Nuclear incoherent photoproduction of {pi}{sup 0} and {eta} from 4 to 12 GeV

Journal Article · Sun Aug 15 00:00:00 EDT 2010 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.82.024608· OSTI ID:21419441

Rodrigues, T E ^[1]; Arruda-Neto, J D. T. ^[1]; Mesa, J ^[2]; Garcia, C ^[3]; Shtejer, K ^[1]; Dale, D; Cole, P L ^[4]; Nakagawa, I ^[5]

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1. Physics Institute, University of Sao Paulo, P.O. Box 66318, CEP 05315-970, Sao Paulo (Brazil)
2. Department of Physics and Biophysics, UNESP, Botucatu (Brazil)
3. Center of Applied Studies for Nuclear Developments (CEADEN), Havana (Cuba)
4. Department of Physics, Idaho State University, Pocatello, Idaho 83209 (United States)
5. RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

The mechanism of incoherent {pi}{sup 0} and {eta} photoproduction from complex nuclei is investigated from 4 to 12 GeV with an extended version of the multicollisional Monte Carlo (MCMC) intranuclear cascade model. The calculations take into account the elementary photoproduction amplitudes via a Regge model and the nuclear effects of photon shadowing, Pauli blocking, and meson-nucleus final-state interactions. The results for {pi}{sup 0} photoproduction reproduced for the first time the magnitude and energy dependence of the measured rations {sigma}{sub {gamma}A}/{sigma}{sub {gamma}N} for several nuclei (Be, C, Al, Cu, Ag, and Pb) from a Cornell experiment. The results for {eta} photoproduction fitted the inelastic background in Cornell's yields remarkably well, which is clearly not isotropic as previously considered in Cornell's analysis. With this constraint for the background, the {eta}{yields}{gamma}{gamma} decay width was extracted using the Primakoff method, combining Be and Cu data [{Gamma}{sub {eta}{yields}{gamma}{gamma}=}0.476(62) keV] and using Be data only [{Gamma}{sub {eta}{yields}{gamma}{gamma}=}0.512(90) keV]; where the errors are only statistical. These results are in sharp contrast ({approx}50-60%) with the value reported by the Cornell group [{Gamma}{sub {eta}{yields}{gamma}{gamma}=}0.324(46) keV] and in line with the Particle Data Group average of 0.510(26) keV.

• OSTI ID: 21419441
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 82, Issue 2; Other Information: DOI: 10.1103/PhysRevC.82.024608; (c) 2010 The American Physical Society; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALUMINIUM
BERYLLIUM
CARBON
COPPER
ENERGY DEPENDENCE
ETA MESONS
FINAL-STATE INTERACTIONS
GAMMA DECAY
GEV RANGE
LEAD
MONTE CARLO METHOD
NUCLEAR CASCADES
NUCLEI
PARTICLE PRODUCTION
PHOTONS
PHOTOPRODUCTION
PIONS NEUTRAL
REGGE CALCULUS
SILVER
SIMULATION
ALKALINE EARTH METALS
BASIC INTERACTIONS
BOSONS
CALCULATION METHODS
DECAY
ELECTROMAGNETIC INTERACTIONS
ELEMENTARY PARTICLES
ELEMENTS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
HADRONS
INTERACTIONS
MASSLESS PARTICLES
MESONS
METALS
NONMETALS
NUCLEAR DECAY
PARTICLE INTERACTIONS
PIONS
PSEUDOSCALAR MESONS
TRANSITION ELEMENTS