from the mysterious-muon-magnetic-moment dept.
The Muon g-2 experiment (pronounced "gee minus two") is designed to look for tantalizing hints of physics beyond the Standard Model of particle physics. It does this by measuring the magnetic field (aka the magnetic moment) generated by a subatomic particle known as the muon. Back in 2001, an earlier run of the experiment at Brookhaven National Laboratory found a slight discrepancy, hinting at possible new physics, but that controversial result fell short of the critical threshold required to claim discovery.
Now, Fermilab physicists have completed their initial analysis of data from the updated Muon g-2 experiment, showing "excellent agreement" with the discrepancy Brookhaven recorded. The results were announced today in a new paper published in the journal Physical Review Letters.
1.) B. Abi, et al. Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm [open], Physical Review Letters (DOI: 10.1103/PhysRevLett.126.141801)
2.) T. Albahri et al. (The Muon g−2 Collaboration) Magnetic-field measurement and analysis for the Muon g−2 Experiment at Fermilab [open], Physical Review A (DOI: 10.1103/PhysRevA.103.042208)
3.) T. Albahri et al. (Muon g−2 Collaboration)Measurement of the anomalous precession frequency of the muon in the Fermilab Muon g−2 Experiment [open], Physical Review D (DOI: 10.1103/PhysRevD.103.072002)
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What do touch screens, radiation therapy and shrink wrap have in common? They were all made possible by particle physics research. Discoveries of how the universe works at the smallest scale often lead to huge advances in technology we use every day.
Scientists from the U.S. Department of Energy’s (DOE) Argonne National Laboratory and Fermi National Accelerator Laboratory, along with collaborators from 46 other institutions and seven countries, are conducting an experiment to put our current understanding of the universe to the test. The first result points to the existence of undiscovered particles or forces. This new physics could help explain long-standing scientific mysteries, and the new insight adds to a storehouse of information that scientists can tap into when modeling our universe and developing new technologies.
The experiment, Muon g-2 (pronounced Muon g minus 2), follows one that began in the ‘90s at DOE’s Brookhaven National Laboratory, in which scientists measured a magnetic property of a fundamental particle called the muon.
The Brookhaven experiment yielded a result that differed from the value predicted by the Standard Model, scientists’ best description of the makeup and behavior of the universe yet. The new experiment is a recreation of Brookhaven’s, built to challenge or affirm the discrepancy with higher precision.
The Standard Model very precisely predicts the muon’s g-factor — a value that tells scientists how this particle behaves in a magnetic field. This g-factor is known to be close to the value two, and the experiments measure their deviation from two, hence the name Muon g-2.
[Update: This story appears to be a dupe of Latest Muon Measurements Hint at Cracks in the Standard Model; as there are already comments here, it will remain posted for discussion. --martyb]