Total hadronic photoabsorption cross-section on nuclei in the nucleon resonance region
Sep, 1995
38 pages
Published in:
- Phys.Rev.C 54 (1996) 1688-1699
Report number:
- LNF-95-053-P
Citations per year
Abstract: (APS)
The total photoabsorption cross section for Li7, C, Al, Cu, Sn, Pb has been measured in the energy range 300–1200 MeV at Frascati with the jet-target tagged photon beam. A 4π NaI crystal detector and a lead-glass shower counter were used, respectively, to measure hadronic events and to reject the electromagnetic background. Data above 600 MeV clearly indicate a broadening of higher nucleon resonance peaks in nuclei and a reduction of the absolute value of the cross section per nucleon with respect to the free-nucleon case. This large broadening suggests a strong influence of the nuclear medium in the resonance propagation and interaction, while the systematic reduction of the measured cross sections might be due to a depletion of the resonance excitation strength and to the onset of the shadowing effect around 1 GeV. Moreover, our systematic study indicates that also the Δ-resonance excitation parameters are not the same for all nuclei, being its mass and width increasing with the nuclear density. © 1996 The American Physical Society.- photon nucleus: nuclear reaction
- photon: tagged beam
- tagged beam: photon
- jet: target
- target: jet
- hadron: photoproduction
- photoproduction: hadron
- photon: absorption
- absorption: photon
- dependence: mass number
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