Direct neutrino mass measurement using Time of Flight

2014 Fiscal Year Final Research Report

• Project/Area Number: 24654077
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: High Energy Accelerator Research Organization
• Principal Investigator: MARUYAMA Takasumi 大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 准教授 (80375401)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: ニュートリノ / 質量 / 直接測定

Outline of Final Research Achievements

One of the most interesting topics in the elementary particle physics field is to measure the neutrino mass directly, not dm2 from neutrino oscillations. This research uses the energy dependence of the Time-of-Flight of neutrinos to measure it since the special relativity tells that lower energy neutrinos have longer Time-of-Flight. We first use the data taken for the T2K experiment, and had results, M_{nu}<2.4MeV. Then we investigate how to improve the results with the precise calibration of each hardware components of the T2K. We first measured the accuracy of the time syncronization of the new GPS system using TWSTFT (Two-Way Satellite Time and Frequency Transfer) with NICT laboratory, and the accuracy of the synchronization is better than 5ns. The calibration of the neutrino beam creation part was also performed, and the accuracy at present is better than 3ns.
Finally, the new experiment to have a good sensitivity was considered.

Free Research Field

素粒子実験