Precision Magnetic Field Calibration for the Muon $g-2$ Experiment at Fermilab

Flay, D.

doi:10.22323/1.282.1075

Cited by 7 publications

(6 citation statements)

References 8 publications

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“…We expect that there might be a sign of the new physics beyond SM (BSM) in the muon g − 2 anomaly, which is 3-4 sigma deviation between the standard model (SM) prediction and the BNL experiment [1] suggested in 2004. To establish that, FermiLab and J-PARC (g − 2) µ experiment [2,3] aiming at a factor 4-5 improvement from the BNL experiment is forthcoming.…”

Section: Introductionmentioning

confidence: 99%

Analysis of systematic error in hadronic vacuum polarization contribution to muon g-2

Shintani¹,

Kuramashi²

2019

Proceedings of the 36th Annual International Symposium on Lattice Field Theory — PoS(LATTICE2018)

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We study systematic uncertainties in the lattice QCD computation of hadronic vacuum polarization (HVP) contribution to the muon g − 2. In this proceedings we investigate two systematic effects; finite volume (FV) effect, mass correction and cutoff effect. We evaluate FV effect at the physical pion mass on two different volumes of (5.4 fm) 4 and (10.8 fm) 4 using PACS10 configurations at the same cutoff scale, and for the mass correction, we compare two different pion mass points, m π = 135 MeV and 146 MeV pion, on large volume, L/a =10.8 fm and 8.1 fm respectively. Our results indicate that the chiral perturbation theory (ChPT) possibly underestimates FV effects in a long distance region, where multi-hadron state contributions including two-pion state become prominent. For the cutoff effect, we compare two forms of lattice vector operators, which are local and conserved (point-splitting) currents, by varying the cutoff scale on a more than (10 fm) 4 lattice at the physical point. The local-local current correlator shows smaller scaling violation than local-conserved one both in light and strange quark channels.

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Section: Introductionmentioning

confidence: 99%

Analysis of systematic error in hadronic vacuum polarization contribution to muon g-2

Shintani¹,

Kuramashi²

2019

Proceedings of the 36th Annual International Symposium on Lattice Field Theory — PoS(LATTICE2018)

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“…The mechanical systems of the trolley drive and garage are detailed in Sections 3.2.1 and 3.2.2 and the motion control system in Section 3.3. The motion control system also operates the in-vacuum, calibration NMR probe [12].…”

Section: Overview Of the Mechanical And Motion Control Systemmentioning

confidence: 99%

Design and performance of an in-vacuum, magnetic field mapping system for the Muon g-2 experiment

Corrodi,

De Lurgio,

Flay

et al. 2020

Preprint

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The E989 Muon g − 2 experiment at Fermilab aims to measure the anomalous magnetic moment, a µ , of the muon with a precision of 140 parts-per-billion. This requires a precise measurement of both the anomalous spin precession frequency, ω a , of stored muons and the average magnetic field in terms of the equivalent, free proton Larmor frequency, ω p . The measurement of ω p with a total systematic uncertainty of 70 parts-per-billion involves a combination of various nuclear magnetic resonance (NMR) probes. There are 378 probes mounted in fixed locations that constantly monitor field drifts. A water-based, cylindrical calibration probe provides the calibration in terms of the free proton Larmor frequency. A crucial element for the multi-step measurement of ω p is the regular mapping of the magnetic field over the muon storage region. The former E821 experiment at Brookhaven employed an in-vacuum field mapping system equipped with 17 NMR probes, which was developed by the University of Heidelberg. We have refurbished and upgraded this system with new probes and electronics. The upgrades include a new communication scheme incorporating time-division multiplexing to separate the important NMR reference clock from the data communication in order to reach the specifications for the accuracy and stability of the reference clock. The addition of 16-bit, 1 MSPS digitization of the NMR signals replaced the hardware-implemented zero-crossing counting of the E821 system. The digitized signals offer new capabilities in the NMR frequency analysis and its related systematic uncertainties. While the mechanical systems that move the field mapper inside the storage ring have been mostly refurbished from E821, the motion control system was completely replaced with a custom-built electronics centered around a commercial Galil motion controller. Both the field mapping NMR system and its motion control were successfully commissioned at Fermilab and have been in reliable operation during the first three data taking periods of the E989 experiment. This article will provide the details of the upgrades of the field mapper and its performance.

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“…Because the protons in the NMR probes are in molecules, their NMR frequency is proportional to but different from the free proton NMR frequency. To correct for these effects, we built a cylindrical probe [19] with pure water as the detection material. This probe has a well-known magnetic susceptibility chemical shift [20].…”

Section: The Absolute Calibration Probementioning

confidence: 99%

Magnetic Field Measurement and Analysis for the Muon g-2 Experiment

Hong¹

2019

Preprint

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The Muon g-2 Experiment (E989) at Fermilab measures the muon magnetic anomaly, aiming to resolve the greater than 3σ discrepancy between the previous measurement and the Standard Model calculation with an improved precision of 140 part-per-billion (ppb). In E989, the muon beam is stored in a ring magnet. The spin precession frequency ω a is measured by counting the decay positrons in 24 calorimeters, and the magnetic field is measured by nuclear magnet resonance (NMR) probes. An in-vacuum field scanning system consisting of NMR probes and read-out electronics has been implemented to measure the magnetic field applied to the muon beam. An additional 378 NMR probes, placed at fixed locations outside the vacuum chamber, monitor the field drift in between field scans. A high-accuracy probe was designed for calibrating the probes in the scanner. In this presentation, the magnetic field measurement hardware system and analysis methods will be described in detail. The progress of the Run-1 data analysis and improvements in Run-2 will be presented as well.

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Precision Magnetic Field Calibration for the Muon $g-2$ Experiment at Fermilab

Cited by 7 publications

References 8 publications

Analysis of systematic error in hadronic vacuum polarization contribution to muon g-2

Analysis of systematic error in hadronic vacuum polarization contribution to muon g-2

Design and performance of an in-vacuum, magnetic field mapping system for the Muon g-2 experiment

Magnetic Field Measurement and Analysis for the Muon g-2 Experiment

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