Old Physics, New Tricks, and the Theory of Atomic Dark Matter
Francis-Yan Cyr-Racine
UBC
Cold dark matter (CDM) is a central pillar of the current cosmological
paradigm. While CDM predictions are in good agreement with observations of
the cosmic microwave background, large-scale structures, and the dynamics
of clusters and galaxies, the physics of dark matter is unknown. Recent
observations probing small astrophysical scales might indicate deviations
from the standard CDM scenario. We introduce a model of dark-matter physics
in which the dark sector, due to a new dark force, is made of atom-like
bound states. This model predicts different dark-matter properties on
small scales but retains the success of CDM on cosmological scales. In
the early Universe, the dark sector forms a tightly-coupled plasma
sustaining acoustic wave that can leave observable signatures in the
matter power spectrum. The kinetic decoupling of dark matter in this model
is significantly delayed compared to a typical WIMP model leading to a
significant damping of fluctuations on small scales. We revisit the atomic
physics necessary to capture the the thermal history of the dark sector
and show significant improvements over the standard hydrogen calculation
are required to make accurate predictions. We discuss constraints on
Atomic Dark Matter from galactic and cluster dynamics, cosmic microwave
background, the matter power spectrum, and big-bang nucleosynthesis.
Date: | Mercredi, le 11 janvier 2012 |
Heure: | 14:30 |
Lieu: | Université McGill |
| Ernest Rutherford Physics Building, R.E. Bell Conference Room (room 103) |
Contact: | Robert Rutledge |
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