Speaker: Ningqiang Song (Queen's U.)
Title: Microscopic black holes in neutrino telescopes, colliders and cosmology
Host: Da Liu
Zoom: https://zoom.us/j/186024391
Abstract:
If the length scale of possible extra dimensions is large enough, the fundamental Planck scale is lowered such that microscopic black holes could be produced in collisions of high-energy particles, which opens up a plethora of novel phenomena in terrestrial detectors and in the early Universe. Microscopic black holes from high-energy cosmic neutrino-nucleon collisions are characterized by unique topologies, distinct energy distributions and unusual ratios of hadronic-to-electronic energy deposition, visible through Cherenkov light echos due to delayed neutron recombination in IceCube-like detectors. In addition, these black holes evaporate through the emission of all particles that are kinematically and thermally allowed, including dark matter. This enables us to study the properties of dark sector from the missing momentum signatures at the next generation of colliders, regardless of the strength of the coupling between dark matter and the Standard Model. The microscopic black holes may account for part or all the dark matter relic density today and leave imprints on CMB, BBN and gamma ray background. Cosmological observations can serve as powerful tools to constrain the fundamental scale and the reheating temperature in the early universe.
User:
High-Energy Seminars
Time:
4:10pm - 5:10pm
Send Reminder:
Yes - 0 days 8 hour 0 minutes before start
Description:
Speaker: Ken Van Tilburg (NYU)
Title: Stellar Basins of Gravitationally Bound Particles
Host:
Zoom: https://zoom.us/j/186024391
Abstract:
I will describe and explore the consequences of a newly identified physical phenomenon: volumetric stellar emission into gravitationally bound orbits of weakly coupled particles such as axions, moduli, hidden photons, and neutrinos. While only a tiny fraction of the instantaneous luminosity of a star (the vast majority of the emission is into relativistic modes), the continual injection of these particles into a small part of phase space causes them to accumulate over astrophysically long time scales, forming what I call a "stellar basin", in analogy with the geologic kind. The energy density of the Solar basin can surpass that of the relativistic Solar flux at Earth's location after only a million years, for any sufficiently long-lived particle produced through an emission process whose matrix elements are unsuppressed at low momentum. This observation has immediate and striking consequences for direct detection experiments---including new limits on axion and hidden-photon parameter space independent of dark matter assumptions---and may also increase the prospects for indirect detection of weakly interacting particles around stars. [Based on https://arxiv.org/abs/2006.12431 and https://arxiv.org/abs/2008.08594.]
User:
High-Energy Seminars
Time:
4:10pm - 5:10pm
Description:
Speaker:
Title:
Host: Da Liu
Zoom: https://zoom.us/j/186024391