The search for neutrinoless double beta decay of EXO-200 and nEXO with barium tagging

by Yang Lan (T)

Tuesday 29 Sep 2020, 10:00 → 11:00 Asia/Shanghai

A419 (IHEP)

Abstract: The properties of neutrino remains to be one of the biggest mysteries in particle physics. Neutrinoless double beta decay (0νββ) is the most sensitive approach to validate whether neutrinos are their own antiparticles and to reveal their absolute mass scale. If detected, 0νββ will also be the first lepton-number violating process and help to explain the matter-antimatter asymmetry in our universe. The EXO (Enriched Xenon Observatory) is searching for 0νββ in xenon-136. Our recently completed experiment EXO-200 found xenon-136 has half-life 𝘛₁⸝₂>3.5×10²⁵ years. The upgraded experiment nEXO will have 0νββ 𝘛₁⸝₂ sensitivity above 10²⁸ years. The sensitivity of nEXO is limited by its background level. Barium tagging is the ultimate method for reducing the background. An ion trap is being developed for the barium tagging purpose of nEXO to reach its ultimate sensitivity on 0νββ. Prototypes of the ion trap has been built and tested, the experiment results demonstrated successful ion trapping, cooling and mass filtering for barium tagging. About the speaker: Yang Lan is finishing his PhD at the University of British Columbia (expected to graduate on November 2020). He is currently a member of the TITAN collaboration at TRIUMF, Canada's national laboratory of nuclear and particle physics; he is also a member of the EXO-200 and the nEXO collaborations. From 2011 to 2012, he was a member of the optical frequency standard group at the Center for Gravitational Experiment of the Huazhong University of Science and Technology as an undergrad; he simulated and designed the first generation ion trap for the optical clock. From 2013 to 2014, he studied acoustics and musical acoustics during MSc at the Department of physics and astronomy at UBC; he measured and modeled the Chinese instruments guqin and the xiao; he further optimized, designed and made xiaos of excellent acoustical performance. Since 2015, he participated the high precision mass measurement experiments of short-lived isotopes in the TITAN collaboration; he participated the underground experiment of EXO-200 and was the data quality analyzer during its last two-year's data taking; he designed, simulated and built the ion trap for the barium tagging of nEXO. -------- Zoom Meeting ID: 667 2580 3830 or by clicking: https://weidijia.zoom.com.cn/j/66725803830