Searching for P-odd effects in heavy ion collisions

We investigate how local parity breaking due to large topological
fluctuations may affect hadron physics in heavy ion collisions.
A distorted dispersion relation can derived for the lightest
vector mesons ω and ρ leading to characteristic mass splittings
depending on their polarization. We present an analysis of the
corresponding angular distribution associated to the lepton pairs
as an unambiguous way of detecting such a striking phenomenon.
We also investigate how other light mesons may be influenced by parity
breaking by means of an effective lagrangian. We speculate whether
this phenomenon may be the cause of the long-standing problem with
the dilepton excess at low invariant masses. The phase diagram
is investigated using a simplified Nambu-Jona-Lasinio model and a
rich structure is found. Finally, a bottom-up holographic model is
constructed allowing to predict how the whole QCD spectrum could be
modified in the presence of local parity breaking.