Conveners
DM IV
- Kaustubh Agashe (University of Maryland)
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Bibhushan Shakya (Deutsches Elektronen-Synchrotron (DE))25/05/2021, 16:30DM
This talk will discuss scenarios where dark matter abundance undergoes a "bounce" - a brief period of increase before thermal freezeout, following the standard exponential Boltzmann suppression - and its related phenomenological aspects.
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Jessica N. Howard (Department of Physics & Astronomy, UC Irvine), Jessica N. Howard (University of California Irvine (US))25/05/2021, 16:45DM
We consider how a modified cosmological history with a period of electroweak confinement could allow a WIMP dark matter candidate to escape current exclusion bounds. We consider an $SU(2)_L$ vector doublet fermionic dark matter candidate which confines with standard model fermions during this era. These composite particles interact, depleting the dark matter abundance. After these processes...
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Robert McGehee (University of Michigan)25/05/2021, 17:00DM
We present two distinct models which rely on 1st order phase transitions in a dark sector. The first is a minimal model for baryogenesis which employs a new dark SU(2) gauge group with two doublet Higgs bosons, two lepton doublets, and two singlets. The singlets act as a neutrino portal that transfers the generated baryon asymmetry to the Standard Model. The model predicts extra relativistic...
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Cara Giovanetti (NYU)25/05/2021, 17:15DM
We present novel constraints on sub-GeV dark matter models involving a light particle $\chi$ and a $U(1)'$ dark photon mediator. Using measurements of $N_{\textrm{eff}}$ from the CMB and post-BBN abundances of deuterium and helium-4, we derive constraints on the mass $m_{\chi}$ of the dark matter particle, assuming an MeV-scale mediator mass. Depending on the model parameters, we find that...
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Dr Fei Huang (ITP CAS and UC Irvine)25/05/2021, 17:30DM
Non-trivial dynamics within the dark sector can give rise to a complicated, non-thermal dark-matter phase-space distribution, which in turn can have a significant impact on the growth of the cosmic structure. In this talk, we explore the cosmological implications of such non-trivial dark-sector dynamics. We show how the non-trivial features in the phase-space distribution can lead to...
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Kevin Manogue (Lafayette College)25/05/2021, 17:45DM
The distribution of primordial dark-matter velocities can significantly influence the growth of cosmological structure. In principle, one can therefore exploit the halo-mass distribution in order to learn about the dark sector. In practice, however, this task is both theoretically and computationally intractable. In this talk, we present a simple one-line conjecture which can be used to...
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Siyang Ling (Rice University)25/05/2021, 18:00DM
We study the phenomenon of gravitational particle production as applied to a scalar spectator field in the context of α-attractor inflation. Assuming that the scalar has a minimal coupling to gravity, we calculate the abundance of gravitationally-produced particles as a function of the spectator's mass $m_χ$ and the inflaton's α parameter. If the spectator is stable and sufficiently weakly...
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Taoli Liu (the University of Alabama)25/05/2021, 18:15DM
I will discuss the Higgs-portal dark matter scenario in the 5-dimensional brane world cosmology, such as Randall-Sundrum cosmology and Gauss-Bonnet cosmology.
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