Events at Physics |
Events During the Week of December 7th through December 14th, 2008
Monday, December 8th, 2008
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Transport Studies in HSX
- Time: 12:05 pm
- Place: 1227 Engineering Hall
- Speaker: Jeremy Lore, UW-Madison, Dept. of ECE
- Plasma Theory Seminar
- Initiation of Ballooning Instability by Reconnection in Near-Earth Plasma Sheet
- Time: 4:00 pm
- Place: 514 ERB
- Speaker: Dr. Ping Zhu, UW-Madison, CPTC & Dept of EP
Tuesday, December 9th, 2008
- Chaos & Complex Systems Seminar
- A technique for modeling radar interferograms without phase unwrapping: Application to the M 5 Fawnskin, California earthquake of 4 December 1992
- Time: 12:05 pm
- Place: 4274 Chamberlin (Refreshments will be served)
- Speaker: Kurt Feigl, UW Department of Geology and Geophysics
- Abstract: Interferometric analysis of synthetic aperture radar images (InSAR) measures the phase shifts between two images acquired at two distinct times. These ambiguous "wrapped" phase values range from 1/2 to +1/2 cycles. The standard approach interprets the phase values in terms of the change in distance between the ground and the radar instrument by resolving the integer ambiguities in a process known as "unwrapping". To avoid unwrapping, we have developed, validated, and applied a new method for modeling the wrapped phase data directly. The method defines a cost function in terms of wrapped phase to measure the misfit between the observed and modeled values of phase. By minimizing the cost function with a simulated annealing algorithm, the method estimates parameters in a nonlinear model. Since the wrapped phase residuals are compatible with a von Mises distribution, several parametric statistical tests can be used to evaluate the fit of the model to the data. The method, named General Inversion for Phase Technique (GIPhT), can handle noisy, wrapped phase data. Applying GIPhT to two interferograms in the area of Fawnskin, California, we estimate a set of model parameters describing a magnitude 5 aftershock of the 1992 Landers earthquake. The resulting simulation fits the data well. The phase final residuals have a circular mean deviation less than 0.15 cycles/datum. Sampling the final residuals, we find the circular standard deviation of a phase measurement to be approximately 0.2 cycle, corresponding to 6 mm in range.
Wednesday, December 10th, 2008
- Phenomenology Seminar
- Supersymmetric Electroweak Symmetry Breaking
- Time: 2:30 pm
- Place: 5280 Chamberlin Hall
- Speaker: Puneet Batra, Columbia University
- Host: V. Barger
Thursday, December 11th, 2008
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Pseudo-Goldstone Baryogenesis
- Time: 4:30 pm
- Place: 4274 Chamberlin
- Speaker: Mike Trott, Perimeter Institute
- Abstract: We examine the nature of electroweak Baryogenesis when the Higgs boson's properties are modified by the effects of new physics. We utilize the effective potential to one loop while retaining parametrically enhanced dimension six operators of O(v^2/f^2) in the Higgs sector. These parametrically enhanced operators would be present if the Higgs is a pseudo-goldstone boson of a new physics sector with a characteristic mass scale Lambda ~ a few TeV, a coupling constant (4 pi) > g > 1 and a strong decay constant scale f = Lambda/g. We find that generically the effect of new physics of this form allows a sufficiently first order electro-weak phase transition so that the produced Baryon number can avoid washing out, and has enhanced effects due to new sources CP violation. The conditions we find for pseudo-goldstone baryogenesis to occur are examined in the context of Little Higgs models, and are found to give surprising insights into the nature of some of the viable parameter space for Little Higgs models.
- Host: S Mantry
Friday, December 12th, 2008
- Last Day of Class
- Phenomenology Seminar
- Gauge Boson Scattering at the LHC
- Time: 2:30 pm
- Place: 5280 Chamberlin Hall
- Speaker: Barbara Jager, University of Wurzburg
- Physics Department Colloquium
- Holiday Colloquium
- Time: 4:00 pm
- Place: 2103 Chamberlin Hall
- Speaker: Holiday Colloquium
- Host: Grad Students