Events at Physics
Events on Friday, May 11th, 2012
- Last Day of Class - No Colloquium
- Dissertation Defense
- Observation of Electron Antineutrino Disappearance at the Daya Bay Experiment
- Time: 8:30 am
- Place: 4274 Chamberlin Hall
- Speaker: Bryce Littlejohn, UW Department of Physics Graduate Student
- Abstract: Many experiments in the last few decades have demonstrated the neutrino's ability to change flavor while traveling through space and time, or oscillate. One of the last remaining unknown parameters describing this oscillation, theta13, is crucial in defining the magnitude of CP-violation in the lepton sector and examining the neutrino's role in the universe's matter-antimatter asymmetry. The Daya Bay experiment has measured theta13 with unprecedented precision by observing disappearance of reactor antineutrinos with identical detectors at multiple reactor distances. With roughly two months of data, the experiment has measured the value of sin^2(2theta13) to be 0.092 +- 0.017, and excluded the theta13=0 hypothesis to five standard deviations. This talk will describe the Daya Bay experiment, present an independent analysis of first Daya Bay data, and discuss the implications of this exciting measurement.
- Host: Heeger
- Theory Seminar (High Energy/Cosmology)
- Structure of dimension-six derivative interactions in pseudo Nambu-Goldstone N Higgs doublet models
- Time: 1:00 pm
- Place: 5280 Chamberlin Hall
- Speaker: Yasuhiro Yamamoto, University of Tokyo
- Abstract: We derive the general structure of dimension-six derivative interactions in the N Higgs doublet models, where Higgs fields arise as pseudo Nambu-Goldstone modes of a strongly interacting sector. We show that there are several relations among the dimension-six operators, and therefore the number of independent operators decreases compared with models on which only SU(2)_L x U(1)_Y invariance is imposed. As an explicit example, we derive scattering amplitudes of longitudinal gauge bosons and Higgs bosons at high energy on models involving two Higgs doublets, and compare them with the amplitudes in the case of one Higgs doublet.