Programme

P.5 -- Poster, VCTP-46

Date: Tuesday, 5 October 2021

Time: 08:30 - 10:00

Characterizing the octant resolving of mixing angle $\theta_{23}$ in the neutrino oscillation and the impact to the CP violation measurement

Phan To Quyen (1,2), Cao Van Son (1,3), Nguyen Thi Hong Van (4), Ankur Nath (5), Tran Van Ngoc (1,2)

(1) Institute for Interdisciplinary Research in Science and Education (IFIRSE), Quy Nhon, Vietnam; (2) Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi, Viet Nam; (3) High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki, Japan ; (4) Institute of Physics, Vietnam Academy of Science and Technology, Hanoi, Vietnam; (5) Department of Physics, Tezpur University, Assam, India

Based on the highly sensitive techniques for neutrino observation developed by Super-K over the years, Hyper-Kamiokande (HyperK) represents a further improvement in sensitivity. HyperK, which is the third generation neutrino detector in Japan, was approved for construction in 2020 and plan to start data-taking in 2027 with the expected physics discoveries. HyperK will be a discovery machine for proton decays, detection of astronomical sources and CP violation search. In this topic, we continute exploring the physics potential of HyperK in measuring the $\theta_{23}$ mixing angle. We knew that the octant of $\theta_{23}$ can be improved significantly with constraints established by reactor & DUNE experiments and systematic improvement of appearance samples. This report will show the quantity characterizes the octant resolving ability from the contribution of $\nu_{\mu}$ and $\nu_{\tau}$ in the neutrino mass eigenstate $\nu_3$. It also shows the effects of the octant resolving to the measurement of CP violation in the lepton sector. If the octant of $\theta_{23}$ is known, CP violation sensitivity increases at true $\delta_{CP} = -\pi/2$. The sensitivity is improved significantly when the abibilty of octant resolving is optimal. And the relation of the octant resolving and CP violation sensitivity is expressed by the ratio of CP asymmetry and the statistic error of $\nu_{e}$ apprearance.

Presenter: Phan To Quyen