Open AccessSource Theory Discussion of Deep Inelastic Scattering with Polarized Particles
Author(s) -
Julian Schwinger
Publication year - 1975
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.72.4.1559
Subject(s) - physics , sum rule in quantum mechanics , deep inelastic scattering , inelastic scattering , virtual particle , nucleon , photon , helicity , scattering , photon polarization , omega , electron , particle physics , muon , atomic physics , quantum mechanics , quantum chromodynamics
A general phenomenological framework is provided for the discussion of the inelastic scattering of polarized electrons (muons) on polarized nucleons, when regarded as the absorption of polarized virtual photons. The relevant cross sections compare parallel and antiparallel orientations of the photon helicity and nucleon spin, and also deal with linear combinations of longitudinal and transverse polarization. The polarization asymmetry for transverse polarization,P , assumes a scaling form in the deep inelastic scattering region, and should go to zero as ω-1 for large ω. The latter behavior is connected, through the use of the improved scaling variable ωs , with the high energy real photon situation. A sum rule is exhibited which implies thatP must change sign in the deep inelastic region. This sum rule also yields the known Drell-Hearn sum rule for real photon Compton scattering, when combined with another, new, sum rule for the anomalous magnetic moment. The latter is verified in the context of pure electrodynamics to the lowest order in α. Finally, it is conjectured thatP specifically changes from negative to positive values as ω varies from 1 to ∞.