Diffractive production of vector mesons in muon-proton scattering at 150 and 100 GeV

Journal Article · Thu Jul 01 04:00:00 EDT 1982 · Phys. Rev. D; (United States)

DOI:https://doi.org/10.1103/PhysRevD.26.1· OSTI ID:5019818

Shambroom, W D; Wilson, R; Gordon, B A

We have studied the production of rho and phi mesons from muon scattering on a liquid-hydrogen target at 150 and 100 GeV. For the rho we observe a skewed mass distribution which becomes somewhat more normal with increasing Q/sup 2/ (the square of the four-momentum transferred from the muon), and an exponential distribution in t (the square of the four-momentum transferred to the target proton) with a slope which is consistent with a slight decrease as Q/sup 2/ increases. The dependence of the cross section on Q/sup 2/ follows that of the square of the rho propagator with little contribution from longitudinal rho production. The angular distribution of the rho decay confirms the smallness of the contribution from longitudinal rho production at our energies. The cross section when extrapolated to Q/sup 2/ = 0 agrees with that measured in real photoproduction. The decay angular distribution of the rho decay shows that s-channel helicity is largely conserved, although we detect a helicity-single-flip contribution at the 10--15 % level. Natural-parity exchange in the t channel dominates, and the transverse and longitudinal amplitudes are found to be in phase. These characteristics are consistent with the diffractive nature of the vector-dominance model. The t distribution of phi production is also exponential, although less steep than that for the rho. We observe an elastically produced four-pion state at a mass of approximately 1600 MeV. We identify this state with the rho' (1600), and find it to be produced with a distribution exponential in t.

• Research Organization: Department of Physics, Harvard University, Cambridge, Massachusetts 02138
• OSTI ID: 5019818
• Journal Information: Phys. Rev. D; (United States), Journal Name: Phys. Rev. D; (United States) Vol. 26:1; ISSN PRVDA
• Country of Publication: United States
• Language: English

Related Subjects

645102* -- High Energy Physics-- Particle Interactions & Properties-Experimental-- Weak Interactions & Properties
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANGULAR DISTRIBUTION
BOSONS
CROSS SECTIONS
DIFFRACTION MODELS
DISTRIBUTION
ELASTIC SCATTERING
ELEMENTARY PARTICLES
ENERGY RANGE
GEV RANGE
GEV RANGE 100-1000
HADRONS
HELICITY
INTERACTIONS
LEPTON-BARYON INTERACTIONS
LEPTON-HADRON INTERACTIONS
LEPTON-NUCLEON INTERACTIONS
MATHEMATICAL MODELS
MESON RESONANCES
MESONS
MUON-NUCLEON INTERACTIONS
MUON-PROTON INTERACTIONS
PARTICLE INTERACTIONS
PARTICLE MODELS
PARTICLE PRODUCTION
PARTICLE PROPERTIES
PROPAGATOR
RESONANCE PARTICLES
SCATTERING
VECTOR MESONS