Λ hypernuclear spectroscopy at Jefferson Lab

Λ hypernuclear spectroscopy

at Jefferson LabThe 3rd Korea-Japan on Nuclear and

Hadron Physics at J-PARC, at Inha University in Korea

2014/3/20 – 2014/3/21

Graduate school of Science, Tohoku Univ.Toshiyuki Gogami

Contents• Introduction• (e,e’K+) reaction experiment• JLab E05-115

• Analysis• Energy scale calibration• Binding energy systematic error estimation

• Results• 12C(e,e’K+)12

ΛB• 7Li(e,e’K+)7

ΛHe





ΛHe

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

pn

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 sub-MeV• p Λ

High intensity (~1014 Hz)Small emittance (2 μm ・mrad)Small energy spread (ΔE/E < 10-4)

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

pn

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 sub-MeV• p Λ

High intensity (~1014 Hz)Small emittance (2 μm ・mrad)Small energy spread (ΔE/E < 10-4)

JLab E05-115 (2009)

Physics motivation for JLab E05-115• 7

ΛHe• CSB effect in ΛN interaction• Λ Glue like role

• 10ΛBe• CSB effect in ΛN interaction• Λ Glue like role• Level inversion due to nuclear deformation

• 12ΛB• Consistency confirmation with old data• Finer structures with best resolution

• 52ΛV (the first challenge for medium-heavy mass region)• Λ single particle potential

Physics motivation for JLab E05-115• 7

ΛHe• CSB effect in ΛN interaction• Λ Glue like role

• 10ΛBe• CSB effect in ΛN interaction• Λ Glue like role• Level inversion due to nuclear deformation

• 12ΛB• Consistency confirmation with old data• Finer structures with best resolution

• 52ΛV (the first challenge for medium-heavy mass region)• Λ single particle potential

7ΛHe

hyprenucleus

Λαn

n

Λ

αnn

+

6He 7HeΛ

Resonant state

Bound state

Unbound Bound

CSB effect

CSB interaction test in A=7 iso-triplet comparison

Λpαn

Λpαp

Λαn

n

7ΛBe

7ΛLi

7ΛHeCo

unts

Coun

tsCo

unts

BΛ [MeV]

H.Tamura et al., PRL 84, 5963 (2000)


Λpαn

Λpαp

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

JLab E01-011-5.68 ± 0.03 ± 0.25

Λαn

n

+

7ΛHe in JLab E05-115


+

Resonant state

Bound state

Unbound Bound

CSB effect

JLab E05-115• Small systematic error • Observation of the excited state

-BΛ(1/2+) = -5.68 ± 0.03 ± 0.25

Experimental setup

Pre-chicane beam lineΔp/p ~ 2 × 10-4

Δp/p ~ 2 × 10-4

θe’ = 6.5 ± 5.0 [degree]θK = 5.7 ± 4.6 [degree]

Experimental setup

Experimental setup

Target ([mg/cm2]) HypernucleusHyperon

Nominal beam current [A]

Run time [h] Total incident charge [C](Number of incident e-)

CH2 (450) Λ, Σ0, 12ΛB 2.0 39 0.28 (0.171019)

H2O (500) Λ, Σ0, 12ΛN 2.5 21 0.20 (0.121019)

7Li (208) 7ΛHe 35 42 4.84 (3.01019)

9Be (188) 9ΛLi 40 39 5.33 (3.31019)

10B (56) 10ΛBe 40 45 6.25 (3.91019)

12C (88) 12ΛB 20, 35 55 5.73 (3.61019)

52Cr (154) 52ΛV 7.5 230 6.35 (4.01019)





ΛHe

Absolute energy scale calibration with Λ and Σ0

x, x’, y, y‘ @ RP

p, x’, y’ @ Target Missing mass

Reference plane

Target

Backward transfer matrix

Absolute energy scale calibration with Λ and Σ0

x, x’, y, y‘ @ RP

p, x’, y’ @ Target Missing mass

Backward transfer matrix

Tune

ITERATION

Λ,　 Σ0 comparison

Before(Δp/p ~ 10-3)

After(Δp/p ~10-4)

4 MeV (FWHM)

1.6 MeV (FWHM)

~ 0.5 MeV (FWHM) for 12ΛB

Λ,　 Σ0 comparison

Before(Δp/p ~ 10-3)

After(Δp/p ~10-4)

4 MeV (FWHM)

1.6 MeV (FWHM)

~ 0.5 MeV (FWHM) for 12ΛB

How good is the binding energy determined ?(Systematic error)

Systematic error estimation for binding energy

( TOSCA + Geant4 )


RealisticS/NYieldsEnergy straggling in targetBeam rasterSpectrometer acceptanceDetector resolution



Com

pare



Com

pare

keV





ΛHe

Definition of differential cross section

Number of virtual photonincluding HES acceptance

Number of target nucleus EfficienciesHKS acceptance

12C(e,e’K+)12ΛB spectrum

Preliminary

sΛ

pΛ


(FWHM: 0.5 MeV)

Preliminary

12ΛC and 12

ΛB comparison

(FWHM: 0.5 MeV)

Preliminary

H.Hotch et al., PRC64, 044302 (2001)

12ΛC

12ΛB

(FWHM: 1.4 MeV)

D.J.Millener, NPA691, 93 (2001)

T.Motoba et al., PTP suppl. 185, 224 (2012)

A.Matsumura, Doctor’s thesis (2009)

12ΛC12

ΛB

JLab E01-011

KEK E369

JLab E05-115

Calc.

Calc. ①

①

②

③

③

②

(π+,K+) reaction

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


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

Results for 7Li(e,e’K+)7

ΛHe(FWHM: 1.3 MeV)

𝟏𝟐+¿

,

Resonant state

Bound state

Unbound Bound

CSB effectPreliminary

Results of 7ΛHe

Λpαn

Λpαp


Λαn

n

𝟏𝟐+¿

,

JLab

E05

-115

(Pre

limin

ary)

Preliminary

JLab E01-011-5.68 ± 0.03 ± 0.25

Results of 7ΛHe


𝟏𝟐+¿

,

EΛ (3/2+,5/2+) [MeV]

JLab E05-115 1.900.2 sys. errorE.Hiyama et al., PRC 80, 054321 (2009)

1.70

M.Sotona et al.,PTP 117 (1994)

1.79

EΛ

Summary• JLab E05-115 experiment (2009)• Λ, Σ0, 7

ΛHe, 9ΛLi, 10

ΛBe, 12ΛB and 52

ΛV

• 12ΛB• Best resolution• Consistent with past experiments

• 7ΛHe• 1/2+ with small systematic error• 2+ (core) 3/2+,5/2+ (7

ΛHe) was measured

Outlook

• Systematic error• Fitting to the histogram• 52

ΛV

Backup


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



E05-115 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



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


Λ binding energy for 10B(e,e’K+)10

ΛBePeak - 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 17.31.21.32 -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

Old data (3 points)8.910.60(1)

8.310.61(1)

9.300.26(2)

7Li(e,e’K+)7ΛHe spectrum


Missing mass spectra

9Be(e,e’K+)9ΛLi

52Cr(e,e’K+)52ΛV

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


ΛV


JLab E05-11552Cr (e,e’K+)52

ΛV


ΛV


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

Energy scale calibrationx, x’, y, y‘ @ RP

p, x’, y’ @ Target

Missing mass

Inverse transfer matrix

p : Λ, Σ0 and 12ΛB-s

xp and yp : Λ and Σ0

LOOP

Tune

ITERATION Matrix selection• Widths of Λ, Σ0, 12

ΛB-s

Create new ROOT files

Next LOOP

Li


Λ binding energy for 7Li(e,e’K+)7

ΛHe

E01-011: -5.680.030.25 MeV

(FWHM: 1300 keV)



1 -5.550.10 41320 10.70.52 -3.650.20 24816 6.20.4


𝟏𝟐+¿

,

Preliminary

Λ binding energy for 7Li(e,e’K+)7

ΛHe (331 mg/cm2)

E01-011: -5.680.030.25 MeV

(FWHM: 1300 keV)



1 -5.750.10 46021 10.80.52 -3.840.16 27317 6.50.4

Motivation for the blind analysis

Simulation

K+ momentum

e’ m

omen

tum

Tuning

Tuning OK？LinearitySystematic error

Ee=2.344 GeV

Flow chart of blind analysis

Compare

Blind

Systematic error for binding energy

With distorted matrices With optimized matrices

IN PROGRESS

Experimental setup

Data summary


Λpαn

Λαn

n Λpαp


Λpαn

ΛpαpS.N.Nakamura et al., PRL 110, 012502 (2013)

-5.68 ± 0.03 ± 0.25

Λαn

n

+

Data summary

Target ([mg/cm2]) HypernucleusHyperon

Nominal beam current [A]

Run time [h] Total incident charge [C](Number of incident e-)

CH2 (450) Λ, Σ0, 12ΛB 2.0 39 0.28 (0.171019)

H2O (500) Λ, Σ0, 12ΛN 2.5 21 0.20 (0.121019)

7Li (208) 7ΛHe 35 42 4.84 (3.01019)

9Be (188) 9ΛLi 40 39 5.33 (3.31019)

10B (56) 10ΛBe 40 45 6.25 (3.91019)

12C (88) 12ΛB 20, 35 55 5.73 (3.61019)

52Cr (154) 52ΛV 7.5 230 6.35 (4.01019)

Data summary

Documents

Λ hypernuclear spectroscopy at Jefferson Lab