4 research outputs found
Reduction of coherent betatron oscillations in a muon g-2 storage ring experiment using RF fields
This work demonstrates that two systematic errors, coherent betatron
oscillations (CBO) and muon losses can be reduced through application of radio
frequency (RF) electric fields, which ultimately increases the sensitivity of
the muon experiments. As the ensemble of polarized muons goes around a
weak focusing storage ring, their spin precesses, and when they decay through
the weak interaction, , the decay
positrons are detected by electromagnetic calorimeters. In addition to the
expected exponential decay in the positron time spectrum, the weak decay
asymmetry causes a modulation in the number of positrons in a selected energy
range at the difference frequency between the spin and cyclotron frequencies,
. This frequency is directly proportional to the magnetic
anomaly , where is the g-factor of the muon, which is
slightly greater than 2. The detector acceptance depends on the radial position
of the muon decay, so the CBO of the muon bunch following injection into the
storage ring modulate the measured muon signal with the frequency
. In addition, the muon populations at the edge of the beam
hit the walls of the vacuum chamber before decaying, which also affects the
signal. Thus, reduction of CBO and unwanted muon loss increases the
measurement sensitivity. Numerical and experimental studies with RF electric
fields yield more than a magnitude reduction of the CBO, with muon losses
comparable to the conventional method.Comment: 14 pages, 25 figure
Mu2e Run I Sensitivity Projections for the Neutrinoless mu(-) -> e(-) Conversion Search in Aluminum
The Mu2e experiment at Fermilab will search for the neutrinoless μ−→e− conversion in the field of an aluminum nucleus. The Mu2e data-taking plan assumes two running periods, Run I and Run II, separated by an approximately two-year-long shutdown. This paper presents an estimate of the expected Mu2e Run I search sensitivity and includes a detailed discussion of the background sources, uncertainties of their prediction, analysis procedures, and the optimization of the experimental sensitivity. The expected Run I 5σ discovery sensitivity is Rμe=1.2×10−15, with a total expected background of 0.11±0.03 events. In the absence of a signal, the expected upper limit is Rμe<6.2×10−16 at 90% CL. This represents a three order of magnitude improvement over the current experimental limit of Rμe<7×10−13 at 90% CL set by the SINDRUM II experiment.</jats:p