Measurement of isospin mixing in /sup 4/He and its implications for charge-symmetry breaking

Journal Article · Mon Aug 04 04:00:00 EDT 1986 · Phys. Rev. Lett.; (United States)

DOI:https://doi.org/10.1103/PhysRevLett.57.543· OSTI ID:5135142

Blilie, C L; Dehnhard, D; Holtkamp, D B; Cottingame, W B; Halderson, D; Morris, C L; Moore, C F; Seidl, P A; Ohnuma, H; Maeda, K

..pi..-/sup 4/He inelastic cross sections have been measured at T/sub ..pi../ = 180 MeV. In the region of the J/sup ..pi../ = 1/sup -/ states (E/sub x/approx. =23 to 30 MeV) the ..pi../sup +//..pi../sup -/ cross-section ratio R/sub ..pi../ was found to be 1.05 +- 0.08 at theta/sub lab/ = 30/sup 0/. Such a small deviation from 1.0 implies that isospin mixing between the T = 0 and T = 1 states in /sup 4/He is quite weak, in striking contrast to the strong isospin mixing deduced from the large ratio of photonucleon cross sections, R/sub ..gamma../ = sigma(..gamma..,p)/sigma(..gamma..,n)approx. =1.7. Thus the conclusion drawn from the photonucleon work, that there is a large charge-symmetry-breaking nuclear force in /sup 4/He, needs to be reexamined.

• Research Organization: School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455
• OSTI ID: 5135142
• Journal Information: Phys. Rev. Lett.; (United States), Journal Name: Phys. Rev. Lett.; (United States) Vol. 57:5; ISSN PRLTA
• Country of Publication: United States
• Language: English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR DISTRIBUTION
ANGULAR MOMENTUM
BARYONS
CHARGE DISTRIBUTION
CHARGED-PARTICLE REACTIONS
CROSS SECTIONS
DATA
DISTRIBUTION
ELEMENTARY PARTICLES
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EVEN-EVEN NUCLEI
EXPERIMENTAL DATA
FERMIONS
HADRON REACTIONS
HADRONS
HELIUM 4
HELIUM 4 TARGET
HELIUM ISOTOPES
INELASTIC SCATTERING
INFORMATION
ISOSPIN
ISOTOPES
LIGHT NUCLEI
MESON REACTIONS
MEV RANGE
MEV RANGE 100-1000
NUCLEAR FORCES
NUCLEAR REACTIONS
NUCLEI
NUCLEONS
NUMERICAL DATA
PARITY
PARTICLE PROPERTIES
PHOTONUCLEONS
PION MINUS REACTIONS
PION PLUS REACTIONS
PION REACTIONS
SCATTERING
SPIN
STABLE ISOTOPES
SYMMETRY BREAKING
TARGETS