Events at Physics |
Events on Tuesday, October 14th, 2014
- Chaos & Complex Systems Seminar
- Human Longevity: Where are we going and how are we getting there?
- Time: 12:05 pm - 1:00 pm
- Place: 4274 Chamberlin Hall (Refreshments will be served)
- Speaker: Alberto Palloni, UW Department of Sociology
- Abstract: Our species has been around for 250,000 years or so. During nearly 249,800 of these, life expectancy at birth was steady at a level hovering around 25 years. But over the last 200 years, that is 0.1 percent of our species' lifetime on the planet, life expectancy at birth increased from about 25 years to about 80 years or, equivalently, Homo added 2.6 months of life per year. Some countries have cruised along with a pace of gains in survival twice as large as this average. It turns out that, on average and contrary to most past forecasts, life expectancy at birth has been going up linearly for a long time.
How did this happen? Can we keep it going? Aside from occasional setbacks (HIV, collapse of social organizations, wars, Ebola(?)) can one harbor the hope that by the year 2050 newborn cohorts will be expected to live 90-100 years? And if so, how healthy could the 90% of newborns who will make it to their 90th birthday expected to be? And what does this do to the course of human evolution?
- Host: Clint Sprott
- Theory Seminar (High Energy/Cosmology)
- Detecting Boosted Dark Matter from the Sun with Large Volume Neutrino Detectors
- Time: 3:00 pm - 4:00 pm
- Place: 5280 Chamberlin Hall
- Speaker: Josh Berger
- Abstract: We study novel thermal Dark Matter (DM) scenarios where the annihilation of DM captured in the Sun produces boosted stable particles in the dark sector. These stable particles can be the annihilating DM itself, as in the scenario of semi-annihilating DM where DM possesses non-minimal stabilization symmetries, or can be a lighter subdominant DM component, as in the scenario of a multi-component DM sector. We investigate both of these possibilities and present concrete models as proofs of concept, considering DM mass in the wide range of O(1)-O(100) GeV. With a large Lorentz boost, these boosted DM can be detected in large volume terrestrial experiments, such as experiments designed for neutrino physics or proton decay searches, via neutral-current-like interactions with nuclei or electrons. In particular, we propose a search for proton tracks pointing towards the Sun, which is a primary detection channel for boosted DM from the Sun at neutrino experiments. We focus on studying the signals at Cherenkov-radiation-based detectors such as Super-Kamiokande (SK) and its upgrade Hyper-Kamiokande (HK). We find that with spin-dependent scattering as the dominant DM-nucleus interaction at low energies, boosted DM can leave detectable signals at SK or HK, while being consistent with current DM direct detection constraints. The boosted DM signal highlights the distinctive signatures that can arise in non-minimal DM sectors.
- Host: Ran Lu