## Seminar on Theoretical Nuclear Physics

## 19.06.12 16:15

# Baryons at high density and the role of the dilaton

## Chihiro Sasaki (Frankfurt)

Abstract:

In nuclear physics, a scalar meson plays an essential role as known from Walecka model that works fairly well for phenomena near nuclear matter density. On the other hand, at high density, the relevant Lagrangian which has the correct symmetry is the linear sigma model, and the scalar needed there is the sigma that is the 4th component of the chiral 4-vector. Thus, in order to probe highly dense matter, we have to figure out how the chiral scalar at low density transmutes to the 4th component of the 4-vector.

In this seminar, we introduce a chiral scalar as a dilaton associated with broken conformal symmetry and responsible for the trace anomaly in QCD. As the "dilaton limit" is taken, which drives a system from nuclear matter density to near chiral restoration density, a linear sigma model emerges from the highly non-linear structure with the omega meson decoupling from the nucleons. We discuss its phenomenological implications at high density.