Photoproduction of mesons in nuclei at GeV energies

Abstract

In a transport model that combines initial state interactions of the photon with final state interactions of the produced particles we present a calculation of inclusive photoproduction of mesons in nuclei in the energy range from 1 to 7 GeV. We give predictions for the photoproduction cross sections of pions, etas, kaons, antikaons, and $\pi^+\pi^-$ invariant mass spectra in ^{12}C and ^{208}Pb. The effects of nuclear shadowing and final state interaction of the produced particles are discussed in detail.Comment: Text added in summary in general reliability of the method, references updated. Phys. Rev. C (2000) in pres

Hadron properties in the nuclear medium

“…(right) Result of the fits to the e + e − invariant mass spectrum obtained for the 2 H (top), C (middle), and Fe-Ti (bottom) data (Wood et al, 2008). The curves on the right panels are Monte-Carlo calculations by the BUU model for various vector meson decay channels (Effenberger et al, 1999;Effenberger and Mosel, 2000). mass spectra.…”

In-medium properties of hadrons—observables

“…Shown on the left are results of a calculation that uses only a shift of the pole mass of the vector mesons. On the right, results are given for a calculation using both mass shift and collisional broadening (from [28]). …”

“…In an interaction with a bound nucleon the shadowed incoming photon then produces a hadronic final state which cascades through the nucleus [28,29]. The incoherent final state interactions are treated as just described by means of a semi-classical coupled-channel transport theory.…”

Experimental study of hadron properties in the nuclear medium

“…3c shows the Fe-Ti result after combinatorial background subtraction. Curves are Monte Carlo calculations by the BUU model [34,35] for various e + e − channels. Contrary to the E325 result, there is no appreciable excess.…”