C
Missing mass spectrum of 52Cr (e,e’K+)52
ΛV
Accidental background
sΛ (?)
JLab E05-11552Cr (e,e’K+)52
ΛV
Missing mass spectrum of 52Cr (e,e’K+)52
ΛV
Accidental background
JLab E05-11552Cr (e,e’K+)52
ΛV
Missing mass spectrum of 52Cr (e,e’K+)52
ΛV
Accidental background
JLab E05-11552Cr (e,e’K+)52
ΛV
Summary and Outlook
• Summary• Status of spectra
• Outlook• Blind analysis systematic error for binding energy• D’s thesis
END
Backup
Λ binding energy for 12C(e,e’K+)12ΛB
Peak -B [MeV] Number of event
Cross section [nb/sr]
1 -11.40 ± 0.03 657±26 83 ±3
3 -8.37 ± 0.10 135±11 17 ±1
4 -5.15 ± 0.18 118±11 15 ±1
5 -1.67 ± 0.23 116±11 14 ±1
2 -0.38 ± 0.04 631±25 82 ±3
6 +0.82 ± 0.09 240±15 31 ±2
Only statistical errors
( FWHM ~ 0.89 MeV )
PREVIOUS (1/10)
Λ binding energy for 12C(e,e’K+)12ΛB
Peak - BΛ [MeV] N [nb/sr]1 -11.380.02 76528 97.83.611.52 -8.390.05 14912 19.01.52.23 -5.200.09 13511 17.21.42.04 -1.700.07 9410 12.01.31.45 -0.430.03 65826 84.13.39.96 0.470.06 21014 26.81.73.2
(FWHM: 500 keV)
Present (2/28)
Gaussian fitting
Gaussian fit 8020 events (/10000)
~80% counting efficiency
SIMULATION (after matrix tuning)12C, 87.5 mg/cm2
12ΛB (-BΛ=-11.37 MeV)
[GeV]
[ Cou
nts
/ 100
keV
]
Number of events after matrix tuning
Counting efficiency is good enough !
SIMULATION (after matrix tuning)12C, 87.5 mg/cm2
12ΛB (-BΛ=-11.37 MeV)
Voigt function
Systematic error for cross-section
About Lithium target thickness
ELOG Entry: 185809Lithium 7 (325.2mg, 0.982cm2 331.2mg/cm2)Thickness of Lithium is 3.9mm, using density of 0.535g/cm3, it is 207mg/cm2.
For energy lossFor cross-section
A photograph before mounting already black….. Nitride ? Lithium nitridation test will be done.
Go back
Carbon target
Boron target
Lithium target
Chromium target
9Be(e,e’K+)9ΛLi
To be update
(This is made by old matrix
)
Differential cross section of 10B(γ*,K+)10
ΛBe
Peak -B [MeV] Number of event
Cross section [nb/sr]
1 -8.66 ± 0.08 141±12 11.6 ±0.9
2 -7.81 ± 0.23 51±7 4.3 ±0.7
3 -6.08 ± 0.09 139±12 11.8 ±1.0
4 -5.03 ± 0.14 78±9 6.5 ±0.7
5 -1.98 ± 0.10 156±13 13.0 ±0.9
6 -0.11 ± 0.16 123±11 10.0 ±0.8
7 2.23 ± 0.07 188±14 15.9 ±1.1
8 11 .14± 0.13 94 ± 10 7.8 ±0.8
( FWHM ~ 0.8 MeV )
PREVIOUS (1/10)
Comparison with old data
MeV
PREVIOUS (1/10)
Differential cross section of 10B(γ*,K+)10
ΛBe
Peak -B [MeV] Number of event
Cross section [nb/sr]
1 -8.66 ± 0.08 141±12 11.6 ±0.9
2 -7.81 ± 0.23 51±7 4.3 ±0.7
3 -6.08 ± 0.09 139±12 11.8 ±1.0
4 -5.03 ± 0.14 78±9 6.5 ±0.7
5 -1.98 ± 0.10 156±13 13.0 ±0.9
6 -0.11 ± 0.16 123±11 10.0 ±0.8
7 2.23 ± 0.07 188±14 15.9 ±1.1
8 11 .14± 0.13 94 ± 10 7.8 ±0.8
( FWHM ~ 0.8 MeV )
-8.84 without CSB-8.76 with CSBHiyama’s calc.
Motoba’s calc.
PREVIOUS (1/10)
Contribution to missing mass resolution
One of results of blind analyses
Missing masses with initial matrices
Simply calculated by quadratic sum
Differential cross section of 12ΛB by
Motoba-san
DWIA , Eγ = 1.5 GeV
Differential cross section predicted by Motoba-san
Motoba-san’s calc.12
ΛB g.s. (1- , 2-)
θLabγK [degree]
[nb/
sr]
Angular distribution in simulation (θLab
γK)Accepted events by HES-HKS with uniform generation
Expected distribution(Weighted by prediction)
SIMULATION
Motoba-san’s calc.12
ΛB g.s. (1- , 2-)
θLabγK [degree]
Nor
mal
ized
inte
nsity
θLabγK [degree]
[Cou
nts]
Predicted cross section in our acceptance
SIMULATION SIMULATION
Accepted events by HES-HKS with uniform generation
Expected distribution(Weighted by prediction)
6.8 degree
7.4 degreeMean values
75 nb/sr75 nb/sr
θLabγK [degree] [nb/sr]
Value usedfor comparison !!
Matrix optimization with 7ΛHe
Toshi Gogami27Feb2014
Histogram sample
7ΛHe
Background
7ΛHe + background
Results
# (Number of LOOPs) 1 (10) 2 (10) 3 (5) 4 (15)
Angle ( Λ : Σ0 : 7ΛHe ) 1:1:1 1:1:1 1:1:9 -
Momentum(Λ : Σ0 : 12ΛB) - - - 1:1:1
7ΛHe convergence to Fitting mean Fixed
(generated point)Fixed(generated point)
-
Width of 7ΛHe (FWHM)
[keV/c2]1060 +/- 70 1030 +/- 70 980 +/- 60 1030 +/- 70
( Matrix tuning was started with not-distorted matrices.)
#3#2#1 #4
Contribution to missing mass resolution
One of results of blind analyses
Missing masses with initial matrices
Simply calculated by quadratic sum
New blind analysis results
4Mar2014Toshi Gogami
Blind analysis
Date: 2/25 – 3/4Time: 92.5 hoursInitial matrices: distorted by hand
Momentum: Λ, Σ0 and 12ΛB
Angle : Λ and Σ0
Missing mass spectra with distorted matrices
Λ Σ0 7ΛHe
52ΛV12
ΛB10ΛBe
Spectrum comparison
Before After
Results
FWHMFitting mean – generated mass
H2O target 16ΛN
Comparison with hall A data
