2017 Fall Graduate Colloquium Series: Chao Zhang/Bryan Caraway

DateSeptember 29, 2017
Time3:35 - 5:00 pm
LocationBaylor Sciences Building, Room A202
Description
Chao Zhang


The Gravitational Lensing Effect of Gravastars


General relativity has told us that the light could be bended by matter. In this way the actual
position of the light source may be different from the observation. This kind of phenomenon is
very similar to the effect of a lens so we just call it the gravitational lensing effect. I will give a brief review of the concept of the gravitational lensing effect to illustrate the basic ideas. Besides, I will also show some consequence from the analysis of the gravitational lensing by gravastars to make this physical procedure more vivid and explicit.


Reference: T. Kubo and N. Sakai, Phys. Rev. D 93, 084051 (2016)



Bryan Caraway


New Measurement of Antineutrino Oscillation with the Full Detector Configuration at Daya Bay


The completion of the full construction of the Daya Bay Reactor Neutrino Experiment has
resulted in a new measurement for electron antineutrino disappearance. Including the 404
days of data collected from October 2012 to November 2013 resulted in a total exposure of
6.9×105 GWth ton days, a 3.6 times increase over previous results. Moreover, improvements
have limited variation to .2% between detectors, and reduced background by a factor of 2 in
the farthest detectors. Direct prediction of the antineutrino signal in the far detectors based
on the measurements in the near detectors explicitly minimized the dependence of the
measurement on models of reactor antineutrino emission. As a result, the uncertainties in
the estimates were halved. An analysis of the relative antineutrino rates and energy spectra
between detectors gave uncertainties of sin22θ13 = 0.084±0.005 and |Δm2 ee| = (2.42±0.11)×10−3 eV2 in the three-neutrino framework.


Reference: F.P. An et al. (Daya Bay Collaboration), Phys. Rev. Lett. 115, 111802 (2015)

For more information contact: Dr. Ken Hatakeyama 254-710-2511
PublisherDepartment of Physics
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