|Title:||Macro Dark Matter|
|Speaker:||David Jacobs (UCT Cosmology)|
|Date:||Thursday, 25 February 2016|
|Time:||11:00 - 12:00|
Dark matter is a vital component of the current best model of our universe, ΛCDM. There are leading candidates for what the dark matter could be (e.g. weakly-interacting massive particles, or axions), but no compelling observational or experimental evidence exists to support these particular candidates, nor any beyond-the-Standard-Model physics that might produce such candidates. This suggests that other dark matter candidates, including ones that might arise in the Standard Model, should receive increased attention. I will discuss t he general class of dark matter candidates with characteristic masses and interaction cross-sections characterized in units of grams and cm^2, respectively — therefore these macroscopic objects are dubbed Macros. Such dark matter candidates could potentially be assembled out of Standard Model particles (quarks and leptons) in the early universe, or may be something else entirely new. A combination of Earth-based, astrophysical, and cosmological observations constrain a portion of the Macro parameter space. A few large regions of parameter space remains, however, most notably for nuclear-dense objects with masses in the range between that of a Snickers bar and a medium-sized asteroid.