arXiv subjects

B. Lee Roberts

Publications and source records attributed to B. Lee Roberts.

22 records · Page 2Linked to original sources

arXiv2002

Ultra High Precision with a Muon Storage Ring

The Muon $(g-2)$ experiment, E821, at the Brookhaven AGS has the goal to measure the muon anomalous magnetic moment to a relative accuracy of $\pm 3.5 \times 10^{-7}$. A superferric 14 m diameter storage ring has been constructed and an averaged magnetic field uniformity over the 90 mm diameter muon storage region of $\pm$ 1 part per million (ppm) has been achieved. A truncated double-cosine superconducting septum magnet (the inflector) was constructed along with a fast non-ferric kicker. The performance of the storage ring, along with the physics results are reviewed.

hep-ex↗

arXiv2001

Recent Progress on the BNL Muon g-2 Experiment

The status of the muon (g-2) experiment at the Brookhaven AGS is reviewed. An accuracy of 1.3 ppm on the mu^+ anomalous magnetic moment has been achieved and published. This result differs with the standard model prediction by about 2.5 standard deviations. A data sample with approximately seven times as much data is being analyzed, with a result expected in early 2001.

hep-ex↗

arXiv2001

Status of the Hadronic Contribution to the Muon (g-2) Value

With the recent interest in the measured and standard model values of the muon anomalous magnetic moment, a_mu, some confusion has arisen concerning our knowledge of the hadronic contribution to a_mu. In the dispersion integral approach to hadronic vacuum polarization effects, low energy contributions must be evaluated from data or in a model-dependent approach tested by data. At higher energies perturbative QCD has been used, sometimes in conjunction with data. The history of such evaluations is reviewed, and the prospects for further improvement are discussed. We conclude that not all published evaluations are on an equal footing or up-to-date. One must critically examine which, and how much information went into each analysis in order to determine which are more complete, and reliable.

hep-ph↗

arXiv2000

Status of the Muon (g-2) Experiment

The status of the muon (g-2) experiment, E821 at the Brookhaven AGS, is given. A new result with a precision of 5 parts per million has been obtained with direct muon injection into the ring and is presented. The theoretical motivation for the experiment, and a discussion of the sensitivity to non-standard model physics is also discussed.

hep-ex↗