**Hadrons
In a Cold Nuclear Medium**,
T. Rodrigues, *Physics Institute - USP,
Brazil*
− The
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.

[1]
I. Larin et al.,
Phys. Rev. Lett. **106**,
162303 (2011).

[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).