Jigsaw Puzzle : Pion-muon-electron (pi-mu-e) decay chain

EDITORS COMMENTS

This print showcases the iconic pion-muon-electron (pi-mu-e) decay chain, captured through an emulsion photograph. Taken in 1948 by Cecil Powell, a pioneering English physicist in particle physics, this image offers a glimpse into the intricate world of subatomic particles. In the top left corner of the picture, we witness the entry point of a charged cosmic ray pion. As it swiftly decays, two distinct tracks emerge - one belonging to a muon and another representing a neutrino. The muon's path can be traced downwards towards the bottom of the image while gradually becoming denser as it slows down before its own decay. At the bottom right section of this remarkable snapshot lies evidence of yet another transformation within this decay chain. Here we observe a faint track heading to the right, indicating that the muon has now transformed into an electron. Accompanying this process is yet another neutrino departing silently without leaving any visible trace. The significance of this photograph lies not only in its aesthetic appeal but also in its scientific value. It symbolizes Powell's groundbreaking work utilizing photographic emulsions to record particle tracks and contributes to our understanding of fundamental particles and their behavior within nuclear emulsions. As we delve deeper into particle physics odyssey, images like these serve as reminders that there is still much more to uncover about our universe at both macroscopic and microscopic scales.