Internet-based experiment to measure the muon lifetime in real time

We describe a web-based experiment to measure the lifetime of cosmic-ray muons that stop in a liquid scintillator detector. Our experimental setup consists of a container filled with liquid scintillator, a photomultiplier tube, a commercial electronics board (STEMlab 125-14) that includes an ARM-based computer with a field programmable gate array (FPGA) and an analog-to-digital converter (ADC). The muons we detect arrive at the detector as part of the secondary cosmic rays that are produced high in the Earth atmosphere when energetic primary cosmic rays collide with nitrogen and oxygen nuclei. The software we use to run this experiment in real time on the web uses Python code on the computer of the Red Pitaya board and HTML/Javascript code on the webpage. The experiment is located at the Centro Interdisciplinario de Investigación y Enseñanza de la Ciencia on the campus of the Benemérita Universidad Autónoma de Puebla (BUAP) in the city of Puebla, ´ Mexico. We report a value for the effective mean lifetime of the stopping muons of 2.051 ± 0.009 µs. This result is lower than the 2.197 µs mean muon lifetime in vacuum due to the capture of negative muons by the nuclei of the atoms of the detector material. The experiment can be accessed through the webpage https://ciiec.buap.mx/Muon-Decay.