{eta}{yields}{gamma}{gamma} Decay Width via the Primakoff Cross Section
- Physics Institute, University of Sao Paulo, P. O. Box 66318, CEP 05315-970, Sao Paulo (Brazil)
- Department of Physics and Biophysics, UNESP, Botucatu (Brazil)
- Center of Applied Studies for Nuclear Developments (CEADEN), Havana (Cuba)
- Department of Physics, Idaho State University, Pocatello Idaho, 83209 (United States)
- RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)
Incoherent {eta} photoproduction in nuclei is evaluated at forward angles within 4 to 9 GeV using a multiple scattering Monte Carlo cascade calculation with full {eta}-nucleus final-state interactions. The Primakoff, nuclear coherent and nuclear incoherent components of the cross sections fit remarkably well previous measurements for Be and Cu from Cornell, suggesting a destructive interference between the Coulomb and nuclear coherent amplitudes for Cu. The inelastic background of the data is consistently attributed to the nuclear incoherent part, which is clearly not isotropic as previously considered in Cornell's analysis. The respective Primakoff cross sections from Be and Cu give {gamma}{sub {eta}}{sub {yields}}{sub {gamma}}{sub {gamma}}=0.476(62) keV, where the quoted error is only statistical. This result is consistent with the Particle Data Group average of 0.510(26) keV and in sharp contrast ({approx}50%) with the value of 0.324(46) keV obtained at Cornell.
- OSTI ID:
- 21134090
- Journal Information:
- Physical Review Letters, Vol. 101, Issue 1; Other Information: DOI: 10.1103/PhysRevLett.101.012301; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
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