HES-HKS analysis meeting

Toshiyuki Gogami10Jan2014

Contents

• About missing mass resolution• Blind analysis• Resolution and linearity balance• Response function

• Missing mass status• Binding energy and cross section• 12

ΛB, 10ΛBe and 7

ΛHe

Missing mass estimation by the full-modeled Monte Carlo simulation

Achievable resolutionHyperon Hypernucleus

Target [mg/cm2]

Intrinsic Mass offset due to energy loss

Matrix z-dependence (B)

Simulated total resolution (A)

Achievable resolution (A-B)

Present work(Toshi’s anlysis)

Λ CH2 (450) 830 1000 730 2100 1380 16007

ΛHe 7Li (184.0) 440 260 550 1300 750 13009

ΛLi 9Be(188.1) 440 260 170 740 560 Not yet10

ΛBe 10B (56.1) 430 80 40 590 550 80012

ΛB 12C (87.5) 430 130 80 620 540 89052

ΛV 52Cr (134.0) 430 160 30 630 600 Not yet

Part of the z-dependence (Λ, Σ0 and 12ΛB) is absorbed by the matrices in a matrix tuning.

Effects of z-dependence absorption for other hypernuclei are not trivial. Blind analysis

( FWHM, Unit: keV )

Blind analysis

• Width and linearity balance• Matrix z-dependence (Λ,Σ0) absorption effect for hypernuclei

• Response function

Flow chartInitial matrices(not distorted)

Tuned matrices

Tune

Λ, Σ0 and hypernucei

Λ, Σ0 and hypernuceiAbsorbing effects of • z-dependence• Asymmetry shape• Etc.

Compare after tuningΛ + B.G.Σ0 + B.G.12

ΛB s-shell

Generated

Results

FWHM

[keV

]

ΔMM

[keV

]

Mean value displacement Width

Λ, Σ0, 12ΛB

Λ, Σ0

Λ, Σ0, 12ΛBΛ, Σ0

ΔMM < 130 keV 500 ~ 700 keV (12ΛB, 10

ΛB, 52ΛV)

~ 1000 keV (7ΛHe)

~ 1500 keV (Λ, Σ0) Achieved simultaneously !

Λ + B.G.Σ0 + B.G.12

ΛB s-shellNo matrix distortion+

Achievable resolutions

Response function

Missing mass status

12C(e,e’K+)12ΛB

7Li(e,e’K+)7ΛHe

10B(e,e’K+)10ΛBe

9Be(e,e’K+)9ΛLi

52Cr(e,e’K+)52ΛV

12C(e,e’K+)12ΛB

7Li(e,e’K+)7ΛHe

10B(e,e’K+)10ΛBe

9Be(e,e’K+)9ΛLi

Accidental background

52Cr(e,e’K+)52ΛV

Binding energy and Cross section• About cross section• Definition• Cut conditions• Efficiencies and correction factors

• Results• 12C(γ*,K+)12

ΛB• 7Li(γ*,K+)7

ΛHe• 10B(γ*,K+)10

ΛBe

Definition of differential cross section

Number of virtual photonincluding HES acceptance

Number of target protons EfficienciesHKS acceptance

Cut conditions

• 0.80 < pe < 0.98 [GeV/c]

• Abs(m2-m2K) < 0.3

• -1.0 < ctime < 1.0

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 large energy loss (not included for the present work)

• Already studied by Fujita ~ 5- 10%

12C target

RemarksEfficiencies are different

between low and high current data

Two set of HES collimator positions are used.

Differential cross section of 12C(γ*,K+)12

ΛB

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 )

12ΛB comparison

Experiment -BΛ [MeV] Cross section [nb/sr]

E05-115 -11.40 ± 0.03 83 ± 3

E01-011 -11.40 ± 0.01 ± 0.04 101 ± 4.2 (+ 38 – 31)

E89-009 -11.52 ± 0.35 140 ± 17 ± 18

Emulsion -11.37 ± 0.06 N/A

SΛ

Experiment -BΛ [MeV] Cross section [nb/sr]

E05-115 -0.38 ± 0.04 82 ± 3

E01-011 -0.41 ± 0.01 ± 0.13 94 ± 4.0 ±35

E89-009 -0.49 ± 0.16 N/A

pΛ

7Li targetRemarksTarget thickness (Three values)

Shichijo: 184.0 mg/cm2

ELOGWeight and area: 331.2 mg/cm2

Oil ? Nitriding ? Thickness and density: 207 mg/cm2

• Nitriding test• Check Brems. Rate in HES• Etc.

Need to be done !!!!

Differential cross section of 7Li(γ*,K+)7

ΛHe

Peak -B [MeV] Number of event

Cross section [nb/sr]

1 -5.28 ± 0.14 482±22 12.4 ±0.5

2 -3.50 ± 0.14 271±16 7.0 ±0.4

( FWHM ~ 1.3 MeV )

7ΛHe comparison

(FWHM ~ 1.3 MeV) -5.36 without CSB-5.16 with CSB

Peak -B [MeV] Number of event

Cross section [nb/sr]

1 -5.28 ± 0.14 482±22 12.4 ±0.5

2 -3.50 ± 0.14 271±16 7.0 ±0.4

( FWHM ~ 1.3 MeV )

Hiyama’s calc.

10B target

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 )

Comparison with old data

MeV

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.

9Be(γ*,K+)9ΛLi (only figure)

Summary

• Estimated missing mass resolution• Blind analysis• Resolution and linearity balance• Response function

• Missing mass status• Binding energy and cross section• 12

ΛB, 10ΛBe and 7

ΛHe

Backup

Expected achievable missing mass resolution•分解能の表• 各寄与• Z-depenenceを引いた後に残る分解能

Tuningで z-dependenceを吸収 Resolution ? Linearity?

Blind analysis (next)