Patrizia RossiLaboratori Nazionali di Frascati- INFN (Italy)

Physics motivations

Experimental Requirements

Measurements

Summary

CLAS12 2nd European Workshop - March 7-11, 2011- Paris, France

SIDIS ProgramSIDIS Program with Longitudinally Polarized with Longitudinally Polarized TargetsTargets

E12-07-107 : E12-07-107 : Studies of Spin-orbit Correlations with Longitudinally Polarized TargetSpokespersons: H. Avakian, P. Bosted, K. Griffioen, K. Hafidi, P. Rossi

E12-09-009 : E12-09-009 : Studies of Spin-Orbit Correlations in Kaon Electroproduction in DIS with polarized hydrogen and deuterium targetsSpokespersons: H. Avakian, E. Cisbani, K. Griffioen, K. Hafidi, P. Rossi

E12-09-007 : E12-09-007 : Studies of partonic distributions using semi-inclusive production of kaonsSpokespersons: K. Hafidi, H. Avakian, F. Benmokhtar, A. EL Alaoui, M. Mirazita

TMDs TMDs with Longitudinally Polarized Targets at l.t.with Longitudinally Polarized Targets at l.t.

Factorization of kT-dependent PDFs proven at low PT of hadrons (Ji et al)

Quark polarization

Nucl

eon

pola

riza

tion

-

Correlation between the transverse momentum and transverse spin of quarks in longitudinally polarized nucleon

Kaon distributions in ep e’KXKaon distributions in ep e’KX

Q2>1GeV2

W2>4 GeV2(10)y<0.85MX>2GeV

SIDIS kinematics

High energy kaons are at small angles (<30o)

forward

Flavor DecompositionFlavor Decomposition

BBS/LSS +OAM

BBS/LSS

H.Avakian,S.Brodsky,A.Deur,F.Yuan (2007)

AA11 – P – PTT dependence dependence

M. Anselmino et al PRD74:074015, 2006

+ A1 suggests broader kT distributions for f1 than for g1

- A1 may require non-Gaussian kT-dependence for different helicities and/or flavors

02=0.25GeV2

D2=0.2GeV2

H. Avakian & CLAS Coll., PRL.105:262002, 2010

0.4<z<0.7

AA11 – P – PTT dependence @ 12 GeV dependence @ 12 GeV

A1 PT-dependence provides access to helicity dependence of kT-distributions of quarks

Deuteron and hydrogen data required for PT-dependent flavor decomposition.

proton

Curves: M. Anselmino et al PRD74:074015, 2006

A1

deuteron

A1

Transverse momentum distributions of Transverse momentum distributions of partons partons

NJL model H. Matevosyan et al. arXiv:1011.1052 [hep-ph]

proton

Transverse momentum distributions in hadronization may be flavor dependent => measurements of different final state hadrons is required

Transverse momentum distributions in hadronization may be flavor dependent => measurements of different final state hadrons is required

Kotzinian-Mulders AsymmetryKotzinian-Mulders Asymmetry

B.Musch arXiv:0907.2381B.Pasquini et al, arXiv:0910.1677

Kotzinian-Mulders Asymmetry for and K provides complimentary information on polarization effects in hadronization

CLAS12 has wide coverage in x and PT, which is crucial for this program

Kotzinian-Mulders AsymmetryKotzinian-Mulders Asymmetry

proton deuteron

Partonic SIDIS: Partonic SIDIS: E12-09-007E12-09-007Complete program for the study of the individual quark

contribution to the nucleon spin

Partonic SIDISPartonic SIDIS

Ke

e’

Sea strange quark polarization

Light quark sea polarization asymmetry

-Most sensitivity to K- (us)

Experimental configurationExperimental configuration

RIC

HRIC

H

CLAS12 + RICH

Target: longitudinally polarized NH3 (P=0.85%) & ND3 (P=0.40%) Luminosity= ∼ 1035 cm−2s−1

Ee = 11GeV

Proposal Physics PAC days Parallel Running

E12-07-107 TMDs 103(50 d, 30 p)

E12-06-109

E12-09-009 TMDs K 103(50 d, 30 p)

E12-06-109, E12-07-107

E12-09-007(b) Partonic SIDIS

103 (50 d, 30 p)

E12-06-109, E12-07-107

Polarized targetPolarized targetDesign Parameters:• L = 2 x 1035 N/cm2 e-/s =>

3.3 cm length, 16 nA beam rastered over 3 cm diameter (anneal once every 1-2 days)

• p and d targets (also C, empty)

• Pt=80(40)% p(d) via DNP

• Horizontal 1 K cryostat (0.8 W), 5 T field from CLAS12 CT solenoid, 140 GHz µwave (1/2 W), irradiated NH3/ND3, NMR to measure Pol.)

Recent Progress:• Funding provided through NSF MRI-R2 grant to ODU

(lead), CNU and UVa (4/’10 - 3/’14)• Refrigerator design led by UVa/Jlab• Development of NMR started at ODU (with help from

UVa and JLab); some equipment purchased• Development of µwave system started at CNU

ConclusionsConclusions

Comprehensive program to study transverse momentum dependence of valence quark transverse and longitudinal spin distributions through measurements of spin-azimuthal asymmetries in SIDIS electroproduction of pions and kaons

Main objectives include studies of correlations of the transverse spin of quarks with their transverse momentum, leading to the sin 2φ azimuthal moment.

The PT dependence of the double spin asymmetry will provide additional information on the flavor and polarization dependence of transverse momentum dependence of helicity distributions of quarks, providing complementary to SSA measurements access to spin-orbit correlations.

11 GeV polarized electron beam, longitudinally polarized proton and deuteron targets and the CLAS12 detector equipped with a RICH detector for kaon studies will be used.

Complete program for the study of the individual quark contribution to the nucleon spin

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