Events at Physics
Events on Friday, April 12th, 2013
- Theory Seminar (High Energy/Cosmology)
- Radiatively-driven Natural Supersymmetry
- Time: 2:15 pm
- Place: 5280 Chamberlin Hall
- Speaker: Howard Baer, University of Oklahoma
- Abstract: While LHC has discovered a light Higgs boson at 125 GeV lying squarely within the predicted MSSM window, so far no sign of SUSY matter has emerged, thus requiring gluino and squark masses in the TeV-or-beyond regime. This seemingly exacerbates the Little Hierarchy Problem: why are m(Z) and m(h) ~100 GeV while sparticle masses are so heavy? We propose a conservative, model-independent measure of electroweak naturalness in supersymmetric models. Requiring finetuning at the ~10% level within the NUHM2 model, a SUSY spectrum with light higgsinos ~100-200 GeV but with TeV-scale highly mixed top squarks emerges which easily explains why m(h)~125 GeV while no sparticle signals appear at LHC8. A new SUSY signature--same-sign diboson production with minimal jet activity--emerges for LHC14. The smoking gun signature of light higgsinos are difficult to see at LHC but should be easily discovered at a linear e+e- collider, which in this case would be a higgsino, in addition to a Higgs factory. Thermally produced higgsino dark matter leaves room for axions as co-dark-matter particles. The light higgsinos should be visible at ton-scale noble liquid WIMP detectors.
- Physics Department Colloquium
- Superconductivity and the Pseudogap in theory and in copper-oxide based superconductors
- Time: 3:30 pm
- Place: 2241 Chamberlin Hall (coffee at 4:30 pm)
- Speaker: Andrew Millis, Columbia University
- Abstract: In the "high-Tc" copper oxide materials, superconductivity is believed not to arise from the electron-phonon coupling which causes superconductivity in conventional materials such as lead or mercury and is believed to be related in some way to the physics of the correlation driven ("Mott") metal insulator transition. In this talk I will summarize what is known about the underlying physics of the materials, explain why the theoretical problem is (NP) hard and present recent theoretical and computational progress which has led to new insights into electronically mediated superconductivity.
- Host: Chubukov