Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update...

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Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction -Analysis Update of the Jlab Experiment E05115- Chunhua Chen Hampton Universithy

Transcript of Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update...

Page 1: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

Spectroscopic Investigation of P-shell Λ

hypernuclei by the (e,e'K+) Reaction

-Analysis Update of the Jlab Experiment

E05115-

Chunhua ChenHampton Universithy

Page 2: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

Outline

Experimental Goal of E05115

Kinematics of the E05115

Experimental Setup of E05115

System calibration procedure and status

Preliminary results

Summary and to do

Page 3: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

Experimental GoalThe 3rd Generation Hypernuclear Spectroscopy in JLab-HallC

Spectroscopy of Medium - heavy hypernucleus

52Cr(e,e’K+) 52LV

L single particle nature in the mean field

quark picture vs. conventional pictureSpectroscopy of Light L hypernuclei

LN interactions, ls splitting, Charge Symmetry Breaking

p shell hypernuclei : 12C(e,e'K+)12ΛB , 7Li(e,e'K+)7

ΛHe, 10B(e,e'K+)10ΛBe ,

and 9Be(e'K+)9ΛLi

Calibration by the elementary process p(e,e’K+)Λ or Σ: H2O and CH2

Page 4: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

Kinematics of the E05-115 Experiment

+p →+K+

Momentum: 2.344GeV/c

Momentum: 0.844GeV/c ±17%Angular acceptance: 3°〜 9°

Momentum: 1.2GeV/c ±12.5%

Angular acceptance : 1°〜 13°

1.5GeV γ*

Scattered electron

K+

Electron beam

Target nucleus

pCoincidence

measurement

Page 5: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

Experimental Setup

Splitter Magnet

HKS

HES

Page 6: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

PreChicane-SPL-(HKS+HES) Configuration

Page 7: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

Experimental Setup -Detector Package-

HES-D

e’

EHOD2

EHOD1

EDC2EDC1

HES Detectors

Page 8: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

Calibration Procedure of the Spectrometer System

Forward Tuning

Backward tuning

mass spectroscopy

Nonlinear Least Chi2 fitting

Kinematical scan

Initial state

Magnetic field study

Geant4 Simulation Focal plane pattern

Real Data

Λ & Σ mass spectroscopy

Field map

Focal plane pattern

Matching level A

SS pattern SS hole

Matching level

B

Kinematical parameters

Independent level C

matrices

A&B&C

Page 9: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

Forward Optics Tuning

Purple: Real HKS SS data Blue: Geant4 Simulation Splitter field contour on xoz plane

The leakage of splitter fringe field causes the cross talk between the splitter and quadrupoles

Purple: Geant4 simulation green: Real HES SS data

Target

Beam Kaon

Q1

Q2

Page 10: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

Forward Optics Tuning

The asymmetry functions are introduced and tuned for HKS&HES quadruple field Bx and By, independently.

Page 11: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

The Mass Status of Forward Optics Tuning

Start Point

after forward tuning 11

Page 12: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

Backward Calibration Procedure

= = (Ebeam , Pk , xt’k, yt’k , Pe, , xt’e, ,yt’e’ )

(1+δ/100)

Nonlinear least 2 fitting

ΔEbeam0

optimization

Kinematical Calibration

Optical Calibration

MomentumMatrix

AngleMatrix

ΔPK,ΔPe optimization

Beam Energy Scan

iterate

iterate

+

𝜒22=𝜔 Λ (𝜎 Λ

𝑓𝑖𝑡 )2/¿𝜎 Λ>¿2+¿𝜔Σ (𝜎Σ

𝑓𝑖𝑡 )2/¿𝜎 Σ>¿2+𝜔𝑔𝑠(𝜎 𝑔𝑠

𝑓𝑖𝑡 )2/¿𝜎𝑔𝑠>¿2 ¿¿¿¿

gs : 12ΛBgs

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Start Point

Fitting Function:Cauchy+pol3

Particle Mean(MeV) FWHM

Λ 0.4495 2.832

Σ0 76.74 3.27

σ~2.7MeV

H2O target Beam Momentum: 2.344GeV/c + 20 MeV/c

FWHM~2.6MeV

Page 14: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

Preliminary Status

#1

#2

Peak# Mean(MeV) σ (MeV)

1 -11.39 0.367

2 -0.40 ~1.8

FWHM~1.675MeV

FWHM~1.775MeV

FWHM~1.565MeV

FWHM~2.0MeV

Page 15: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

Preliminary Result 7ΛHe

E01011 data

E. Hiyama, et al., PRC53 2078 (1996)

n

n

6He core3/2+&5/2+

Page 16: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

Preliminary Result 10ΛBe – 10

ΛBe

3/2-0.00

5.59 3/2-

7/2-6.38

5/2-7.94

2.43 5/2-1/2-2.78

1/2+1.68

5/2+3.04

3/2+4.70

9/2+6.76

Low Lying 9Be Level Structure

1-2-

(< 0.1)10

Be

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Missing mass status – 9LLi

Hall A Result(To be published soon)

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Summary and to do

By current calibration method, we are able to get clear

mass spectroscopy , which is not included in the calibration

data set;

Current resolution is still factor of 2 away from expected

resolution, the iteration will continue to improve the

optical matrices as well as the kinematics;

Other issue: High multiplicity tracking problem for heavy

target data.

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Back up

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New Data Sets

All carbon runs with clear beam current and

nominal beam energy.There are around 414 events in peak #1, and the S/N is around 2.35.

#1

The improvement of the resolution is small with the old

data, since the statistic of 12ΛBgs is small, which is

momentum sensitive .

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ProblemSince the improvement of the resolution still small, increase the weight of 12

ΛBgs by factor of 4 on the base of the statistical weight .

7ΛHe Missing Mass

σ ~ 1.0 MeV

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Target Straggling

σ~3.2MeV

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First turn of optics tune with CH2 Data

1. There is still kinematical parameters dependence of Λ and Σ

(1-2MeV) after forward optical tuning;

2. Counts of 12ΛB from low luminosity data is small, and also its

resolution is bad, the S/N ratio of selected region is small;

σ~2.7MeV

Tune Angle matrix and momentum

matrix at same time

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Preliminary Status -7

ΛHe-

E01011 data

Resolution : ~510 keV (FWHM) for g.s.Data taking : ~30 hours w/ 30 mA

Peak # Mean(MeV) σ (MeV)

1 -5.46 0.549

2 -3.94 4.66

Theoretical calculation Binding energy: Hiyama w/o CSB

1/2+ (-BΛ=-5.37)

#1#2

Page 25: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

First turn optics tune with CH2 Data

Particle Mean(MeV) FWHM

Λ 0.2098 2.122

Σ0 77.41 2.456

Page 26: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

First turn optics tune with CH2 Data

FWHM~2.9MeV

H2O target

FWHM~2.6MeV

H2O target Beam Momentum: 2.344GeV/c + 20 MeV/c

Page 27: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

First turn optics tune with CH2 Data

FWHM~2.9MeV

H2O target

FWHM~2.6MeV

H2O target Beam Momentum: 2.344GeV/c + 20 MeV/c

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Target Mass Events # above BG S/N

CH2 Λ 9976 3.54

Σ0 2650 1.40

H2O(Pe~2.364) Λ 283 2.96

C12 (BC=20uA) 309 1.61

Data sets

Page 29: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

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

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e+

HKS

Page 30: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

Calibration procedure-Beam Energy Scan-

𝜒12=𝜔 Λ(𝑚 Λ

𝑓𝑖𝑡−𝑚Λ0 )/𝜎 Λ

2+¿𝜔Σ(𝑚Σ𝑓𝑖𝑡−𝑚Σ

0 )/𝜎 Σ2 ¿

𝜒22=𝜔 Λ(𝜎 Λ

𝑓𝑖𝑡)/¿𝜎 Λ>¿2+¿𝜔Σ (𝜎 Σ

𝑓𝑖𝑡)/¿𝜎 Σ>¿2+𝜔𝑔𝑠(𝜎 𝑔𝑠

𝑓𝑖𝑡) /¿𝜎𝑔𝑠>¿2 ¿¿¿¿

ωi:statistic weigth

Page 31: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

Coincident

Time: The correlation of HKS target time and HES target time, give us the coincident spectrum:

Real events

Accidental

Ktar

etarcoin TTT '

PID cut is applied and path length has been done

Coincident Trigger Set

HKS :

HKStrigger=(CP)×(K)

CP=(KTOF1X)×(KTOF1Y)×(KTOF2X)

K=WC×

HES:

HEStrigger=(EHODO1)×(EHODO2)

×:AND

COINtrigger=(HKStrigger)×(HEStrigger)

Page 32: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

Kinematics of the E05-115 Experiment

Momentum: 2.344GeV/c

Momentum: 0.844GeV/c ±17%Angular acceptance: 3°〜 9°

Momentum: 1.2GeV/c ±12.5%

Angular acceptance : 1°〜 13°

1.5GeV γ*

Scattered electron

K+

Electron beam

M.Q.Tran et al. PLB445 (1998) 20

+p →+K+

Target nucleus

pCoincidence

measurement

Page 33: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

Preliminary Status

#1

#2

Peak# Mean(MeV) σ (MeV)

1 -11.39 0.367

2 -0.40 ~1.8

FWHM~1.675MeV

FWHM~1.775MeV

FWHM~1.565MeV

FWHM~2.0MeV

#1 #2

FWHM~1.675MeV

FWHM~1.565MeV

Page 34: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

Spectrometer System Calibration-Minimize -

Kinematics calibration: utilizing well known masses of , produced from CH2 , 12

ΛBgs from 12C to determine binding energy to a level of precision ~100keV

Optical calibration: Minimize Chisquare w.r.t reconstruction matrix M by an Nonlinear Least Square method.

Mgs: fitted meanMΛ &MΣ : theoretical dataωi : statistic weigth

𝜒12=𝜔 Λ(𝑚 Λ

𝑓𝑖𝑡−𝑚Λ0 )/𝜎 Λ

2+¿𝜔Σ(𝑚Σ𝑓𝑖𝑡−𝑚Σ

0 )/𝜎 Σ2 ¿

𝜒22=𝜔 Λ(𝜎 Λ

𝑓𝑖𝑡)/¿𝜎 Λ>¿2+¿𝜔Σ (𝜎 Σ

𝑓𝑖𝑡)/¿𝜎 Σ>¿2+𝜔𝑔𝑠(𝜎 𝑔𝑠

𝑓𝑖𝑡) /¿𝜎𝑔𝑠>¿2 ¿¿¿¿

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Page 36: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

PreChicane-SPL-(HKS+HES) Configuration

Page 37: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

Calibration Data Set

Target CH2 12C H2O

Mass Λ Σ Λ12B Λ

Beam P(MeV/c) ~2.344 ~2.344 2.364

Beam Current(uA) ~2 ~20 ~3.5

Page 38: Spectroscopic Investigation of P-shell Λ hypernuclei by the (e,e'K + ) Reaction - Analysis Update of the Jlab Experiment E05115 - Chunhua Chen Hampton.

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Mass spectroscopy ofΛ,Σ and 12

ΛB(mean and peak

width)