Cosmological Evolution of Glueball Dark Matter in Dark Yang-Mills Sectors

Sammanfattning

This thesis investigates the possibility of dark matter arising from a confining dark SU(N) Yang-Mills sector with N=3,4,5. First, standard results from the established single-scalar-glueball framework are reviewed and numerically reproduced in order to follow the cosmological evolution through the confinement phase transition and extract the relic abundance. The results reproduce the expected qualitative behaviour for the relic abundance which shows that glueballs could account for the totality of dark matter. The analysis is then extended at an exploratory level to a two-glueball effective theory which contains scalar and pseudoscalar degrees of freedom. For this two-field case, coupled equations of motion are solved for benchmark parameter choices. Since the two-field temperature potential is not yet lattice calibrated, and since the late-time oscillatory regime is numerically stiff, the calculations are not yet precise relic-density predictions. Instead, the two-field result should be interpreted as diagnostic evidence for the qualitative dynamics of coupled glueball dark matter and as motivation for improved numerical treatment.