Events on Thursday, February 21st, 2019
- Cosmology Journal Club
- Time: 12:00 pm - 1:00 pm
- Place: 5242 Chamberlin Hall
- Abstract: Please visit the following link for more details:
http://cmb.physics.wisc.edu/journal/index.html
Feel free to bring your lunch!
If you have questions or comments about this journal club, would like to propose a topic or volunteer to introduce a paper, please email Ross Cawthon (cawthon@wisc.edu) and Santanu Das (sdas33@wisc.edu). - Theory Seminar (High Energy/Cosmology)
- Gravity safe, electroweak natural axionic solution to strong CP and SUSY mu problems
- Time: 2:30 pm
- Place: 5280 Chamberlin Hall
- Speaker: Howard Baer, University of Oklahoma
- Abstract: Particle physics models with Peccei-Quinn (PQ) symmetry breaking as a consequence of supersymmetry (SUSY) breaking are attractive in that
they solve the strong CP problem with a SUSY DFSZ-like axion,
link the SUSY breaking and PQ breaking intermediate mass scales
and can resolve the SUSY mu problem with a naturalness-required
weak scale mu term whilst soft SUSY breaking terms inhabit the
multi-TeV regime as required by LHC sparticle mass limits and
the Higgs mass measurement.
On the negative ledger, models based on global symmetries suffer a generic gravity spoliation problem. We present two models based on the discrete R-symmetry Z_{24}^R-- which may emerge from compactification of 10-d Lorentzian spacetime in string theory-- where the mu term and dangerous proton decay and R-parity violating operators are either suppressed or forbidden while a gravity-safe PQ symmetry emerges as an accidental approximate global symmetry leading to a solution to the strong CP problem and a weak-scale/natural value for the mu term. - Host: Vernon Barger
- Astronomy Colloquium
- Preparing for Earth 2.0: The Detailed Properties of Terrestrial Planets
- Time: 3:30 pm - 5:00 pm
- Place: 4421 Sterling Hall, Coffee and cookies 3:30 PM, Talk begins 3:45 PM
- Speaker: Andrew Vanderburg, University of Texas
- Abstract: Over the past thirty years, astronomers have made extraordinary progress in detecting planets around other stars. We now know that stars commonly host planets with a wider range of physical properties and system architectures than exist in our own solar system, and that planets likely outnumber stars in our galactic neighborhood. Now, planet detection technologies have advanced to the point where the direct detection of Earth-like exoplanets to search for biosignatures is within reach, and NASA is studying two space mission concepts with these goals in mind to potentially launch in the late 2030s. However, before this can happen, significant gaps in our knowledge of exoplanets must be covered so that these missions can be designed and their data can be interpreted. In my talk, I will describe work to fill in these gaps in our understanding of exoplanets. In particular, I will show how measurements of the bulk densities of small planets can constrain the planets' bulk composition and the presence of thick hydrogen/helium atmospheres. I will show how observations of white dwarf stars can reveal the elemental composition of rocky planets and the path towards using white dwarfs to learn about the compositional diversity of planets around other stars. Finally, I will show how modern artificial intelligence techniques can help measure precisely how common Earth analogs are, a crucial input parameter for designing missions to characterize Earth analogs.