118362394
Calculation of the parity-violating 5s-6s E1 amplitude in the rubidium atom
Currently, the theoretical uncertainty limits the interpretation of the atomic parity-nonconservation (PNC) measurements. We calculate the PNC 5s-6s electric dipole transition amplitude in rubidium and demonstrate that rubidium is a good candidate to search for new physics beyond the standard model since accuracy of the atomic calculations in rubidium can be higher than in cesium. PNC in cesium is currently the best low-energy test of the standard model; therefore, similar measurements for rubidium present a good option for further progress in the field. We also calculate the nuclear spin-dependent part of the PNC amplitude, which is needed for the extraction of the nuclear anapole moment from the PNC measurements. DOI:10.1103/PhysRevA.86.062512
52994365
Strongly enhanced atomic parity violation due to close levels of opposite parity
We present calculations of nuclear-spin-dependent and nuclear-spin-independent parity-violating amplitudes in Ba, Ra,Ac+, Th, and Pa. Parity nonconservation in these systems is greatly enhanced due to the presence of very close electronic energy levels of opposite parity, large nuclear charge, and strong nuclear enhancement of parity-violating effects. The presented amplitudes constitute several of the largest atomic parity-violating signals predicted so far. Experiments using these systems may be performed to determine values for the nuclear anapole moment, a P-odd T -even nuclear moment given rise to by parity-violating nuclear forces. Such measurements may prove to be valuable tools in the study of parity violation in the hadron sector. The considered spin-independent transitions could also be used to measure the ratio of weak charges for different isotopes of the same atom, the results of which would serve as a test of the standard model and also of neutron distributions. Barium, with seven stable isotopes, is particularly promising in this regard.
27741778
Revisiting parity nonconservation in cesium.
We apply the sum-over-states approach to calculate partial contributions to parity nonconservation (PNC) in cesium [Porsev, Beloy, and Drevianko, Phys. Rev. Lett. 102, 181601 (2009)]. We find significant corrections to two nondominating terms coming from the contribution of the core and highly excited states (n>9, the so called tail). When these differences are taken into account the result of Porsev et al., E(PNC)=0.8906(24)×10(-11)i(-Q(W)/N) changes to 0.8977 (40), coming into good agreement with our previous calculations, 0.8980 (45). The interpretation of the PNC measurements in cesium still indicates reasonable agreement with the standard model (1.5σ); however, it gives new constraints on physics beyond it.
16376986
The Next-generation Muon (g-2) Experiment
The muon (g − 2) experiment at the Brookhaven AGS achieved a relative precision on the muon anomalous magnetic moment, a μ , of ±0.54 ppm. The anomaly is sensitive to a wide range of physics beyond the standard model such as supersymmetry, and thus can help constrain the interpretation of any " new physics " found at the Large Hadron Collider. It is desirable to improve the precision of the experiment and of the theoretical (standard-model) value. A new experiment to improve the precision of a μ to ±0.14 ppm is being discussed for Fermilab or J-PARC. The existing precision muon storage ring would be moved to one of these facilities. In parallel, a significant worldwide effort to improve the uncertainty on the standard model value is underway, and over the next several years could produce a significant improvement in the theory uncertainty. c Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.
124123633
SEARCH FOR LORENTZ AND CPT VIOLATION EFFECTS IN MUON SPIN PRECESSION
119417423
Future Muon Dipole Moment Measurements
From the famous experiments of Stern and Gerlach to the present, measurements of magnetic dipole moments, and searches for electric dipole moments of “elementary” particles have played a major role in our understanding of sub-atomic physics. In this talk I discuss the progress on measurements and theory of the magnetic dipole moment of the muon. I also discuss a new proposal to search for a permanent electric dipole moment (EDM) of the muon and put it into the more general context of other EDM searches. These experiments, along with searches for the lepton flavor violating decays μ → e γ and μ − + A → e − + A , provide a path to the high-energy frontier through precision measurements.
13998555
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.
122584301
The Fermilab muon (g−2) project
A proposal to Fermilab, P989, has the goal to improve on the precision of the muon anomalous magnetic moment, a μ = ( g μ − 2 ) / 2 by at least a factor of 4 beyond the 0.54 ppm relative precision obtained in E821 at Brookhaven. The precision storage ring will be moved to Fermilab and installed in a new building. A new 8 GeV/c proton beamline and 3.1 GeV/c muon beamline will be built. The unique capabilities of Fermilab to produce a proton beam with pulses containing ≃ 1 × 10 12 protons at an advantageous duty factor will provide the necessary increase of statistics in a reasonable running time. This new experiment should clarify the apparent difference between the experimental and Standard-Model values of a μ .