PIRSA:22100142

Video URL

https://pirsa.org/22100142

Cosmological Signatures of Interacting Dark Sectors

Joseph, M. (2022). Cosmological Signatures of Interacting Dark Sectors. Perimeter Institute for Theoretical Physics. https://pirsa.org/22100142

Joseph, Melissa. Cosmological Signatures of Interacting Dark Sectors. Perimeter Institute for Theoretical Physics, Oct. 25, 2022, https://pirsa.org/22100142 

          @misc{ scivideos_PIRSA:22100142,
            doi = {10.48660/22100142},
            url = {https://pirsa.org/22100142},
            author = {Joseph, Melissa},
            keywords = {Particle Physics},
            language = {en},
            title = {Cosmological Signatures of Interacting Dark Sectors},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2022},
            month = {oct},
            note = {PIRSA:22100142 see, \url{https://scivideos.org/index.php/pirsa/22100142}}
          }

Melissa Joseph Boston University

Talk numberPIRSA:22100142
DOI10.48660/22100142
Source RepositoryPIRSA
Collection
Talk Type Scientific Series
Subject

Abstract

Models of dark sectors with a mass threshold can have important cosmological signatures. If, in the era prior to recombination, a relativistic species becomes non-relativistic and is then depopulated in equilibrium, there can be measurable impacts on the CMB as the entropy is transferred to lighter relativistic particles. In particular, if this "step'" occurs near z = 20,000, the model can naturally accommodate larger values of $H_0$. If this stepped radiation is additionally coupled to dark matter, there can be a meaningful impact on the matter power spectrum as dark matter can be coupled via a species that becomes non-relativistic and depleted. This can naturally lead to suppressed power at scales inside the sound horizon before the step, while leaving conventional CDM signatures for power outside the sound horizon. We study these effects and show such models can naturally provide lower values of $S_8$ than scenarios without a step. This suggests these models may provide an interesting framework to address the $S_8$ tension, both in concert with the $H_0$ tension and without.

Zoom Link:  https://pitp.zoom.us/j/96399847158?pwd=RkNHMkJHeEo5Q1Q2MkhHSHZ6c1BoQT09