Colloquium within National Seminar Theoretical High Energy Physics (DRSTP):
Friday 18 March, 11.15h, at Nikhef/CWI in Z011.
Speaker: Subdoh Patil (LEI)
Title: “Spectral Distortions of the Cosmic Microwave Background (for Particle Physicists)”
One of the most striking confirmations of big bang cosmology was the detection of relic radiation with an almost perfect black body spectrum. Almost. Within the standard cosmological model, one expects to find small departures from a black body spectrum — spectral distortions — that directly probe any energy release phenomenon in the early universe before recombination which didn’t have time to sufficiently thermalize. As such, spectral distortions not only offer a probe of the thermal history of the Universe, but also a number of scenarios of interest to particle physicists. These include the decay of long lived particles, (dark sector) phase transitions, topological defects, the presence of axions, and a range of other exotic beyond the Standard Model scenarios. Furthermore, spectral distortions offer a means to constrain stochastic backgrounds of gravitational waves at scales inaccessible to other probes. In this talk, I will review the basic physics of spectral distortions of the cosmic microwave background, what one can hope to learn from it if you’re a particle physicist, and offer an overview of current proposals to measure them with the next generation of space based observations.
This colloquium will be hybrid: