3,247 research outputs found

    The measurement of muon g−2 at Fermilab

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    The Muon g −2 Experiment at Fermilab (E989) was built to repeat and improve the previous E821 Experiment at Brookhaven National Laboratory (BNL), aiming to reduce the experimental error by a factor of 4 to the final accuracy of 140 parts per billion (ppb). On April 7th, 2021, the E989 collaboration published the first result based on the first year of data taking (Run-1), measuring aμ = 0.001 165 920 40(54) with a precision of 460 ppb. The measured value is consistent with the BNL measurement and strengthens the long-standing tension with the data-driven SM prediction to a combined discrepancy of 4.2σ. On the theory side, however, new efforts involving lattice-QCD techniques are starting to question the current consensus on the theoretical prediction, demanding new improvements on both the experimental and theoretical sides. The Muon g−2 Experiment at Fermilab has now concluded its sixth and final year of data taking, and a new result based on the Run-2 and Run-3 data was published in August 2023. This paper briefly describes the Muon g − 2 Experiment at Fermilab and its current status

    The New Muon g−2 experiment at Fermilab

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    AbstractThere is a long standing discrepancy between the Standard Model prediction for the muon g−2 and the value measured by the Brookhaven E821 Experiment. At present the discrepancy stands at about three standard deviations, with a comparable accuracy between experiment and theory. Two new proposals – at Fermilab and J-PARC – plan to improve the experimental uncertainty by a factor of 4, and it is expected that there will be a significant reduction in the uncertainty of the Standard Model prediction. I will review the status of the planned experiment at Fermilab, E989, which will analyse 21 times more muons than the BNL experiment and discuss how the systematic uncertainty will be reduced by a factor of 3 such that a precision of 0.14 ppm can be achieved

    The Muon g−2g-2 experiment at Fermilab

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    The current ∼3.5σ\sim3.5\sigma discrepancy between the experimental measurement and theoretical prediction of the muon magnetic anomaly, aμa_{\mu}, stands as a potential indication of the existence of new physics. The Muon g−2g-2 experiment at Fermilab is set to measure aμa_{\mu} with a four-fold improvement in the uncertainty with respect to previous experiment, with an aim to determine whether the g−2g-2 discrepancy is well established. The experiment recently completed its first physics run and a summer programme of essential upgrades, before continuing on with its experimental programme. The Run-1 data alone are expected to yield a statistical uncertainty of 350 ppb and the publication of the first result is expected in late-2019.Comment: International Workshop on e+e- collisions from Phi to Psi (PhiPsi19), C19-02-25, FERMILAB-CONF-19-180-E-PP

    The Muon g-2 experiment at Fermilab

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    The upcoming Fermilab E989 experiment will measure the muon anomalous magnetic moment aμa_{\mu} . This measurement is motivated by the previous measurement performed in 2001 by the BNL E821 experiment that reported a 3-4 standard deviation discrepancy between the measured value and the Standard Model prediction. The new measurement at Fermilab aims to improve the precision by a factor of four reducing the total uncertainty from 540 parts per billion (BNL E821) to 140 parts per billion (Fermilab E989). This paper gives the status of the experiment.Comment: Proceedings for the XIIth Quark Confinement and the Hadron Spectrum conference (28 August 2016 to 4 September 2016

    Theoretical Status of Muon (g-2)

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    The theoretical status of the muon anomaly is reviewed including the recent change in the light by light hadronic correction. Specific attention is given to the implications of the shift in the difference between the BNL experimental result and the standard model prediction for sparticle mass limits. The implication of the BNL data for Yukawa unification is discussed and the role of gaugino mass nonuniversalities in the satisfaction of Yukawa unification is explored. An analysis of the BNL constraint for the satisfaction of the relic density constraint and for the search for dark matter is also given.Comment: 9 pages, Latex aipproc.Invited plenary talk at the Coral Gables Conference, at Fort Lauderdale, Florida, Dec 12-16, 2001. Vernon Hughes and Alan Krisch, session organizer
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