Seminarium "Teoria cząstek elementarnych i kosmologia"

In this talk I will focus on the study of the vacuum dynamics of pseudo-Nambu-Goldstone bosons (pNGBs) for SO(N+1) —> SO(N) spontaneous and explicit symmetry breaking. I will show how to determine the magnitude of explicit symmetry breaking consistently with an EFT description of the effective potential at zero and finite temperatures. Given that, I will expose and clarify novel additional vacuum transitions that can arise for generic pNGBs below the initial scale of SO(N+1) —> SO(N) spontaneous symmetry breaking, which may have phenomenological relevance. In this respect, two phenomenological scenarios are analyzed: thermal and supercooled dark sector pNGBs. In the thermal scenario the vacuum transition is first-order but very weak. For a supercooled dark sector we find that, depending on the sign of the explicit symmetry breaking, one can have a symmetry-restoring vacuum transition SO(N-1) —> SO(N) which can be strongly first-order, with a detectable stochastic gravitational wave background signal.

slides: https://mycloud.fuw.edu.pl/index.php/s/q2pCCCQkiJk2Dim