|2018 Fall Graduate Colloquium Series|
Search for Proton Decay via p → e+ π0 and p→ μ+ π0 at Super-Kamiokande
The Standard Model describes many interactions between the electroweak and strong force, but it still lacks explanations for many phenomena, such as the imbalance between anti-matter and matter, or the existence of neutrino masses. One of the models beyond the Standard Model that explains these phenomena is the Grand Unified Theory (GUT). One of the phenomena the GUT predicts is proton decay. Observing the decay of a proton is a step towards proving that our world is described by the GUT. Super-Kamiokande is one of the experiments looking for the evidences of proton decay via the p → e+ π0 and p → μ+ channel. Data from 1995-2015 were analyzed. No candidates of proton decay were observed. The lower limit on the proton lifetime were set to 1.6 X 1034 years for the e+ channel and 7.7 X 1033 years for the μ+ channel at 90% confidence level.
 K. Abe et al. (Super-Kamiokande Collaboration. Phys. Rev. D 95, 012004 (2017)
Measurement of the Casimir Force between Two Spheres
The Casimir force arises from imposing boundary conditions on the quantum electromagnetic vacuum energy. This force is a macroscopic manifestation of the vacuum; however, the force is very small and difficult to detect. Measurements have been restricted to parallel plate and sphere-plate configurations due to the difficulties in alignment for more complex geometries. Here, the measurement of the Casimir force between two gold spheres is carried out using an atomic force microscope. Scanning in the x-y plane and maintaining 30-400 nm separation provides consistent results with Lifshitz’s theory using proximity force approximation.
Garrett, J. L., Somers, D. A. T., & Munday, J. N. (2018). Measurement of the Casimir Force between Two Spheres. Physical Review Letters, 120(4). https://doi.org/10.1103/physrevlett.120.040401
For more information contact: Dr. Howard Lee 254-710-2277