Thesis

Systematic study of hyperon properties in finite and infinite nuclear systems: consequencies for neutron stars

• Call:

  IDPASC Portugal - PHD Programme 2016

• Academic Year:

  2016 / 2017

• Domains:

  Theoretical Particle Physics | Astrophysics

• Supervisor:

  Isaac Vidaña

• Co-Supervisor:

• Institution:

  Universidade de Coimbra

• Host Institution:

  CFisUC

• Abstract:

  Strangeness adds a new dimension to the evolving picture of nuclear physics giving us an opportunity to study the fundamental baryon-baryon interactions from an enlarged perspective. The presence of hyperons in infinite (hypernuclear matter and neutron star matter) and finite (hypernuclei) nuclear systems constitutes a unique probe of the deep nuclear interior which makes possible the study of a variety of otherwise inaccessible nuclear phenomena, and, thereby, to test nuclear models. Furtheremore, there is a growing evidence that strange particles can have significant implications for astrophysics. In particular, the presence of hyperons in the dense inner core of neutron stars is expected to have important consequences on the equation of state, structure and evolution of these compact objects. In this project we will study the properties of hyperons in infinite matter and hypernuclei. Our final scope is to relate hypernuclear and neutron star observables to the bare hyperon-nucleon and hyperon-hyperon interactions which, unfortunately, are not yet well constrained experimentally. To that end we will extend both microscopic and phenomenological approaches, usually used in the study of the properties of infinite nuclear matter and ordinary nuclei, to the hyperonic sector. The general scope of this project is the study of the properties of hyperons in infinite (hypernuclear matter and neutron star matter) and finite (hypernuclei) nuclear systems by extending both microscopic and phenomenological approaches that are commonly used in the studies of the properties of infinite nuclear matter and ordinary nuclei. Our final goal is to relate hypernuclear and neutron star observables to the bare hyperon-nucleon (YN) and hyperon-hyperon (YY) interactions. The experimental difficulties associated with the short lifetime of hyperons and low intensity beam fluxes have limited the number of YN scattering events to less than one thousand, not enough to fully constrain the YN interaction. In addition, there is no data at all on the YY scattering. In the absence of such data, alternative information on the YN and YY interactions can be obtained from the study of hypernuclei and the properties of hyperons in neutron stars. Specific objectives are: 1) Develop energy density functionals of hypernuclear matter starting from the most realistic NN, YN and YN interactions and study the consequences of hyperons in neutron stars paying special attention to the possible existence of a hyperon phase transition in the neutron star interior and the influence on it of the different terms of the functionals. 2) Extension of the Dirac-Brueckner-Hartree-Fock theory of nuclear matter to the hypernuclear matter case. 3) Systematic microscopic and phenomenological study of single- and double-? hypernuclei. Key words: Hyperons, hypernuclei, hyperon-nucleon and hyperon-hyperon interactions, compact stars.