E05-102 Analysis Update:

Asymmetry Measurements in Quasi-Elastic Scattering

Ge JinUniversity of Virginiafor Jefferson Lab E05-102 Collaboration

e-He3

Outline asymmetry

measurements Motivation Experimental Setup BigBite Calibration

Inclusive asymmetry and neutron form factors extraction PWIA Formulism Inclusive Asymmetry Results GE

n Extraction Results

)',e(He3 e

p)e',e(He and d)pe',e(He 33

3He spin structure

Spin-1/2 Particle, 3 spin-1/2 Nucleons (Proton and Neutron)

Angular Momentum l=0 l=0 l=2 ~90% ~1-2% ~8%

EffectiveNeutronTarget

Theoretical asymmetry from Faddeev Calculation

BigBite optics and scintillator calibration

Sieve

Target calibration Wall thickness 3He density

(absorbing spectra) Polarization

Run-by-run EPR polarization

NMR ongoing Dilution factor pass HRS-L(%) HRS-R

1st 98±3 96±3

2nd 96±3 96±3

3rd 96±3 96±3

Inclusive GEn Extraction

(Q2=0.95 GeV2)

3He Inclusive Responses at Q.E. peak Transverse:

Longitudinal:

where H’s are described by momentum distribution within PWIA

A. Kievsky, E. Pace, G. Salme’ and M. Viviani, PRC 56 (1997) p.64

])()(2[2

]2[2

'2

'2

2

'

'''

3

3

Tnn

MTpp

MTHe

TLnn

MnETL

ppM

pETL

He

HGHGqM

QR

HGGHGGR

Neutron: HnProton: Hp

T’

Proton: HpTL’

Quasi-elastic asymmetry

ctiond_cross_seunpolarize

)*cos*cos*(sin '''''

33

THe

TTLHe

TLMottTL

RvRvA

where v’s are kinematics factors, θ and φ describe the directionbetween q vector and target polarization

T. D. Donnelly and A. S. Raskin, Ann. Phys 169, 247 (1986)

Ratio of Inclusive Asymmetry ATL’/AT’

Longitudinal:

Transverse:

Asymmetry ratio:

Where v’s are kinematics factors

By measuring ATL’/AT’ and using GEp , GM

n , GMn

as known parameters can one extract GEn

ctiond_cross_seunpolarize

)*cos*cos*(sin

]))()(2[2

(

])2[2(

ctiond_cross_seunpolarize

ctiond_cross_seunpolarize

'''''

'2

'2

2

'

'''

'

'

'''

'''

33

3

3

THe

TTLHe

TLMottTL

Tnn

MTpp

MT

TLnn

MnETL

ppM

pETL

T

TL

THe

TMottT

TLHe

TLMottTL

RvRvA

HGHGqMQ

v

HGGHGGv

A

A

RvA

RvA

Asymmetry Results Kinematics:

3 pass beam, HRS-R 170, Q2=0.95 GeV2

Analysis: Asymmetry in 0.9<x<1.1 Yawei Zhang’s target and dilution

factor analysis Karl Slifer’s radiative correction code

radcor.f Results:

ATL’=-0.55±0.09(stat)±0.04(syst)% AT’ =3.12±0.10(stat)±0.21(syst)%

Error: Stat error dominates ATL’ Syst error contributed by beam and

target polarization, and dilution factor

Asymmetry Ratio and GEn Extraction

Ratio: ATL’/AT’ =-0.18±0.032(stat)±0.004(syst)

Error Dominated by stat in ATL’ case Small sensitivity systematically

GEn Extraction

GEn/GD=0.26±0.047(stat)±0.005(syst)±(theory)

or GEn=0.048±0.0086(stat)±0.0009(syst)±(theory)

Using J. Kelly’s parameterization for GEp , GM

n , GMn

World GEn Data

J. J. Kelly, PRC 068202, 2004

S. Riordan, thesis, 2008

Comments and Outlook Further theoretical support (at and

around Q.E peak) Advantages:

Single arm (HRS) detector calibration Higher Q2 with stronger GE

n contribution in ATL’

Big save of beam time: 18% accuracy in 2-day running

Double-ratio method insensitive to systematic error

Graduate StudentsG. Jin, University of Virginia

E. Long, Kent State UniversityM. Mihovilovič, Jožef Stefan Institute

Y. Zhang, Lanzhou University

Run CoordinatorsA. Camsonne, Jefferson Lab

P. Monaghan, Hampton UniversityS. Riordan, University of VirginiaB. Sawatzky, Temple UniversityR. Subedi, University of Virginia

V. Sulkosky, MITY. Qiang, Duke University

B. Zhao, College of William and Mary

S. GolgeO. Hansen

T. HolmstromJ. Huang

H. IbrahimE. JensenM. JonesH. KangJ. Katich

C. W. KeesP. King

J. LeRoseR. Lindgren

H. LuW. Luo

K. AlladaB. AndersonJ. R. M. AnnandW. BoeglinP. BradshawM. CananC. ChenR. De LeoX. DengA. DeurC. DuttaL. El FassiD. FlayF. GaribaldiH. GaoR. Gilman

P. MarkowitzM. MezianeR. Michaels

B. MoffitN. MuangmaH. P. Khanal

K. PanD. Parno

E. PiasetzkyM. Posik

A. J. R. PuckettX. QianX. Qui

A. Saha

Thanks to the Hall A Quasi-ElasticFamily Experiments

SpokespersonsT. Averett, College of William and Mary (E05-015, E08-05)

J. P. Chen, Jefferson Lab (E05-015)S. Gilad, MIT (E05-102)

D. Higinbotham, Jefferson Lab (E05-102, E08-005)X. Jiang, Rutgers University (E05-015)

W. Korsch, University of Kentucky (E05-102)B. E. Norum, University of Virginia (E05-102)

S. Sirca, University of Ljubljana (E05-102)V. Sulkosky, MIT (E08-005)

E05-015,E08-005,and E05-102

CollaborationF. Salvatore

M. ShabestariA. ShahinyanB. Shoenrock

J. St. JohnA. Tobias

W. TiremanG. M. Urciuoli

D. WangK. WangJ. Watson

B. WojtsekhowskiZ. Ye

X. ZhanX. Zheng

L. Zhu