Measurement of the internal spin structure of the nucleon

Conference · Mon May 01 04:00:00 EDT 1989 · AIP Conference Proceedings (American Institute of Physics) Conference Proceedings; (USA)

OSTI ID:5249047

Schuler, K P ^[1]

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1. Yale University, J. W. Gibbs Lab., New Haven, CT 06511 (US)

Recent measurements by the European Muon Collaboration of the spin-dependent structure function {ital g}{sup {ital p}}{sub {ital l}}({ital x}) of the proton indicate a significant voilation of the Ellis-Jaffe sum rule and imply an entirely unexpected composition of the spin of the proton in the context of the simple quark-parton model. Inclusion of older measurements from SLAC strengthens the EMC result. Based on the combined EMC and SLAC data, the individual quark flavors {ital u}+{ital {bar u}}, {ital d}+{ital {bar d}} and {ital s}+{ital {bar s}} are found to contribute, respectively, +(75{plus minus}6)% and {minus}(22{plus minus}6)% of the spin of the proton. All quarks combined account then only (2{plus minus}19)% of the spin of the proton, while the balance must be due to gluons and/or orbital angular momentum. Several groups have announced plans to measure both the proton and neutron spin-dependent structure functions with the aim to test the fundamental Bjorken sume rule. We discuss several of those possible future experiments.

• OSTI ID: 5249047
• Report Number(s): CONF-880983--
• Conference Information: Journal Name: AIP Conference Proceedings (American Institute of Physics) Conference Proceedings; (USA) Journal Volume: 187:1
• Country of Publication: United States
• Language: English

Related Subjects

645300* -- High Energy Physics-- Particle Invariance Principles & Symmetries
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANGULAR MOMENTUM
ASYMMETRY
BARYONS
DATA
ELEMENTARY PARTICLES
EMC EFFECT
EQUATIONS
EXPERIMENT PLANNING
EXPERIMENTAL DATA
FERMIONS
FUNCTIONS
HADRONS
INFORMATION
INTERACTIONS
LEPTON-BARYON INTERACTIONS
LEPTON-HADRON INTERACTIONS
LEPTON-NUCLEON INTERACTIONS
MUON-NUCLEON INTERACTIONS
MUON-PROTON INTERACTIONS
NUCLEONS
NUMERICAL DATA
PARTICLE INTERACTIONS
PARTICLE PROPERTIES
PLANNING
SPIN
STRUCTURE FUNCTIONS
SUM RULES