Measurement of the Kinetic Energy Distribution of Pionic Hydrogen Atoms in Liquid Hydrogen

Abstract

In this experiment¹’² time-of-flight distributions of neutrons produced by the charge exchange reaction

$${\pi ^ - }p \to {\pi ^0}n $$

((1))

π⁻ p → π⁰ n (1) of π⁻ p atoms in liquid hydrogen were measured. The data were used to determine the pion mass difference m_π — m _π o and, as a side result, the kinetic energy distribution of the pionic hydrogen atoms just before the charge exchange reaction.