Hadrons In a Cold Nuclear Medium, T. Rodrigues, Physics Institute - USP,  BrazilThe breaking of the chiral symmetry of QCD that leads to the anomalous radiative decay of pseudoscalar mesons can be explored in photoproduction experiments as recently performed by the PrimEx Collaboration at the Jefferson Laboratory (JLab) [1].  The modification of vector meson properties (masses/widths) due to a partial restoration of chiral symmetry can also be investigated via the study of nuclear transparencies, as proposed by the CBELSA/TAPS [2] and CLAS [3] Collaborations.  All these measurements have a common issue since they depend on the nuclear models that describe the mechanism of incoherent photoproduction.  In this talk, we present calculations for the incoherent cross section based on the Monte Carlo Multi-Collisional (MCMC) intranuclear cascade model [4-6].  Our results for omega photoproduction [6] show that the CBELSA/TAPS measurements [2] are consistent with an in-medium width of approximately 30 MeV and in-medium omega-nucleon cross section within 25 to 30 mb.  These results are in sharp contrast with the Glauber model, as well as the predictions from the Giessen [7] and Valencia [8] theory groups.  The potentialities of the MCMC model to describe the hadronic phase of heavy-ion collisions will also be addressed.


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[2] M. Kotulla et al., Phys. Rev. Lett. 100, 192302 (2008).

[3] M. H. Wood et al., Phys. Rev. Lett. 105, 112301 (2010).

[4] T. E. Rodrigues et al., Phys. Rev. Lett. 101, 012301 (2008).

[5] T. E. Rodrigues et al., Phys. Rev. C 82, 024608 (2010).

[6] T. E. Rodrigues and J. D. T. Arruda-Neto, Phys. Rev. C 84, 021601(R) (2011).

[7] P. Mühlich and U. Mosel, Nucl. Phys. A 773, 156 (2006).

[8] M. Kaskulov, E. Hernandez, and E. Oset, Eur. Phys. J. A 31, 245 (2007).