HLAB meeting

117
HLAB meeting Status Report Toshi Gogami 1/Nov/2011 JLab E05-115 collaboration, 2009, JLab Hall-C

description

HLAB meeting. Status Report Toshi Gogami 1/Nov/2011. JLab E05-115 collaboration, 2009, JLab Hall-C. Contents. ( e,e’K + ) experiments in JLab & Mainz. JLab E05-115 (2009) The number of events for high multiplicity data. JLab & Mainz. e + p ➝ e’ + K + + Λ. - PowerPoint PPT Presentation

Transcript of HLAB meeting

Page 1: HLAB meeting

HLAB meetingStatus ReportToshi Gogami 1/Nov/2011

JLab E05-115 collaboration, 2009, JLab Hall-C

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Contents

• (e,e’K+) experiments in JLab & Mainz.• JLab E05-115 (2009)

– The number of events for high multiplicity data

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JLab & Mainze + p ➝ e’ + K+ + Λ

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Spectroscopic experiment by (e,e’K+) reaction

pn

γ*

ΛK+

e-

e + p ➝ e’ + K+ + Λe e

target nucleus

Feynman diagram

uud

ussud

–p K+

Λ

γ*

e’-Spectrometer

K+-Spectrometer

pe’

pK+

Coincidence Missing Mass HHY

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Experimental setup of JLab E05-115

Splitter Magnet

HKS

HES e’

K+

p(e,e’K+)Λ,(Σ0)

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Experimental setup of JLab E05-115

2×10-4

7 [msr]3 – 12 [deg] 2×10-4

8.5 [msr]2 – 12 [deg]

7Li , 9Be , 10B , 12C , 52Cr

p(e,e’K+)Λ

( 7ΛHe , 9

ΛLi , 10ΛBe , 12

ΛB , 52ΛV ) 2 - 50 [μA]

10 - 300 [THz]

Tracking

Data taking : Aug-Nov 2009

CH2, H2O

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Discrepancy of Number of Λ

Lost events that we are interested in in tracking procedure.ECT*/JSPS core to core, T.Gogami (2011) 7

Black : hit wires Blue : selected wiresRed : track

Black : hit wires Blue : selected wiresRed : track

REAL DATA REAL DATA

Λ Λ

Σ0Σ0

CH2 Target H2O Target

The number of ΛNΛ ¼ Nexpect

12C quasi-free

Acc. b.g.

16O quasi-freeAcc. b.g.

The number of ΛNΛ Nexpect

Very preliminary

Very preliminary

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New tracking code

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Results of Introduction of new Tracking Code

Increased !

Increased !

CH2

52Cr

•NΛ ¼ Nexpect

NΛ ½ NexpectH2O

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For further improvement

• Efficiency– Tracking– TOF detectors

• Discarded events

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Rates of the KDC wires52Cr, 77124

Wire Number

Rate

[kHz

]KDC1-u KDC1-u’ KDC1-x KDC1-x’ KDC1-v KDC1-v’

KDC2-u KDC2-u’ KDC2-x KDC2-x’ KDC2-v KDC2-v’

< 510 kHz < 350 kHz

< 290 kHz < 230 kHz

52Cr, 77124

KDC1 KDC2~11 MHz~22 MHz

77124 ( 52Cr target )

5 × 5

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Rates of the HKS TOF detectors

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Events which are discarded

52Cr, 77124

KDC1

KDC2

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Events which are discarded

52Cr, 77124

KDC1

KDC2

• Where and why are these events discarded ?• Are these events threw away by correct cut condition?

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Summary

• Need to improve analysis code for high multiplicity data– Efficiencies– Rescue discarded events

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END

JLab Hall-C circuit room, 5/Nov/2009

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Backup

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Decay Pion Spectroscopy to Study -Hypernuclei

12C -

Weak mesonic two body decay

1- 0.02- ~150 keV

Ground state doublet of 12

BB and

Direct Production

p

e’

e12C K

+

Example:

Hypernuclear States:s (or p) coupled to low lying core nucleus

12Bg.s.

E.M.

*

12B

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Decay Pion Spectroscopy for Light and Exotic -Hypernuclei

Fragmentation Process

p

e’

e 12C

Example: K +

*

s12B*

Highly Excited Hypernuclear States:s coupled to High-Lying core nucleus, i.e.particle hole at s orbit

4H

Fragmentation (<10-16s)

4Hg.s.

4He

-

Weak mesonic two body decay (~10-10s)

Access to variety of light and exotic hypernuclei,

some of which cannot be produced or measured

precisely by other means

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Spectroscopic experiment by (e,e’K+) reaction

pn

γ*

ΛK+

e-

e + p ➝ e’ + K+ + Λe e

target nucleus

Feynman diagram

uud

ussud

–p K+

Λ

γ*

1. Large Momentum transfer• Λ can be bounded in deeper orbit

2. Λ’s spin at forward angle• Spin flip ~ spin non-flip

3. Proton Λ,Σ0

• Absolute mass scale calibration

e’-Spectrometer

K+-Spectrometer

pe’

pK+

Coincidence Missing Mass HHY

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JLab E05-115 experimental setup

2×10-4

7 [msr]3 – 12 [deg]

2×10-4

8.5 [msr]2 – 12 [deg]

e + p → e’ + Λ + K+

7Li , 9Be , 10B , 12C , 52Cr

• (e,e’K+) experiment 1. Coincidence experiment (K+ and e-)2. Small cross section ( ~100 [nb/sr] ) 1/10003. Energy resolution Sub MeV (FWHM)

Primary beam• High intensity

Thin target (~100 [mg/cm2])• High quality

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Experimental setup of JLab E05-115

2×10-4

7 [msr]3 – 12 [deg] 2×10-4

8.5 [msr]2 – 12 [deg]

7Li , 9Be , 10B , 12C , 52Cr

p(e,e’K+)Λ

( 7ΛHe , 9

ΛLi , 10ΛBe , 12

ΛB , 52ΛV ) 2 - 50 [μA]

10 - 300 [THz]

Tracking

Data taking : Aug-Nov 2009

HKS chamber wire configuration

CH2, H2O

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HKS Drift Chamber hit selectionwith TOF detectors

• GREEN regionSelective region

• RED markersSelected hit wires

• BLACK markersRejected hit wires

Particle direction

Gravity

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Results of Introduction of new Tracking Code

Increased !

Increased !

CH2

52Cr

•NΛ ¼ Nexpect

NΛ ½ NexpectH2O

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Theoretical calculation of A=7 system

-B (MeV)

-6.650.03 0.2 MeV from α n n

JLab E01-0117Li(e,e’K+)7

ΛHe

Four-body cluster model for T=1 triplet hypernuclei(E.Hiyama et al., NPC 80, 2009)α + Λ + N + N

CSB interaction is determined to reproduce BΛ of 4

ΛH and 4ΛHe.

Preliminary

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(e,e’K+) experiment in JLab Hall-C2000

1st generation exp. JLab E89-009ENGE(e’) + SOS(K+)

12ΛB

~ 750 [keV] (FWHM)

2005 2nd generation exp. JLab E01-011ENGE(e’) + HKS(K+) + Tilt method

7ΛHe,12

ΛB,28ΛAl

~ 500 [keV] (FWHM)

2009 3rd generation exp. JLab E05-115HES(e’) + HKS(K+) + Tilt method

7ΛHe,9

ΛLi,10ΛBe, 12

ΛB,52ΛV

≤ 500 [keV] (FWHM)

Proof of feasibility

Establish exp. method

Up to Medium heavy

12C(e,e’K+)12ΛB

E89-009

Preliminary

sΛpΛ

~750 [keV] (FWHM)

Confirming stage

Analysis stage

sΛpΛ dΛ

28Si(e,e’K+)28ΛAl

E01-011

~600 [keV] (FWHM)

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(e,e’K+) experiment in JLab Hall-A

2007 JLab E94-107

HRS’s (K+, e+)+ septum9

ΛLi,12ΛB,16

ΛN~ 670 [keV] (FWHM) 16O(e,e’K+)16

ΛN

12C(e,e’K+)12ΛB

sΛ pΛ

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HES のバックグラウンド• ハイパー核生成に関係した電子 赤• HES 側のバックグラウンド

– 制動放射起因の電子 緑– Møller 散乱起因の電子 青

モンテカルロシミュレーションでそれぞれ 150000 イベント生成させた  バックグラウンドである、 0o 方向に集中する Møller 散乱・制動放射起因電子を避ける Tilt 法を導入

Tilt 法の概略図   第一世代      第二世代   200 [MHz]        1 [MHz]  

e’ rateAPFB2011 in Korea (T.Gogami) 28

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Tilt 角の最適化• ハイパー核生成に関与した電子の計数率 S• Mφller 散乱起因電子の計数率 NMφller

• 制動放射起因電子の計数率 NBrems

Figure of Merit (FoM)

Target e’ rate [kHz]10B 48012C 55852Cr 1780

6.5o

ビーム強度 30 [μA] , 100 [mg/cm2] を仮定

シミュレーションによる計数率の見積もり

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角度アクセプタンス

ハイパー核の収量が増加

第二世代実験 E01-011

第三世代実験 E05-115

入射電子ビームのエネルギー1.851 2.344 [GeV]

•HES の角度アクセプタンスが広い

•バックグラウンドがより前方に集中 アクセプタンスをより前方へ

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運動量アクセプタンス Ei=2.344,ω=1.5[GeV]

測定するハイパー核の生成領域を広くカバーするように設計した。

立体角• 一様に生成した全粒子の数を NGen

• 一様に生成した全粒子の立体角を ΔΩGen

• HES の最下流まで通過した粒子の数を Npass

立体角 ~6.5[msr] w/ splitter

HKS と HES の運度量の相関

52ΛV g.s.

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89Y(π+,K+)89ΛY, 51V(π+,K+)51

ΛV

89Y(π+,K+)89ΛY 51V(π+,K+)51

ΛV 12C(π+,K+)12ΛC

1.45 [MeV] (FWHM)KEK-PS E36989Y(π+,K+)89

ΛYKEK-PS E36951V(π+,K+)51

ΛV KEK-PS E36912C(π+,K+)12

ΛC

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E05-115 experimental motivation(2)

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s

p d f

Photo- and electro production of medium mass Λ-hypernuclei ,P.Bydzovsky et al. (2008)

FULL(8)1f7/2

1d3/2FULL(4) FULL(4)・・・・・・sn = 28 p = 24p

d

f

4-

5+

6-

7+

3-

4+

5-

6+

Λ52ΛV

52Cr

or

or

or

or

ls splitting 2l+1∝

• ls splitting • Core excited

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Spectroscopic experiment via (e,e’K+) reaction

pn

γ*

ΛK+

e-

e + p ➝ e’ + K+ + Λe e

M2HY = (Ee + MT - EK+ - Ee’)2 - ( pe - pK+ - pe’)2

measuretarget nucleus

Feynman diagram

uud

ussud

–p K+

Λ

γ*

Missing mass :

•Binding energy•Cross section

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P.Bydzovsdy ,photo- and electro production of medium mass Λ-hypernuclei, 2008

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Λ single particle energy

D.J.Millener et al. PRC 38, 6, 1988Woods-Saxson potential with a depth of 28 [MeV] and a radius parameter

(e,e’K+) experiments in JLab• E89-009 (2000)• E94-107 (2004)• E01-011 (2005)• E05-115 (2009)

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Feature of (e,e’K+) reaction

uud

ussud

e e

–p K+

Λ

γ*

ud

ddu

us

sdu

– –π+

Λn

us

ddu

ud

sdu

–K-

Λn

–π-

e + p ➝ e + K+ + Λ π+ + n ➝ K+ + Λ

K+

K- + n ➝ π- + Λ(π+ , K+) (K- , π-)(e,e’K+)

Momentum transfer(Typical )

~300 [MeV/c] ~300 [MeV/c] ~90 [MeV/c]

Λ’s SpinAt forward angle

Λ’s from proton neutron neutron

flip ≈ non-flip non-flip non-flip

Beam primary secondary secondary

Target Thin (~100 mg/cm2)(Isotopically enriched) Thick(> a few [g/cm2] ) Thick(> a few [g/cm2] )

Reaction

Λ can be bounded in deeper orbit

Spin dependent structure

Mirror lambda hypernuclei

High quality , high intensity

Fine structureEnergy resolution

(FWHM)≤ 500 [keV] 1 – 3 [MeV] 1 – 3 [MeV]APFB2011 in Korea (T.Gogami) 37

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Theoretical calculation of A=7 system

-B (MeV)

-6.650.03 0.2 MeV from α n n

JLab E01-0117Li(e,e’K+)7

ΛHe

Four-body cluster model for T=1 triplet hypernuclei(E.Hiyama et al., NPC 80, 2009)α + Λ + N + N

CSB interaction is determined to reproduce BΛ of 4

ΛH and 4ΛHe.

Preliminary

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(e,e’K+) experiment in JLab Hall-C2000

1st generation exp. JLab E89-009ENGE(e’) + SOS(K+)

12ΛB

~ 750 [keV] (FWHM)

2005 2nd generation exp. JLab E01-011ENGE(e’) + HKS(K+) + Tilt method

7ΛHe,12

ΛB,28ΛAl

~ 500 [keV] (FWHM)

2009 3rd generation exp. JLab E05-115HES(e’) + HKS(K+) + Tilt method

7ΛHe,9

ΛLi,10ΛBe, 12

ΛB,52ΛV

≤ 500 [keV] (FWHM)

Proof of feasibility

Establish exp. method

Up to Medium heavy

12C(e,e’K+)12ΛB

E89-009

Preliminary

sΛpΛ

~750 [keV] (FWHM)

Confirming stage

Analysis stage

sΛpΛ dΛ

28Si(e,e’K+)28ΛAl

E01-011

~600 [keV] (FWHM)

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(e,e’K+) experiment in JLab Hall-A

2007 JLab E94-107

HRS’s (K+, e+)+ septum9

ΛLi,12ΛB,16

ΛN~ 670 [keV] (FWHM) 16O(e,e’K+)16

ΛN

12C(e,e’K+)12ΛB

sΛ pΛ

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Elementary process p(e,e’K+)Λ

• p(e,e’K+)Λ,Σ0 are used for Energy calibration

• Study of elementary process

• Consistency check with past experiment

~40 hours(5 shifts)

JLab E05-115p(e,e’K+)Λ,Σ0

Very preliminary

R. Bradford et al. , FRC73, 2006APFB2011 in Korea (T.Gogami) 41

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Single Λ hypernuclear spectroscopy• (π+,K+), (K+,π+) spectroscopy

– CERN, BNL, KEK• A = 7 – 208• Resolution (FWHM) ~ a few MeV

• γ-ray spectroscopy with Ge detector– KEK, J-PARC

• A=7 – 16• Resolution (FWHM) ~ a few keV

• Decay pion spectroscopy– Mainz Univ.

• A < 10• Resolution (FWHM) < 100 keV

• (e,e’K+) spectroscopy– JLab, (Mainz Univ.)

• A=7 – 52• Resolution (FWHM) ~ 500 keV

Determine Absolute value

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(e,e’K+) reaction

uud

ussud

e e

–p K+

Λ

γ*

ud

ddu

us

sdu

– –π+

Λn

us

ddu

ud

sdu

–K-

Λn

–π-

e + p ➝ e + K+ + Λ π+ + n ➝ K+ + Λ

K+

K- + n ➝ π- + Λ(π+ , K+) (K- , π-)(e,e’K+)

Momentum transfer(Typical )

~300 [MeV/c] ~300 [MeV/c] ~90 [MeV/c]

Λ’s SpinAt forward angle

Λ’s from proton neutron neutron

flip ≈ non-flip non-flip non-flip

Beam primary secondary secondary

Target Thin (~100 mg/cm2)(Isotopically enriched) Thick(> a few [g/cm2] ) Thick(> a few [g/cm2] )

Reaction

Λ can be bounded in deeper orbit

Spin dependent structure

Mirror lambda hypernuclei

High quality , high intensity

Fine structureEnergy resolution

(FWHM)≤ 500 [keV] 1 – 3 [MeV] 1 – 3 [MeV]APFB2011 in Korea (T.Gogami) 43

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JLab CEBAF ( Continuance Electron Beam Accelerator Facility )

• (e,e’K+) experiment1. Coincidence experiment (K+ and e-)2. Small cross section ( ~100 [nb/sr] ) 1/10003. Energy resolution sub MeV (FWHM)

100 [m]

Maximum beam energy 6.0[GeV]

Maximum beam intensity 200[μA/Hall]

Beam emittance ~2 [mm ・ μrad]Beam energy spread <1×10-4

Beam bunch interval ~2[ns] (499[MHz])

• Requirement for accelerator1. high duty factor2. high intensity3. small emittance small ΔE/E

CEBAF can satisfythese requirements

Thomas Jefferson National Accelerator Facility

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(e,e’K+) experiment in JLab Hall-C2000 年

1st generation exp. JLab E89-009ENGE(e’) + SOS(K+)

12ΛB

~ 900 [keV] (FWHM)

2005 年 2nd generation exp. JLab E01-011ENGE(e’) + HKS(K+) + Tilt method

7ΛHe,12

ΛB,28ΛAl

~ 500 [keV] (FWHM)

2009 年 3rd generation exp. JLab E05-115HES(e’) + HKS(K+) + Tilt method

7ΛHe,9

ΛLi,10ΛBe, 12

ΛB,52ΛV

≤ 500 [keV] (FWHM)

Luminosity ×137e’ rate 1/200S/N ×2.7

Proof of feasibility

Establish exp. method

Medium heavy

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JLab E05-115 experiment

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E05-115 experimental motivation (1)

• p-shell(7He , 9Li , 10Be , 12B) Charge symmetry breaking

(CSB) ΛN-ΣN coupling

•2009 Aug – Nov @ JLab Hall-C•(e,e’K+) reaction•Target : 7Li , 9Be , 10B , 12C , 52Cr

Λ Λ Λ Λ

First try

B Λ [M

eV]

It is difficult experimentally.“ b.g. electron due to brems. ~Z∝ 2 “

A = 52

• Medium heavy (52V) s-,p-,d-,f-orbit binding energy & cross section Mass dependence of Λ single

particle energy l ・ s splitting , core configuration

mixing dΛ, fΛ –state

Λ

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JLab E05-115 experimental setup

2×10-4

7 [msr]3 – 12 [deg] 2×10-4

11 [msr]2 – 12 [deg]

e + p → e’ + Λ + K+

7Li , 9Be , 10B , 12C , 52Cr

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JLab E05-115 experimental setup

2×10-4

7 [msr]3 – 12 [deg] 2×10-4

11 [msr]2 – 12 [deg]

e + p → e’ + Λ + K+

7Li , 9Be , 10B , 12C , 52Cr

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HKS detectors

K+

p, π+

Drift chambers-KDC1,KDC2-TOF walls -2X,1Y,1X-

(Plastic scintillators)

Cherenkov detectors -AC,WC-• Aerogel (n=1.05)• Water (n=1.33)

1 [m] June 2009 in JLab Hall-C

HKS trigger• CP = 1X ×1Y × 2X • K = WC × AC

CP × K

~18 [kHz](8 [μA] on 52Cr)

−π+

K+

p

σ ≈ 200 [μm]TOF σ ≈ 170 [ps]APFB2011 in Korea (T.Gogami) 50

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HES DetectorsDrift chambers- EDC1 , EDC2 -

TOF walls - EH1 , EH2 - (Plastic scintillators)

HES D magnet

HES triggerEH1 × EH2

~2 [MHz](8 [μA] on 52Cr)e

Time Of Flight

σ ~ 300 [ps]

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Data Summary

JLab E05-115 (2009/June – 2009/Nov)

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Analysis process

trackingx , x’ , y , y’ at Reference plane

x’ , y’ , pat Target

Missing Mass

trackingx , x’ , y , y’ at Reference plane

x’ , y’ , pat Target

p : Λ , Σ0 ,12ΛB

Angle : Sieve slit

F2T functionF2T function

particle ID(select K+)

HKSHES

tune tune

This talk

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Λ and Σ0

Because of high multiplicity of HKS(analysis code cannot handle with high multiplicity)

~40 hours(5 shifts)

p(γ*,K+)Λ,Σ0

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Analysis for high multiplicity data

KDC1

KDC2

HKS event displayAPFB2011 in Korea (T.Gogami) 55

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Background event of HKS

HKS dipole magnet

NMR port

z [cm]

y [cm]

x [cm] KDC1

KDC2

KDC1

KDC2

9Be , 38.4 [μA]Overhead view

Background events

Events on HKS optics

Β ≈ 1e- , e+

SIMULATIONAPFB2011 in Korea (T.Gogami) 56

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Singles rate summaryUp to ~30 [MHz]

Up to ~15 [MHz]HES

HKS

HKS trigger ~ 10[kHz]

HES trigger ~ a few[MHz]

COIN 2.0 [kHz]

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Multiplicity of typical layer of chamberHES HKS

~1.13

~1.28

~2.24

~4.94

Multiplicity is high for HKS

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HKS drift chamber wire configuration

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Hit wires in KDC1

Overhead viewKDC1

Black : hit wires Blue : selected wiresRed : track

Black : hit wires Blue : selected wiresRed : track

CH2 52Cr

Misidentification chance in hit wires selection increase !

REAL DATA REAL DATA

low high low high

Overhead view

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New tracking scheme

Good TDC

Pattern recognition

Track fit

Solve left right

Select good combination

Combination selection with TOF counters

Reduce hit wire combinations (h_tof_pre.f)

High multiplicity

• Hit wire selection with TOF• 1X & 2X • Grouping

• Pre-PID• Cherenkov detectors

Reduce hit wires to analyze

NEW

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DC hit info. selection with TOF

Selective region Maximum gradient

Minimum gradient

Particle direction

Gravity

CUT~8%

~17%

Procedure in “h_dc_tofcut.f”1. Get KTOF1X & 2X hit counter information2. Make combination of 1X and 2X hit counter if those two are in

same group (grouping) 3. Determine cut conditions on KDC1 & KDC24. Select Hit wires in KDC and Reorder them

CUT

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Hit wires event display (1)

• GREEN regionSelective region

• RED markersSelected hit wires

• BLACK markersRejected hit wires

Seems to work well

Particle direction

Gravity

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Apply to u,v-layer

Applied to uu’ and vv’ layers , too.

Selective region determined by 1X and 2X

Convert

v v’-layer

x x’-layer

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Hit wires event display (2)

• GREEN region Selective region• RED markers & lines Selected hit wires• BLACK markers & lines Rejected hit wires

v v’ u u’

x x’

v v’ u u’

x x’

KDC1 KDC2particle particle

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Results of Introduction new code

Λ c.s. (CH2/H2O) issue is solved

Increased !

Increased !

CH2

52Cr

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Rate dependences

Quadratic dependence Linear dependence

• Why residuals get worse with rate (Multiplicity) ?– Hardware ?– Tracking is worse ?– Parameters ?

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KTOF multiplicity ~2.7 ~1.8

~6.5 ~3.8

CH2 , 76314 52Cr , 77124Multiplicity of KDC are not only high but also TOF counters are! (for heavy target )

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Background event from NMR port

z [cm]

y [cm]

x [cm]

These particles come from NMR port

HKS dipole magnet

NMR port

KDC1

KDC2

KDC1

KDC2

KDC1

KDC2

KDC1

KDC2

Background events

9Be , 38.4 [μA]

9Be , 38.4 [μA] 9Be , 38.4 [μA]

Events on HKS optics

Overhead view

Side view

Β ≈ 1e- , e+

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B.G. mix rate (real data)

ab

B.G mix rate =

* hks ntulpeAPFB2011 in Korea (T.Gogami) 70

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e+ simulation

SIMULATION

• To see 1. Number of event2. Angle & momentum

of e+ generated in target

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Target thickness dependence(Simulation)

H2O52Cr9Be

12C CH2

10B

7Li

Consistent with B.G. mix rate !

SIMULATION

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Angle and momentum distribution of positrons

HKS cannot accept positrons directly !

Generate these event in HKS GEANT(Next page)

SIMULATION

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e , e+ background in GEANT simulation

Vacuum chamber(sus304)

NMR port(sus304)

KDC1 KDC2

e- , e+

• Generated particle : e+

• Distribution : spherical uniform• Momentum : 860 – 1000 [MeV/c]• Angle : 0 – 2 [mrad]• 1000 events

Number of e+ (Simulation) B.G. mix rate (Real data)Correlation

e+ generated in target make HKS dirty

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Basic tracking procedure

Good TDC

Pattern recognition

Track fit

Solve left right

Select good combination

Black : hit wires Blue : selected wiresRed : track

CH2 target

KDC1

52Cr target

Combination selection with TOF counters

Reduce hit wire combinations (h_tof_pre.f)

High multiplicity

Real data

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Results of TOF cut with grouping

CH2 , 2.0 [μA] , 76315

Shift

Same

Residual

Multiplicity

CH2 , 2.0 [μA] , 76315

σ 150 [μm] σ 150 [μm]

~2.3

~1.2

before after

x x’ x x’

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Result of TOF cut with groupingOriginal code

With “h_dc_tofcut.f”Pure Selective regionallowance

allowance

KDC

Too strict

select

Optimal allowance

Good tracks hid by background appear ! Number of K+ ~2[%] up

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Apply to u,v-layer

Applied to uu’ and vv’ layers , too.

Selective region determined by 1X and 2X

Convert

v v’-layer

x x’-layer

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Results of TOF cut with grouping (all layers)

Residual

Multiplicity

CH2 , 2.0 [μA] , 76315

σ 150 [μm] σ 150 [μm]

Multiplicity of uu’vv’-layers• CH2

• ~20% reduction• 52Cr

• ~5-10% reduction

Same

before after

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Results of TOF cut with grouping (all layers)

Faster !

Increase !TOF cut works well

52Cr

CH2

52CrFaster !

Increase !

Parameters ?APFB2011 in Korea (T.Gogami) 80

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Gogami’s study for other targets

Target S (before) S (after) N(before) N (after)12C (20mA) 7812 7840 (+0.4%) 6399 6429 (+0.5%)12C (35mA) 18016 19130 (+6.2%) 35854 38374 (+7.0%)7Li 29009 35771(+23.3%) 55737 72609 (+30.2%)10B 27811 27964(+0.5%) 21236 22000(+3.5%)

52Cr 1206 2958(+145.3%) 4902 11878(+142.3%)

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Coincidence time vs. Mass square

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Cherenkov cut

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Cherenkov light

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p(γ*,K+)Λ/Σ0 cross section

Correction factors : • AC cut ~ 0.89• WC cut ~ 0.94 • HKS tracking ~ 0.99• Mass2 cut ~ 0.99• Kaon decay factor ~ 0.25• (HES tracking ~ 0.9)• EHODO inefficiency• Lambda decrease ~ 0.84

CH2 H2OΛ [nb/sr] 530 ± 50(stat) + 50 (syst) 280 ± 40(stat) + 40 (syst)Σ0 [nb/sr] 120 ± 30(stat) +10 (syst) 70 ± 20(stat) +10 (syst)

Λ/Σ0 ratio 530/120 ~ 4 280/70 = 4

- 20

- 10

-0

- 0

Comparison of CH2 and H2O

Difference between CH2 and H2O

• Coincidence time• HES analysis efficiency• # of virtual photon• Accidental kill by AC• Detectors' cut efficiency

→ Need to estimate these factors precisely

HKS analysis: almost consistent

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After Gogami’s studyDoi CH2 H2O H2O/CH2

Λ 3880 410 0.11Σ0 910 100 0.11

G/K CH2 H2O H2O/CH2

Λ 5113 1002 0.20Σ0 1342 131 0.10

CH2 H2O H2O (expected)

Λ [nb/sr] 530 280 280*0.20/0.11~510

Σ0 [nb/sr] 120 70 70*0.10/0.11~60

Λ/Σ0 ratio 530/120 ~ 4 280/70 = 4

(assume the cross section in CH2 is consistent for both analysis)

←Fitting of S has problem?need more study

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Basic image of matrix tuning procedure1st loop 2nd loop 3rd loop

Tuning w/ , SInitial : G4100 times iteration

Tuning w/ , S, 12Bgs

Initial : Result of 1st loop100 times iteration

Tuning w/ , S, 12Bgs

Initial : Result of 2st loop100 times iteration

Obtain 100 12B

(20uA run) spectrums-> Fit the 100 gs peaks with gaussian-> Select the finest peak

Obtain 100 12B

(35uA run) spectrums-> Fit the 100 gs peaks with gaussian-> Select the finest peak

Obtain 100 12B

(35uA run) spectrums-> Fit the 100 gs peaks with gaussian-> Select the finest peak

・・・ ・ ・ ・・・・・・・・・・ ・ ・ ・・・ ・・

・・・ ・ ・ ・・・

Use as next initial Use as next initial

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In the loop

select peak(, S0, 12

Bgs)

Mimimize c2

obtain new matrices

calculate MM

Initial matrices

iterate n times

New matrices(n sets)

How to select peaks?• How to decide the cut region? 1s? 2s?• How about the fitting?

How to decide the c2?• weight• asymmetric c2?

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SS tune before/after (HKS)Column, before Column, after

Row, before Row, after

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The effect of SS tune (HKS)y’ vs x’ (before tune)

y’ vs x’ (after tune)

yss vs xss (before tune)

yss vs xss (after tune)

Need more tune?

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第一世代実験 E89-009 ( 2000年)• スペクトロメータの構成 splitter+SOS+Enge• 測定した主なハイパー核 12

ΛB• エネルギー分解能 ~750[keV](FWHM)     (当時最高 )

(e,e‘K+) 反応を用いたハイパー核分光実験が可能であることを証明した APFB2011 in Korea (T.Gogami) 91

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• スペクトロメータの構成 splitter+Enge+HKS• 測定した主なハイパー核 7

ΛHe,12ΛB,28

ΛAl• エネルギー分解能 ~400[keV](FWHM)

HKS 建設エネルギー分解能向上Tilt 法の導入 S/N を劇的に改善

第二世代実験 E01-011(2005年 )

技術の確立 APFB2011 in Korea (T.Gogami) 92

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Expected Missing mass of 52ΛV

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Typical Trigger Rate

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バックグラウンドを含める ??

target current Kaon Pion Proton

  [μA] [Hz] [kHz] [kHz]

CH2 2.0 82.3 6.7 7.1 7Li 31.6 325 27.2 37.1

9Be 37.9 269 23.4 31.7 10B 38.2 152 11.8 15.0 12C 19.3 125 9.1 11.1

52Cr 7.3 34.2 4.6 3.4

HKS Rate summary

Page 97: HLAB meeting

Target hypernucleus thickness[mg/cm2]

beam current[μA]

total charge[C]

number of QF Λ (online)

expected number of

g.s.7Li 7He 184.0 32.0 4.84 6.4E+4

(1.0 μb/sr)~1000

(20 nb/sr)9Be 9Li 188.1 38.3 5.33 4.5E+4

(1.2 μb/sr)~200

(5 nb/sr)10B 10Be 56.1 38.7 6.25 4.8E+4

(1.3 μb/sr)~800

(20 nb/sr)12C 12B 112.5 26.8 5.90 3.4E+4

(1.5 μb/sr)~2000

(100 nb/sr)52Cr 52V 134.0

154.07.6 0.83

5.538.0E+3

(4.7 μb/sr)~100

(70 nb/sr)

Data summary

APFB2011 in Korea (T.Gogami)

Λ

Λ

Λ

Λ

Λ

E05-115 ( 2009 Aug – Nov )

measuredassumption

Target hypernucleus thickness[mg/cm2]

beam current[μA]

total charge[C]

CH2 Λ , Σ0 450.8 2.0 0.28

H2O Λ , Σ0 ~500.0 2.7 0.20

Physics Data

Calibration Data

97

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E01-011

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and S spectra (CH2 target)

c.f. E89-009, 183 hours (8.8 mg/cm2, 0.5 or 1.0 uA)T. Miyoshi et al., Phy. Rev. Lett. 90, 232502(2003)

Better resolution and statistics

~ 3.5 MeV (FWHM)

1.9 MeV (FWHM) S

2.3 MeV (FWHM)

E01-011 ~70 hours (450 mg/cm2, 1.5 uA)

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Background subtraction

Accidental background : polynomial functionAPFB2011 in Korea (T.Gogami) 100

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GEANT412C 100 mg/cm2

Effect of simple gaussian fit:D= +20 keV

count difference : -30 %

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12C(e,e’K+)12B

Resolution : ~470 keV (FWHM) for g.s.Data taking : ~30 hours w/ 30 mA

Fitting Result

#1 #2

Two major peaks#1 : [(p3/2)-1

p,(s1/2)]#2 : [(p3/2)-1

p,(p3/2,p1/2)]

(126)(130)

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#1 #2

12C(e,e’K+)12B, 12C(+,K+)12

C

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12C(e,e’K+)12B

#1 #2

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12C(e,e’K+)12B

Red : calculation with SLAGreen : calculation with KMAID

Theory by Sotona et. al. (1.3 < E < 1.6 GeV, 1 < qK < 13 deg.)

Result

#1J Ex

[MeV]Cross section [nb/sr]

SLA KMAID

1-

2-

00.14

19.765.7

20.743.0

2+

3+

10.9911.06

48.375.3

38.068.5

#2

ID Ex [MeV]

Cross section [nb/sr]

Cross section (Calc., SLA) [nb/sr]

#1 0 97±3.9 (stat.) +29,-22 (sys.)

85.4(1- + 2-)

#2 11.18±0.01 (stat.) ±0.10 (sys.)

100±3.8 (stat.) +30, -30 (sys.)

123.6(2+ + 3+)

(126)

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12C(e,e’K+)12B

• Two major peaks ; #1:[(p3/2)-1p,(s1/2)],

#2:[(p3/2)-1p,(p3/2,p1/2)]

– Consistent -B with previous exp.– Different width for g.s. with E94-107 data– Ex and cross sections : agree with shell model

calculation• Best resolution of 470 keV (FWHM) for g.s.

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28Si(e,e’K+)28Al

Resolution : ~450 keV (FWHM) for g.s.Data taking : ~30 hours w/ 30 mA

#1 #2#3

Fitting Result

Three major peaks#1 : [(d5/2)-1

p,(s1/2)]#2 : [(d5/2)-1

p,(p3/2,p1/2)]#3 : [(d5/2)-1

p,(d5/2,d3/2)]

First sd-shell hypernuclear spectroscopy by (e,e’K+)

(78)(122)(77)APFB2011 in Korea (T.Gogami) 107

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Shell model calculation

Full space (0d5/20d3/21s1/2)pn

11,12

DWIAYNG interaction

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#1 #2 #3

28Si(e,e’K+)28Al, 28Si(+,K+)28

Si

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28Si(e,e’K+)28Al

Theory by Sotona et. al. (1.3 < E < 1.6 GeV, 1 < qK < 13 deg.)#1J Ex

[MeV]Cross section [nb/sr]

SLA KMAID

2+,3+ 0 92.1 71.76

4-

3-

9.429.67

134.991.3

117.558.5

4+

5+

17.617.9

148.4139.1

135.189.9

#2#3

ID Ex [MeV]

Cross section [nb/sr] Cross section (Calc. SLA) )[nb/sr]

#1 0 60±5.0 (stat.) +27, -18 (sys.)

92.1(2+ + 3+)

#2 10.98±0.02 (stat.) ±0.30 (sys.)

94±6.0 (stat.) +43, -28 (sys.)

226.2(4- + 3-)

#3 19.30±0.03 (stat.) ±0.30 (sys.)

59±6.7 (stat.) +55, -18(sys.)

287.5(4+ + 5+)

Red : calculation with SLAGreen : calculation with KMAID

Result

(78)

(122)

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28Si(e,e’K+)28Al

• First sd-shell hypernuclear spectroscopy by (e,e’K+)• Three major peaks ; #1:[(d5/2)-1

p,(s1/2)], #2:[(d5/2)-1

p,(p3/2,p1/2)] #3:[(d5/2)-1

p,(d5/2,d3/2)]– Deeper -B for g.s. than 28

Si and shell model calculation– Wider energy spacing between #1 and #2 than calc.– Narrower energy spacing between #2 and #3 than calc.– Smaller cross sections than calc.

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7Li(e,e’K+)7He

#1

Observation of 7He w/ good statistics

Fitting Result (40)APFB2011 in Korea (T.Gogami) 112

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-B= -5.36 w/o CSB -5.16 w/ CSB

CSB effect by cluster modelFour-body cluster model

E.Hiyama et al.PRC80,054321(2009)

NN

Phenomenological potential

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7Li(e,e’K+)7He

J -B [MeV]

Cross section [nb/sr]

SLA KMAID

1/2+ -5.36 13.2 9.7

Theory by Sotona et. al. (Cross section) by Hiyama et. al. ( -B : w/o CSB)(1.3 < E < 1.6 GeV, 1 < qK < 13 deg.)

Result

#1

ID -B

[MeV]Cross section

[nb/sr]

#1 -5.71±0.02 (stat.) ±0.20 (sys.)

31±2.8 (stat.) +11.8,-9.3 (sys.)

Red : calculation with SLAGreen : calculation with KMAID

(40)

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7Li(e,e’K+)7He

• High statistics spectroscopy• -B=-5.71±0.02 (stat.)±0.20 (sys.) for g.s.

– Cluster model calculation-B=-5.36 (w/o CSB)-B=-5.16 (w/ CSB)

• Cross section : larger than shell model calc.

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E01-011 ~Count, S/N~Peak ID # of peak

[counts]# of BG(3s)

[counts]S/N Sys. Err.

(Contami. -%)Sys. Err.

(Loss +%)7He:#1 120 230 0.52 30 30

12B:#1 630 561 1.12 5 30

12B:#2 695 706 0.98 20 30

28Al:#1 145 360 0.40 40 30

28Al:#2 240 516 0.47 40 30

28Al:#3 77 545 0.14 90 30

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