Goldstone Boson Condensation and Effects of the Axial Anomaly in Color Superconductivity

• Main Author: Basler, Hannes
• Format: Others
• Language: English; en
• Published: 2011
• Online Access: https://tuprints.ulb.tu-darmstadt.de/2399/1/Thesis_Basler.pdf; Basler, Hannes <http://tuprints.ulb.tu-darmstadt.de/view/person/Basler=3AHannes=3A=3A.html> (2011): Goldstone Boson Condensation and Effects of the Axial Anomaly in Color Superconductivity.Darmstadt, Technische Universität, [Ph.D. Thesis]

One of the central objects of interest in high energy physics is the phase diagram of strongly interacting matter, the behavior of quarks and gluons in dependence of temperature and chemical potential. At very high densities and low temperatures it is expected that quarks form a superconductor, the so-called color superconductor. Such a color superconductor might be realized in the inner core of a neutron star. To study the phase structure of a color superconductor under neutron star conditions the Nambu-Jona-Lasinio model is used. The diquark condensates appearing in a color superconductor may break the original symmetries and give rise to Goldstone bosons. In this work we study the possible condensation of these Goldstone bosons. On the level of diquark condensates the condensation of Goldstone bosons is realized by a rotation of scalar into pseudoscalar diquark condensates. The phase diagram is studied, including pseudoscalar diquark condensates, for several different values of the lepton number chemical potential. The masses and thereby the condensation of the Goldstone bosons is effected by a six-point interaction that breaks the axial U(1) symmetry. Usually this six-point interaction is implemented in the NJL model in such a way that is does not effect the diquark sector. This can be fixed by adding an second six-point interaction term to the NJL Lagrangian. The coupling strength of this new interaction term has a great influence on the phase digram. In this context also the effect on the chiral phase transition is studied.