Seminário 03/09 - sexta-feira

Na próxima sexta-feira, dia 03/09 às 10:00h, teremos o Seminário de Enrico D. Schiappacasse (Universidade de Jyvaskyla & Instituto de Física de Helsinki, Finlândia) intitulado: "On Axion Stars and Primordial Black Holes"


Contamos com a presença de todos!

Título: On Axion Stars and Primordial Black Holes

Resumo: The axion is one of the strongest dark matter (DM) candidates by considering shortcomings in the Standard Model of particle physics. However, the scenario in which the axion is accompanied by a small fraction of primordial black holes (PBHs) is probable.  PBHs not only are one of the oldest dark matter candidates, but also, the possibility of their existence has been strongly revitalized in recent years after LIGO-Virgo gravitational waves detection.  In this mixed dark matter scenario, PBHs will naturally act as seeds leading to the formation of axion dark mini-halos around them.  In this talk, I will first review main properties of gravitationally bound clumps (stars) of axions including stability and strategies for detection. Then, I will discuss axion star formation in virialized dark mini-halos around PBHs through gravitational Bose-Einstein condensation.  I will analyze the conditions for mini-halos to kinetically produce axion stars before galaxy formation.  Under suitable conditions, we expect today up to ∼ 10^17 axion stars in a radius of 100 parsecs around the sun for the case of the QCD axion and a DM fraction of ~0.5% in axion stars. If a non-negligible number of axion stars survive tidal disruptions, then their presence today within the Milky Way halo would enhance DM indirect detection experiments.

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