Detailed report on the measurement of the positive muon anomalous magnetic moment to 0.20 ppm

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Muon g-2 Collaboration - (Author)
  • Chair of Phenomenology of Elementary Particles
  • University of Michigan, Ann Arbor
  • University of Liverpool (UOL)
  • Fermi National Accelerator Laboratory
  • RAS - Budker Institute of Nuclear Physics
  • City University of New York
  • University of Virginia
  • Novosibirsk State University
  • Lancaster University
  • Oak Ridge National Laboratory
  • University College London
  • Joint Institute for Nuclear Research
  • University of Illinois at Urbana-Champaign
  • Cornell University
  • National Institute for Nuclear Physics
  • Michigan State University
  • University of Washington
  • North Central College
  • The Cockcroft Institute
  • University of Massachusetts
  • University of Trieste
  • Boston University
  • University of Udine
  • University of Kentucky
  • Shanghai Jiao Tong University
  • Astrophysics and Cosmology (MOE)
  • Argonne National Laboratory
  • University of Pisa
  • RAS - P.N. Lebedev Physics Institute
  • Northern Illinois University
  • TUD Dresden University of Technology

Abstract

We present details on a new measurement of the muon magnetic anomaly, aμ=(gμ-2)/2. The result is based on positive muon data taken at Fermilab's Muon Campus during the 2019 and 2020 accelerator runs. The measurement uses 3.1 GeV/c polarized muons stored in a 7.1-m-radius storage ring with a 1.45 T uniform magnetic field. The value of aμ is determined from the measured difference between the muon spin precession frequency and its cyclotron frequency. This difference is normalized to the strength of the magnetic field, measured using nuclear magnetic resonance. The ratio is then corrected for small contributions from beam motion, beam dispersion, and transient magnetic fields. We measure aμ=116592057(25)×10-11 (0.21 ppm). This is the world's most precise measurement of this quantity and represents a factor of 2.2 improvement over our previous result based on the 2018 dataset. In combination, the two datasets yield aμ(FNAL)=116592055(24)×10-11 (0.20 ppm). Combining this with the measurements from Brookhaven National Laboratory for both positive and negative muons, the new world average is aμ(exp)=116592059(22)×10-11 (0.19 ppm).

Details

Original languageEnglish
Article number032009
JournalPhysical review d
Volume110
Issue number3
Publication statusPublished - 1 Aug 2024
Peer-reviewedYes

Keywords

ASJC Scopus subject areas