Archival data constrain properties of hypothetical dark-matter particles
DOI: 10.1063/PT.5.028369
Science : An experiment that ran at SLAC from 1980 to 1982 shot a beam of electrons at an aluminum target in hope of detecting evidence of axions, hypothetical particles devised to explain the absence of CP violation in the strong nuclear force. No axions were seen, and the negative result was duly written up. Decades later Rouven Essig of Stony Brook University in New York realized that the old experiment, known as E137, could also shed light on another hypothetical particle, the dark-matter candidate known as the χ. If χ particles behave as originally conceived, they would have caused a signal in E137 that the experimenters would have seen, but didn’t. Essig and his collaborators’ reinterpretation of the old experiment doesn’t rule out χ particles, but it does constrain their properties.
