Precision determination of proton-to-electron mass ratio using antiprotonic helium atoms

2017 Fiscal Year Final Research Report

• Project/Area Number: 25247032
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: The University of Tokyo
• Principal Investigator: Hayano Ryugo 東京大学, 大学院理学系研究科(理学部), 名誉教授 (30126148)
• Project Period (FY): 2013-04-01 – 2018-03-31
• Keywords: 素粒子(実験) / 原子物理学実験 / 基礎物理定数 / CERN / 反陽子

Outline of Final Research Achievements

The purpose of this work is to determine the (anti)proton-to-electron mass ratio, one of the fundamental constants, to high precision by means of laser spectroscopy of antiprotonic helium atom (a metastable neutral atom consisting of an antiproton, an electron and a helium nucleus) . The work was done at the antiproton decelerator facility (AD) of CERN.
By comparing the transition frequencies of several accessible transitions to those obtained by the three-body quantum electrodynamics calculations, we determined the antiproton-to-electron mass ratio to a relative precision of 0.8 ppb (parts per billion), i.e., as precise as the proton-to-electron mass ratio recommended by the CODATA2010 fundamental constant adjustment. The result was published in 2016 in the Science magazine.

Free Research Field

素粒子、原子核、宇宙線および宇宙物理に関連する実験