Sesh tells us how the void-galaxy cross correlation provides information about cosmology via redshift space distortions and (importantly) the Alcock Paczynski effect. The information is independent of Baryon Acoustic Oscillations (BAO) and improves error bars by up to a factor of four. The combination of voids and BAO have very interesting insights into the Hubble discrepancy and the late-time acceleration of the Universe.

Speaker: Seshadri Nadathur

(the most relevant) Papers: https://arxiv.org/abs/2001.11044​ and https://arxiv.org/abs/1904.01030

Reference for cosmological perturbation theory: https://arxiv.org/abs/0809.4944​

Reference for Post Newtonian Theory

Paper: https://arxiv.org/abs/2001.00394

Graham tells us how Big Bang Nucleosynthesis (BBN) and the Cosmic Microwave Background can be used to constrain the potential existence of particles beyond the Standard Model.

The focus is on light dark matter (masses less than 1GeV), which escapes direct detection bounds by being too light to kick nucleons hard enough and is most interesting to cosmology because it has precisely the masses relevant in the early universe processes we can “observe”, e.g. BBN.

Graham volunteered to give this talk on less than 36 hours notice, so huge thanks to him for pulling something together so quickly!!

Speaker: Graham White https://www.triumf.ca/theory/graham-white

Graham’s paper: https://arxiv.org/abs/2003.02273