Pion and nucleon structure as probed in the reaction. pi. /sup +-/N. -->. mu. /sup +/. mu. /sup -/X at 253 GeV
New results are presented from Fermilab experiment E615, in which hadroproduction of muon pairs allows a determination of the quark structure of the initial-state hadrons in the context of a Drell-Yan model. Comparison of muon-pair production by ..pi../sup +/ and ..pi../sup -/ beams shows the cross-section ratio follows Drell-Yan model expectations, except for a dip in sigma(..pi../sup +/)/sigma(..pi../sup -/) near x/sub ..pi../ near 1. The same data are also used to extract the ratio of the sea to valence quark distributions in the nucleon, with improved accuracy for x/sub N/ < 0.1 compared to deep-inelastic neutrino scattering. The Drell-Yan analysis of continuum muon-pair production has been extended down to a mass of 3.2 GeV/c/sup 2/ for the ..pi../sup -/ data sample. This provides stronger evidence of a rise in the nucleon structure function for x/sub N/ < 0.06 compared to that extracted in deep-inelastic lepton scattering. The issue is raised of the nonuniqueness of the definition of x/sub ..pi../ and x/sub N/ used in the Drell-Yan analysis. A definition proposed by Soper has superior invariance properties to that commonly used. An analysis based on this definition yields generally similar results for the pion and nucleon structure function, compared to use of the common definition. However, the pion structure function shows a larger intercept at x/sub ..pi../ = 1 when the definition of Soper is used. 21 refs., 6 figs.
- Research Organization:
- Princeton Univ., NJ (USA). Joseph Henry Labs.
- DOE Contract Number:
- AC02-76ER03072
- OSTI ID:
- 6554512
- Report Number(s):
- DOE/ER/03072-47; CONF-8809224-1; ON: DE89003669
- Country of Publication:
- United States
- Language:
- English
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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BARYONS
BOSONS
CHARMONIUM
CROSS SECTIONS
DEEP INELASTIC SCATTERING
DRELL MODEL
ELEMENTARY PARTICLES
FERMIONS
FUNCTIONS
HADRON-HADRON INTERACTIONS
HADRONS
INELASTIC SCATTERING
INTERACTIONS
J PSI-3097 MESONS
LEPTON-BARYON INTERACTIONS
LEPTON-HADRON INTERACTIONS
LEPTON-NUCLEON INTERACTIONS
MESON-BARYON INTERACTIONS
MESON-NUCLEON INTERACTIONS
MESONS
MUON PAIRS
NUCLEONS
PAIR PRODUCTION
PARTICLE INTERACTIONS
PARTICLE STRUCTURE
PION-NUCLEON INTERACTIONS
PIONS
POSTULATED PARTICLES
PSEUDOSCALAR MESONS
QUARKONIUM
QUARKS
SCATTERING
STRUCTURE FUNCTIONS
VECTOR MESONS