The New Muon G2 Experiment At Fermilab

A new measurement of the anomalous magnetic moment of the muon, $a_{\mu} \equiv (g-2)/2$, will be performed at the Fermi National Accelerator Laboratory with data taking beginning in 2017. The most recent measurement, performed at Brookhaven National Laboratory and completed in 2001, shows a 3.5 standard deviation discrepancy with the standard model prediction of $a_\mu$. The new measurement will accumulate 21 times those statistics using upgraded detection and storage ring systems, enabling a measurement of $a_\mu$ to 140 ppb, a factor of 4 improvement in the uncertainty the previous measurement. This improvement in precision, combined with recent and ongoing improvements in the evaluation of the QCD contributions to the $a_\mu$, could provide a 7.5$\sigma$ discrepancy from the standard model if the current difference between experiment and theory is confirmed, a possible indication of new physics.

There 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.

A new measurement of the anomalous magnetic moment of the muon, a? ≡ (g - 2)/2, will be performed at the Fermi National Accelerator Laboratory. The most recent measurement, performed at Brookhaven National Laboratory and completed in 2001, shows a 3.3-3.6 standard deviation discrepancy with the Standard Model predictions for a?. The new measurement will accumulate 21 times those statistics, measuring a? to 140 ppb and reducing the uncertainty by a factor of 4. The data acquisition system for this experiment must have the ability to record deadtime-free records from 700 ?s muon spills at a raw data rate of 18 GB per second. Data will be collected using 1296 channels of ?TCA-based 800 MSPS, 12 bit waveform digitizers and processed in a layered array of networked commodity processors with 24 GPUs working in parallel to perform a fast recording and processing of detector signals during the spill. The system will be controlled using the MIDAS data acquisition software package. Lastly, the described data acquisition system is currently being constructed, and will be fully operational before the start of the experiment in 2017.

Precision measurements of fundamental quantities have played a key role in pointing the way forward in developing our understanding of the universe. Though the enormously successful Standard Model (SM) describes the breadth of both historical and modern experimental particle physics data, it is necessarily incomplete. The muon $g-2$ experiment executed at Brookhaven concluded in 2001 and measured a discrepancy of more than three standard deviations compared to the Standard Model calculation. Arguably, this remains the strongest hint of physics beyond the SM. A new initiative at Fermilab is under construction to improve the experimental accuracy four-fold. The current status is presented here.

The measurement of the anomalous magnetic moment of muon provides a precision test of the Standard Model. The Brookhaven muon g-2 experiment (E821) measured the muon magnetic moment anomaly with 0.54 ppm precision, a more than 3 deviation from the Standard Model predictions, spurring speculation about the possibility of new physics. The new g-2 experiment at Fermilab (E989) will reduce the combined statistical and systematic error of the BNL experiment by a factor of 4. An overview of the new experiment is described in this article.

The New Muon (g-2) Collaboration at Fermilab has proposed to measure the anomalous magnetic moment of the muon, a{sub {mu}}, a factor of four better than was done in E821 at the Brookhaven AGS, which obtained a{sub {mu}} = [116592089(63)] x 10−11 ± 0.54 ppm. The last digit of a{sub {mu}} is changed from the published value owing to a new value of the ratio of the muon-to-proton magnetic moment that has become available. At present there appears to be a difference between the Standard-Model value and the measured value, at the ≈= 3 standard deviation level when electron-positron annihilation data are used to determine the lowest-order hadronic piece of the Standard Model contribution. The improved experiment, along with further advances in the determination of the hadronic contribution, should clarify this difference. Because of its ability to constrain the interpretation of discoveries made at the LHC, the improved measurement will be of significant value, whatever discoveries may come from the LHC.

This book reviews the present state of knowledge of the anomalous magnetic moment a=(g-2)/2 of the muon. The muon anomalous magnetic moment is one of the most precisely measured quantities in elementary particle physics and provides one of the most stringent tests of relativistic quantum field theory as a fundamental theoretical framework. It allows for an extremely precise check of the standard model of elementary particles and of its limitations.

The New Muon g-2 experiment (E989) at Fermilab will measure the muon anomalous magnetic moment, amu. E989 aims to measure amu to a precision of 0.14 parts-per-million, a factor of four improvement over the previous experimental measurement. The muon storage ring magnet was previously used in experiment E821 at Brookhaven National Laboratory. It was moved to Fermilab in order to attempt to improve the value of amu by utilizing Fermilab's higher energy proton source, the Main Injector. The storage region is filled with a highly precise magnetic field created by the superconducting coils surrounded by steel yokes. The muons are injected into the ring and kicked into a circular orbit and then decay into positrons and neutrinos. The positrons contain the same spin information as the parent muon and precess about the magnetic field. The tracking detector and calorimeter systems combine to measure the spin precession frequency oa and the magnetic field team will measure the average magnetic field felt by the muons. This paper will focus on the slow control system and environmental parameter monitoring of the MC-1 experimental hall, with initial focus on the temperature. This paper will also target the assembly and testing of the straw leak testing apparatus.

A new experiment at Fermilab will measure the anomalous magnetic moment of the muon with a precision of 140 parts per billion (ppb). This measurement is motivated by the results of the Brookhaven E821 experiment that were first released more than a decade ago, which reached a precision of 540 ppb. As the corresponding Standard Model predictions have been refined, the experimental and theoretical values have persistently differed by about 3 standard deviations. If the Brookhaven result is confirmed at Fermilab with this improved precision, it will constitute definitive evidence for physics beyond the Standard Model. The experiment observes the muon spin precession frequency in flight in a well-calibrated magnetic fi eld; the improvement in precision will require both 20 times as many recorded muon decay events as in E821 and a reduction by a factor of 3 in the systematic uncertainties. This paper describes the current experimental status as well as the plans for the upgraded magnet, detector and storage ring systems that are being prepared for the start of beam data collection in 2017.

We present a proposal to measure the anomalous magnetic moment of the muon to 0.14 ppm precision. This new g-2 experiment will be hosted by Fermilab making use of minor modifications to the existing accelerator complex. The experiment will recycle several components from the previous g-2 experiment E821 hosted at Brookhaven. In particular, the entire storage ring and magnet will be shipped to Fermilab. We cover the motivation for the experiment and review the measurement technique. We then focus on a new in-vacuo straw tracking system planned for the new experiment and its impact on searching for a permanent electric dipole moment of the muon.