A fase supercondutora de cor da matéria estranha no modelo cromodielétrico e estrelas de Quarks

• Ano de defesa: 2005
• Autor(a) principal: Linares, Luis Paulo Fernandes Liberto
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Programa de Pós-graduação em Física; Física
• Palavras-chave em Português: Modelo cromodielétrico; Matéria estranha; Quarks; CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA
• Link de acesso: https://app.uff.br/riuff/handle/1/19167

Recent results obtained in the Chromodielectric model (CDM) show that strange quark matter at very high densities may appear in two phases, namely a chiral broken and a chiral symmetric phase, which may be not absolutely stable. At high densities, the abundance of quarks u, d and s are the same in the chiral symmetric phase and there are no electrons. These two properties are also obtained in a new phase which is expected to occur in QCD at very high densities, known as color flavor locked (CFL) phase. This suggests that strange matter can make a transition to the CFL phase, in which the energy is lowered by the quark BCS pairing. It is now generally believed that the CFL state (at least for asymptotic densities) is likely to be the ground state even for different quark masses. In this thesis we perform a study in an extended version of the Chromodielectric model (CDM) with the BCS quark pairing implemented, and analyze the superconducting color flavor locked phase. In the CDM there is a confining potential which originates a bag constant B. We show that the inclusion in the free energy density of a negative term of the diquark condensate keeps the stability of quark matter even for a large potential energy. The reason for that is because when the gap energy of the QCD Cooper pairs increases, the confining potential energy can also increase and the strange matter still remains absolutely stable (i.e., its energy per particle lies bellow the nucleon mass). We investigated the phase transition among the equations of state and conclude that at high densities the color superconducting phase cannot make a transition to the strange unpaired quark matter. So the the CFL state is the real ground state of strange quark matter in the CDM model. This study is also relevant for astrophysics in particular for understanding the formation and structure of compact quark stars. We explicitly show that CFL stars can be absolutely stable and even more compact than strange stars.