Dissertação
O áxion em condições extremas: matéria de quarks quente e magnetizada, meios densos e estrelas compactas
Fecha
2023-07-31Autor
Lopes, Bruno da Silva
Institución
Resumen
We investigate the phase diagram of quantum chromodynamics by means of the Nambu-
Jona-Lasinio effective model, including the axion - a particle which emerges as a solution
of the strong charge-parity (CP) problem and may describe dark matter - contributions. Initially
we study quark matter in a hot and magnetized medium, observing their effects on the
mechanisms of chiral symmetry and charge-parity spontaneous breaking and restoration.
We also verify the magnetic catalysis and inverse magnetic catalysis phenomena via a medium
dependent coupling, and calculate quantities related to the axion such as it’s mass
and self-coupling. Afterwards, we verify the effects of finite density in the NJL model with
the goal of applying it to the study of hybrid stars, composed by a hadronic crust and deconfined
quark matter at it’s core. For purposes of generalization of our results, two hadron
models are considered. We find that the axion presence helps maintaining the stability of
hybrid neutron stars, by weakening the transition between phases and bringing it to lower
densities. As such, the results satisfy the constraints coming from gravitational wave detections
and pulsar observations.