Measurement of the internal spin structure of the nucleon
- 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-; CODEN: APCPC; TRN: 90-000066
- Journal Information:
- AIP Conference Proceedings (American Institute of Physics) Conference Proceedings; (USA), Vol. 187:1; Conference: 8. international symposium on high energy spin physics, Minneapolis, MN (USA), 12-17 Sep 1988; ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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NUCLEONS
SPIN
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EXPERIMENT PLANNING
EXPERIMENTAL DATA
MUON-PROTON INTERACTIONS
STRUCTURE FUNCTIONS
SUM RULES
ANGULAR MOMENTUM
BARYONS
DATA
ELEMENTARY PARTICLES
EQUATIONS
FERMIONS
FUNCTIONS
HADRONS
INFORMATION
INTERACTIONS
LEPTON-BARYON INTERACTIONS
LEPTON-HADRON INTERACTIONS
LEPTON-NUCLEON INTERACTIONS
MUON-NUCLEON INTERACTIONS
NUMERICAL DATA
PARTICLE INTERACTIONS
PARTICLE PROPERTIES
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