arXiv subjects

T. Falter

Publications and source records attributed to T. Falter.

21 records · Page 2Linked to original sources

arXiv2002

Formation time of hadrons in photon induced reactions on nuclei

We present a way to account for coherence length effects in a semi-classical transport model. This allows us to describe photo- and electroproduction at large nuclei (A>12) and high energies using a realistic coupled channel description of the final state interactions that goes far beyond simple Glauber theory. We show that the purely absorptive treatment of the final state interactions as usually done in simple Glauber theory might lead to wrong estimates of color transparency and formation time effects in particle production. As an example we discuss exclusive rho^0 photoproduction on Pb at a photon energy of 7 GeV as well as K^+ and K^- production on C and Pb in the photon energy range 1-7 GeV.

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arXiv2001

Nuclear shadowing at low photon energies

We calculate the shadowing effect in nuclear photoabsorption at low photon energies (1-3 GeV) within a multiple scattering approach. We avoid some of the high energy approximations that are usually made in simple Glauber theory like the narrow width and the eikonal approximation. We find that the main contribution to nuclear shadowing at low energies stems from $ρ^0$ mesons with masses well below their pole mass. We also show that the possibility of scattering in non forward directions allows for a new contribution to shadowing at low energies: the production of neutral pions as intermediate hadronic states enhances the shadowing effect in the onset region. For light nuclei and small photon energies they give rise to about 30% of the total shadowing effect.

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arXiv2000

Low energy onset of nuclear shadowing in photoabsorption

The early onset of nuclear shadowing in photoabsorption at low photon energies has recently been interpreted as a possible signature of a decrease of the rho meson mass in nuclei. We show that one can understand this early onset within simple Glauber theory if one takes the negative real part of the rho N scattering amplitudes into account, corresponding to a higher effective mass of the rho meson in nuclear medium.

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