Study Hadronization by SIDIS at JLab 12GeV Presented by Hai-jiang Lu* (Huangshan College) Beijing U.,California State U., CIAE, Hampton U., INFN, Kentucky U., Lanzhou U., LBNL, Ljubljana U., Maryland U., MIT, Nankai U., ODU, Rutgers U., Seoul National U., Temple U., USTC, UVA A. Afanasev, K.A. Aniol, W. Bertozzi, W. Brooks, A. Camsonne, G.D. Cates, C.C. Chang, J.P. Chen (Co-Sp), S. Choi, E. Chudakov, E. Cisnani, D. Crabb, F. Cusanno,D. Day, R. DeLeo, A. Deur, J. Feng, S. Frullani, F. Garibaldi, S. Gilad, J. Gomez, O. Hansen, D.W. Higinbotham, B.T. Hu, J. Huang, M. Iodice, X. Jiang, Y. Jiang, Ho. Kang, Hy. Kang, W. Korsch, L. Lagamba, J. LaRose, B. Lee, L. Li, X. Li, R. Lindgren, N. Liyanage, H.J. Lu(Co-Sp), W. Luo, B.Q. Ma, S. Marrone, Z.-E. Meziani, B. Mot, P. Monaghan, N. Muangma, S. Nanda, V. Nelyubin, P.Z. Ning, B.E. Norum (Co-Sp), Y. Oh, A. Pucket, Y. Qing, O. Rondon-Aramayo, A. Saha, B. Sawatzky, S. Sirca, K.Slifer, L.C. Smith, J. Song, L. Tang, K. Wang (Co-Sp), X. Wang, L. Weinstein, B. Wojtsekhowski, G.M. Urciuoli, Y. Xu, X.H. Yan, H.Y. Yang, Y.X. Ye, Z. Ye, C.X. Yu, L. Yuan, X.-H. Zhan, X.D. Zhang, Y. Zhang, X. Zheng, S.H. Zhou,

Outline Semi-inclusive DIS hadron production at JLab Motivation -- Formation Length -- Attenuation -- Pt broadening Theory models Previous data Proposal at JLab 12GeV X

Semi-inclusive DIS hadron production X SIDIS: ep->e’+h+X, where h= , K,

Illustration of different steps in SIDIS Evolution of the struct partonenergy changed changed too large

EMC effect: Nuclear DIS structure function is not the same as D ! : Mass Number SIDIS in nucleus Structure function of a nucleon inside a nucleus is different to the one from the “bare” nucleon.

String Model: Confinement between quarks of a string Rescaling of fragmentation functions in nuclei: Based on EMC-effect. Bialas Model: Without involving the detail of internal physics. Probability for a hadronic fragment:is chacteristic time Kopeliovich Model: gluon bremsstrahlung. Only leading hadrons are considered Nuclear attenuation is mainly caused by induced gluon radiation and multiple parton scattering. Wang Model: Theroy models: Parton energy loss is calculated as twist-4 contributions to FF Treats pions and nucleons equally

Attenuation: Pt Broadening: Approaches Formation length:

Recent Data(from HERMES):

Previous Data: The largest A:131 Xe Q2: Need a larger A:stronger attenuation Need higher Q2: DIS dominating and factorization Need different v’s and Q2’s to check the effects Propose to study hadronization at JLab 12GeV with 2D, 12C, 64Cu, 184W at different kinematic settings

Detector Description

Proposal at JLab 12GeV Kinematic setting: W>2, x>0.2 Angle of hadron  h >5.5 o : 5 sets of (v,Q2) Electron scattering angle  e Hadron angle  h Target: 2D, 12C, 64Cu, 184W Phase space Cu C W Attenuation vs. v Curve a,b,c: bialas prediction for different target Red:simulation result for pi+ at z=0.65 Blue: HERMES data at z>0.5 Beam --- Energy: 11GeV --- Current: 100  A Hall C HMS and SHMS

Summary Proposal to study Hadronization at JLab 12GeV --- Kinematic setting selection --- Attenuation ( A, x, z, v, Q2) --- Pt broadening ( A, x, z, v, Q2)

GDH sum rule at very low Q2

Inclusive electron scattering Motivation: How do the constituents contribute to the nucleon properties? -- Cross section -- generalized GDH integral Previous data Proposal at JLab 12GeV -- Cross section asymmetry -- g1,g2

Inclusive Electron Scattering Structure functions: F1(x,Q 2 ), F2(x,Q 2 ) Unpolarized Cross Section:

Inclusive Electron Scattering Structure functions: F1(x,Q 2 ), F2(x,Q 2 ) Polarized Cross Section: Spin-dependent Structure functions: g1(x,Q 2 ), g2(x,Q 2 ) : Beam spin: Target spin

Sum Rule Bjorken Sum Rule( ): : nucleon axial charge Gerasimov-Drell-Hearn(GDH) Sum Rule( ): : Photo-absorption cross section with photon helicity (anti-)parallel to target spin : anomalous magnetic moment Generalized GDH Sum Rule( ): GDH Sum Rule Bjorken Sum Rule

Generalized GDH Sum Rule Generalized GDH Sum Rule( ): MAID Model: Include Resonance contributions A bridge connect pQCD and npQCD 3He target

Experimental Setup

---  is forward angle. --- spectrometer angle > 12.5 o add a septum magnet to bend the outgoing electron into the HRS  = 6 o, 9 o septum magnet at very low Q 2 Beam polarization: 74.8%

Polarized 3He Target Target polarization: about 40% Target: 3He + N2(1%) quench the photon emission Target Cell: ---Standard Cell: about 40cm ---Ice cone Cell: about 34cm for low energy events at 6 0 for high energy events and events at 9 o to reduce energy loss Should be subtracted as dilution effect

Approaches Unpolarized Cross Section Polarized cross section difference : Events accepted : Lifetime correction : Total charge ±: beam helicity :dilution factor:beam(target) polarization

Approaches Unpolarized Cross Section Polarized cross section difference g1,g2: Events accepted : Lifetime correction : Total charge ±: beam helicity :dilution factor:beam(target) polarization

Analysis flow

Preliminary Results g1,g2, GDH sum rule

Summary Generalized GDH sum rule could be measured at very low Q 2 Extrapolate to the real photon point: GDH sum rule Spin structure function g1 and g2 could be measured Thank all