Lambd a hypernuclear spectroscopy up to medium heavy mass number at JLab Hall-C

Lambda hypernuclear spectroscopy up to medium heavy mass number at JLab Hall-C

Graduate school of Science, Tohoku Univ.Toshiyuki Gogami

Contents

• Introduction• Experimental setup• Analyses• Missing mass• Summary

Contents

• Introduction• Experimental setup• Analyses• Missing mass• Summary e e

uud

ussud

–pK+

Λ

γ*

(e,e’K+) reaction

Λ hypernuclear spectroscopy

Updated from: O. Hashimoto and H. Tamura, Prog. Part. Nucl. Phys. 57 (2006) 564.

52LV

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

p

n

γ*

ΛK+

e-

e + p ➝ e’ + K+ + Λ

target nucleus

~ 1990’s The (K-,π-) , (π+,K+) reactions• Energy resolution ~ a few MeV• n Λ

e’-Spectrometer

K+-Spectrometer

pe’

pK+

Coincidence Missing Mass MHY

2000~The (e,e’K+) reaction• Energy resolution ~0.5 MeV• p Λ

Experimental motivation• JLab E05-115 (2009, Hall-C)– Elementary processes (Λ,Σ0)– 7

ΛHe[1], 9ΛLi, 10

ΛBe• ΛN charge symmetry breaking• ΛN-ΣN coupling

– 12ΛB[2][3][4]

• Consistency check with the past experiments• Check analysis progress

– 52ΛV• Single particle energy • For measurements with heavier targets

[1] S.N.Nakamura et al., PRL 110, 012502 (2013)[2] T.Miyoshi et al., PRL 90, 232502 (2003)[3] L.Yuan, PRC 73, 044607 (2006)[4] M.Iodice, PRL 99, 052501 (2007)

Contents

• Introduction• Experimental setup• Analyses• Missing mass• Summary

HES

Experimental setup(E05-115 @ JLab Hall-C)

10 msr

10 msr

Contents

• Introduction• Experimental setup• Analyses• Missing mass• Summary

Analysis

Analysis

x, x’, y, y’x, x’, y, y’

p, x’, y’p, x’, y’

@ Reference plane @ Reference plane

@ Target

Missing Mass

Energy scale calibration

x, x’, y, y’ @ RP

e, K+

p, x’, y’@ Target

Inverse transfer matrix

Polyethylene target (0.45 g/cm2)

FWHM ~ 1.8 MeV

Contents

• Introduction• Experimental setup• Analyses• Missing mass• Summary

10ΛBe, 12

ΛB histograms

NsΛ~190

12C(e,e’K+)12ΛB

10B(e,e’K+)10ΛBe

sΛ

pΛ

FWHM~0.9 MeV

FWHM~0.9 MeV

Accidental Background

Accidental BackgroundQuasi-free Λ

Quasi-free Λ

NsΛ~530

sΛPreliminary

Preliminary

T.Motoba et al., PTP Supplement 185 ( 2010 )

Analyses are in progress to achieve better energy resolution with keeping good linearity.

Summary and outlook

• JLab E05-115 (2009)– Λ, Σ0, 7

ΛHe, 9ΛLi, 10

ΛBe, 12ΛB, 52

ΛV– Analyses are in progress• Matrix tuning• Blind analysis• Efficiencies

E05-115 collaboration

Backup

New challenging experiment

Λ, Σ0

Elementary process Energy scale calibration

12ΛB Consistency check

27ΛMg, 48

ΛSc Deformation

208ΛTl

Single particle energy

1m

p

n

γ*

ΛK+

e-

target nucleus

(e,e’K+) spectroscopy

New challenging experiment

Λ, Σ0

Elementary process Energy scale calibration

12ΛB Consistency check

27ΛMg, 48

ΛSc Deformation

208ΛTl

Single particle energy

4ΛH Charge symmetry breaking

1m

p

n Λ

π-

target nucleus

(e,e’K+) spectroscopy

Decayed pion spectroscopy

New challenging experiment

Λ, Σ0

Elementary process Energy scale calibration

12ΛB Consistency check

27ΛMg, 48

ΛSc Deformation

208ΛTl

Single particle energyDesign and setup • 3-D magnetic field calculation• Monte Carlo simulation

Experimental operationAnalyses

• Energy scale calibration• Tracking

1m

4ΛH Charge symmetry breaking

Decayed pion spectroscopy

(e,e’K+) spectroscopy

Background events in the HKS

z [cm]

y [cm]

x [cm] KDC1

KDC2

KDC1

KDC2

9Be , 38.4 [μA]REAL DATA SIMULATION

e+

• 52Cr target– Luminosity ( 1/10 )– Worse S/N – Tracking is not easy

Tracking efficiency and residual

σ ~ 160 μm

Plane efficiency Tracking residual

σ ~ 350 μm

52Cr(e,e’K+)52ΛV

Preliminary

Accidental Background

Quasi-free Λ

Nbind~870

Hit wire selection

REAL DATA

Black : hit wires Blue : selected wiresRed : track

52Cr Target

REAL DATACH2 Target

Compared to the conventional codeNumber of K+ +130%Analysis time – 30%

CUT

CUT

軽い核のミッシングマス

数、分解能

JLab E05-115, Carbon (112mg/cm2)

10LBe

Energy scale calibration

Angle, position @ FP

e, K+

Angle, momentum @ Target

6th order transfer matrix

conversion

Mx – MΛ < 100 keV/c2

トラッキング困難

REAL DATA REAL DATA

Black : hit wires Blue : selected wiresRed : track

CH2 Target H2O Target

52LV

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]

HKS-HES Collaboration Meeting, T.Gogami 29

B.G. mix rate (real data)

ab

B.G mix rate =

* hks ntulpeHKS-HES Collaboration Meeting, T.Gogami 30

e+ simulation

SIMULATION

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

of e+ generated in target

HKS-HES Collaboration Meeting, T.Gogami 31

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

p

n

γ*

ΛK+

e-

e + p ➝ e’ + K+ + Λe e

target nucleus

Feynman diagram

uud

ussud

–pK+

Λ

γ*

~ 1990’s The (K-,π-) , (π+,K+) reactions• Energy resolution ~ a few MeV• n Λ

e’-Spectrometer

K+-Spectrometer

pe’

pK+

Coincidence Missing Mass HHY

32

2000~The (e,e’K+) reaction• Energy resolution ~0.5 MeV• p Λ

2012/9/14 JPS meeting in Kyoto , Toshi Gogami

Background events in the HKS

z [cm]

y [cm]

x [cm] KDC1

KDC2

KDC1

KDC2

9Be , 38.4 [μA]REAL DATA SIMULATION

~2.24

~4.94

e+

• 52Cr target– Luminosity ( 1/10 )– Worse S/N – Tracking is not easy

10ΛBe, 12

ΛB histograms

NsΛ~190

12C(e,e’K+)12ΛB10B(e,e’K+)10

ΛBe

sΛ

pΛ

FWHM~0.9 MeVFWHM~0.9 MeV

Accidental BackgroundAccidental Background

Quasi-free ΛQuasi-free Λ

NsΛ~530

sΛ

Preliminary Preliminary

Experimental motivation• JLab E05-115 (2009, Hall-C)– Elementary processes (Λ,Σ0)– 7

ΛHe[1], 9ΛLi, 10

ΛBe• ΛN charge symmetry breaking• ΛN-ΣN coupling

– 12ΛB• Consistency check with the past experiments• Check analysis progress

– 52ΛV• Single particle energy (systematic な study)• ls splitting, core-configuration mixing• 将来重く行くため避けられない道

[1] S.N.Nakamura et al., PRL 110, 012502 (2013)

Detectors & Trigger

K+

p, π+e-

Drift chambers

TOF walls (Plastic scintillators)

Cherenkov detectors • Aerogel (n=1.05)• Water (n=1.33)

HESHKS

HKS trigger(TOF1x2x3) x Chrenkov

~10 kHz

HES trigger(TOF1x2)

~2000 kHz

Coincidence triggerHES x HKS

< 2 kHz2012/10/6 Core2Core in Barcelona, Toshi Gogami 36

52Cr(e,e’K+)52ΛV

Mixed event analysis をやる

s

pd

f

数 Preliminary

Electro-production of K+Λ

JLab E05-115 experiment by the (e,e’K+) reactionSmall Q2 ( ~0.01 [GeV/c]2 ) almost real photon

Real photon

2013/3/27 JPS meeting in Hiroshima , Toshi Gogami 38

An importance of measurement of K+Λ production at forward angles

At forward angles– Data show lack of consistency– We can access θK

cm ~ 15 deg

P.Bydzovsky and T.Mart, Phys. Rev. C 76, 065202 (2007)

2013/3/27 JPS meeting in Hiroshima , Toshi Gogami 39

Real photonQ2 = 0 [ GeV/c ]2

Λ, Σ0 from polyethylene ( CH2 )target

JPS meeting in Hiroshima , Toshi Gogami2013/3/27

Preliminary

40

Λ, Σ0 from CH2 target

JPS meeting in Hiroshima , Toshi Gogami2013/3/27

Preliminary

41

p(e,e’K+)Λ~1.8MeV (FWHM)Δm = 19 ± 17 keV/c2

p(e,e’K+)Σ0

~1.8MeV (FWHM)Δm = 73 ± 47 keV/c2

JLab E05-115CH2, ~ 450 [mg/cm2]~ 2.0 [μA]~ 38 [hours]

Cross sections

2013/3/27 JPS meeting in Hiroshima , Toshi Gogami 42

SAPHIR : K.H. Glander et al. , Eur. Phys. J. A 19, 251-273 (2004)CLAS : R. Bradford et al. , Phys. Rev. C 73, 035202 (2006)

γ(*) + p K+ + Λ γ(*) + p K+ + Σ0

Preliminary 200 ± 16 ± 91

Preliminary 85 ± 13 ±34

Cross sections

2013/3/27 JPS meeting in Hiroshima , Toshi Gogami 43

SAPHIR : K.H. Glander et al. , Eur. Phys. J. A 19, 251-273 (2004)CLAS : R. Bradford et al. , Phys. Rev. C 73, 035202 (2006)JLab E94-107 : P. Markoviz et al. , Proceedings of SENDAI08 (2009)JLab E91-016 : F. Dohrmann et al. , arXiv 0707.3059v2 (2007)

γ(*) + p K+ + Λ γ(*) + p K+ + Σ0

Preliminary 200 ± 16 ± 91

Preliminary 85 ± 13 ±34

Q2 dependence (JLab E05-115)

JLab E05-115, CH2 target

Preliminary

2013/3/27 JPS meeting in Hiroshima , Toshi Gogami 44

W = 1.93 GeVθCM = 17 degrees

実光子(SAPHIR)

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

JPS meeting in Kyoto , Toshi Gogami 452012/9/14

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

JPS meeting in Kyoto , Toshi Gogami 462012/9/14

Detectors & Trigger

K+

p, π+e-

Drift chambers

TOF walls (Plastic scintillators)

Cherenkov detectors • Aerogel (n=1.05)• Water (n=1.33)

HESHKS

2012/10/6 Core2Core in Barcelona, Toshi Gogami 47

Detectors & Trigger

K+

p, π+e-

Drift chambers

TOF walls (Plastic scintillators)

Cherenkov detectors • Aerogel (n=1.05)• Water (n=1.33)

HESHKS

HKS trigger(TOF1x2x3) x Chrenkov

~10 kHz

HES trigger(TOF1x2)

~2000 kHz

Coincidence triggerHES x HKS

< 2 kHz2012/10/6 Core2Core in Barcelona, Toshi Gogami 48

Coincident K+ Identification (OFF-LINE)

2012/10/6 Core2Core in Barcelona, Toshi Gogami 49

Cherenkov selection Coincidence time selectionAerogel (n=1.05)Water (n=1.33)

K+

π+

p

CUT

CUT

p cut π+ cut

= HKST - HEST

( e,e’p )

( e,e’π+ )

CUT

CUT

( e,e’K+ )

Coincidence of (e,e’K+) selection

CUT

CUT

mK2 selection

Coincident K+ : ~90% ( π+ : < 1% , p : < 2% )

10ΛBe, 12

ΛB histograms

NsΛ~190

12C(e,e’K+)12ΛB10B(e,e’K+)10

ΛBe

sΛ

pΛ

FWHM~0.9 MeVFWHM~0.9 MeV

Accidental BackgroundAccidental Background

Quasi-free ΛQuasi-free Λ

NsΛ~530

sΛ

Preliminary Preliminary