3:30–5:00 pm ERC 161
Title: The Dark Side of the Universe
Abstract: The nature of the dark matter in the Universe is among the longest and most important outstanding problems in all of modern physics. The ordinary atoms of our daily experience constitute only 5% of all matter and energy in the cosmos. The remaining 95% is made up of 25% dark matter and 70% dark energy, whose nature remains a mystery. I’ll begin by discussing the evidence that dark matter is the bulk of the mass in the Universe, and then turn to the hunt to understand its nature. Leading candidates are fundamental particles including Weakly Interacting Massive Particles (WIMPs), axions, sterile neutrinos, light dark matter, as well as primordial black holes. I will discuss multiple experimental searches: at CERN in Geneva; in underground laboratories; with space telescopes; with gravitational wave detectors; and novel experimental efforts using paleodetectors -- ancient minerals from deep underground. I’ll tell you about our idea of Dark Stars, early stars made primarily of hydrogen and helium from the Big Bang but powered by dark matter heating, and the possibility that the James Webb Space Telescope has already discovered them. JWST has made surprising discoveries: too many and too massive early galaxies (potentially in conflict with standard LCDM cosmology); unexplained supermassive black holes; and little red dots. Supermassive Dark Stars and their remnants offer solutions to all of these cosmic dawn puzzles. At the end of the talk, I'll turn to dark energy and argue against controversial evidence for its time variation.
Zoom: https://uchicago.zoom.us/j/93608741174?pwd=W4lXrXadGKmxeISt9r0H1k5jLxhRNp.1
