EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH CERN–TH/7216/94 April 1994 THE THEORY AND PHENOMENOLOGY OF POLARIZED DEEP INELASTIC SCATTERING

CONTENTS 1) Introduction 1.1) Notation 2) Polarized lepton-nucleon deep inelastic scattering – general aspects 2.1) General formalism in the one photon exchange approximation 2.1.1) Structure functions and Bjorken scaling 2.1.2) Cross-section differences 2.1.3) Experimental measurement of g 1 and g 2 on nucleon targets a) Longitudinally polarized target b) Transversely polarized target c) Combined analysis using both polarizations d) The problem of extrapolating in Q 2 2.1.4) Measurement of g 1,2 on nuclear targets 2.2) Neutral and charged current weak interactions initiated by charged leptons 2.2.1) Weak interaction structure functions and their measurement 3) The Naive Parton Model in polarized DIS 3.1) Projection of F 1,2 and g 1,2 from the hadronic tensor W µν 3.2) The hadronic tensor and the nucleon structure functions in the Naive Parton Model 3.3) Intrinsic p ⊥ and g 2 (x) 3.3.1) Conflicting Parton Model results for g 2 (x) 3.4) Origin of the difficulties with g 2 (x) 3.5) Weak interaction structure functions in the Naive Parton Model 4) Phenomenological analysis of the data on g 1 (x) and its first moment Γ 1 4.1) The SLAC-Yale and EMC data: quark distributions near x = 1 4.2) Analysis of data in the framework of the Operator Product Expansion 4.2.1) Information from hyperon β-decay 4.2.2) The EMC data on Γ p 1 and its consequences 4.2.3) The EMC data: extrapolation to x = 0 4.2.4) The EMC data: higher twist effects a) The Gerasimov, Drell, Hearn approach b) The QCD sum rule approach c) Summary on higher twist effects in the EMC experiment 4.3) The EMC result: implications in the Naive Parton Model 4.3.1) The 'Spin crisis in the Parton Model' 4.3.2) The angular momentum sum rule 4.3.3) Trouble with the strange quark 4.4) Analysis of Γ p 1 using the QCD Improved Parton Model 4.4.1) The Operator Product Expansion for Γ p 1 4.5) The new experiments: neutron data and the Bjorken sum rule 4.5.1) The new experiments on deuterium and 3 He 4.5.2) Tests of the Bjorken sum rule 5) The Operator Product Expansion (OPE) 5.1) General structure of the OPE 5.2) Equations for the moments of g 1,2 (x, Q 2) 5.3) Is there a connection between g 1 (x) and g 2 (x)? 5.4) Does the first moment of g 2 (x) vanish? (The Burkhardt-Cottingham sum rule) 5.5) The Efremov-Leader-Teryaev sum rule 6) g 1 (x): The axial anomaly and …