Weak Interaction Discussion Group Seminar: Zepeng Li, Duke University, “Atmospheric Tau Neutrinos in Super-Kamiokande”

Event time: 
Tuesday, April 11, 2017 - 12:00pm to 1:00pm
Wright Lab, EAL 108 Conference Room (EAL108) See map
268 Whitney Avenue
New Haven 06520
(Location is wheelchair accessible)
Event description: 

Super-Kamiokande is a 50 kiloton water Cherenkov detector with 22.5 kiloton of fiducial volume located at a depth of 1,000 meters in Japan. The experiment has accumulated atmospheric neutrino data since 1996. I will talk about a search for atmospheric tau neutrino appearance and a measurement of charged-current tau neutrino cross section using the atmospheric neutrino data in Super-Kamiokande. A neural network algorithm is applied to identify charged-current tau neutrino interactions in the detector. Using 5,326 days of atmospheric neutrino data, Super- Kamiokande measures a normalization of the tau events to be 1.47±0.32 under the assumption of the normal mass hierarchy, relative to the expectation of unity. The result excludes the hypothesis of no-tau-appearance with a significance of 4.6σ. The observed charged-current tau neutrino interactions are used to measure a flux-averaged charged-current tau neutrino cross section to be (0.94 ± 0.20) × 10^{−38} cm^2 , to be compared with the theoretical flux-averaged charged-current tau neutrino cross section of 0.64 × 10^{−38} cm^2.

A pizza lunch will be served starting at 11:45 outside the WL/EAL-108 Conference Room.