Charge-symmetry breaking in np elastic scattering at 477 MeV

Journal Article · Mon May 01 04:00:00 EDT 1989 · Phys. Rev. D; (United States)

DOI:https://doi.org/10.1103/PhysRevD.39.2464· OSTI ID:6320228

Abegg, R; Bandyopadhyay, D; Birchall, J; Cairns, E B; Coombes, G H; Davis, C A; Davison, N E; Delheij, P P.J.; Green, P W; Greeniaus, L G; others, and

The effect of isospin-violating, charge-symmetry-breaking (CSB) terms in the np interaction has been observed at TRIUMF by measuring the difference in the zero-crossing angles of the neutron and proton analyzing powers, A/sub n/ and A/sub p/, at a neutron energy of 477 MeV. The scattering asymmetries were measured with a neutron beam incident on a polarizable proton target. To reduce systematic errors, interleaved measurements of A/sub n/ and A/sub p/ were made using the same beam and target (apart from their respective polarization states). Neutrons and protons were detected in coincidence in the center-of-mass angle range from 59/sup 0/--80/sup 0/. The difference in zero-crossing angles was 0.340/sup 0/ +- 0.162/sup 0/ ( +- 0.058/sup 0/), which yields ..delta..AequivalentA/sub n/-A/sub p/ = 0.0047 +- 0.0022 ( +- 0.0008) using dA/dtheta/sub c.m./ = -0.013 82 deg/sup -1/. The second errors represent systematic effects. This result is in good agreement with recent theoretical calculations which include CSB effects due to the np mass difference in ..pi.., rho, and 2..pi.. exchange, electromagnetic coupling of the neutron anomalous magnetic moment to the proton current, rho-..omega..-meson mixing, and short- and medium-range effects of the up- and down-quark mass difference.

• Research Organization: TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3 University of Manitoba, Department of Physics, Winnipeg, Manitoba, Canada R3T 2N2 University of Alberta, Department of Physics, Edmonton, Alberta, Canada T6G 2N5 Instituet fuer Physik, Universitaet Basel, CH-4056 Basel, Switzerland
• OSTI ID: 6320228
• Journal Information: Phys. Rev. D; (United States), Journal Name: Phys. Rev. D; (United States) Vol. 39:9; ISSN PRVDA
• Country of Publication: United States
• Language: English

Related Subjects

645103* -- High Energy Physics-- Particle Interactions & Properties-Experimental-- Strong Interactions & Baryon & Meson Properties
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ACCELERATORS
ANALYZING POWER
BARYON-BARYON INTERACTIONS
BOSON-EXCHANGE MODELS
CHARGE DISTRIBUTION
COINCIDENCE SPECTROMETRY
CYCLIC ACCELERATORS
CYCLOTRONS
ELASTIC SCATTERING
ELEMENTARY PARTICLES
ENERGY RANGE
HADRON-HADRON INTERACTIONS
HAMILTONIANS
INTERACTIONS
INVARIANCE PRINCIPLES
ISOCHRONOUS CYCLOTRONS
ISOSPIN
LORENTZ INVARIANCE
MAGNETIC MOMENTS
MASS DIFFERENCE
MATHEMATICAL MODELS
MATHEMATICAL OPERATORS
MEV RANGE
MEV RANGE 100-1000
NUCLEON-NUCLEON INTERACTIONS
OBE MODEL
PARTICLE INTERACTIONS
PARTICLE MODELS
PARTICLE PROPERTIES
PERIPHERAL MODELS
POSTULATED PARTICLES
PROTON-NEUTRON INTERACTIONS
PROTON-NUCLEON INTERACTIONS
QUANTUM OPERATORS
QUARKS
SCATTERING
SYMMETRY BREAKING
TRIUMF CYCLOTRON