G. zu Putlitz

Final report of the E821 muon anomalous magnetic moment measurement at BNL

We present the final report from a series of precision measurements of the muon anomalous magnetic moment, a(mu)=(g-2)/2. The details of the experimental method, apparatus, data taking, and analysis are summarized. Data obtained at Brookhaven National Laboratory, using nearly equal samples of positive and negative muons, were used to deduce a(mu)(Expt)=11659208.0(5.4)(3.3)x10(-10), where the statistical and systematic uncertainties are given, respectively. The combined uncertainty of 0.54 ppm represents a 14-fold improvement compared to previous measurements at CERN. The standard model value for a(mu) includes contributions from virtual QED, weak, and hadronic processes. While the QED processes account for most of the anomaly, the largest theoretical uncertainty, approximate to 0.55 ppm, is associated with first-order hadronic vacuum polarization. Present standard model evaluations, based on e(+)e(-) hadronic cross sections, lie 2.2-2.7 standard deviations below the experimental result.

New bounds from a search for muonium to antimuonium conversion

A new upper limit for the probability of spontaneous muonium to antimuonium conversion was established at P-M (M over bar) less than or equal to 8.3 x 10(-11) (90% C.L.) in 0.1 T magnetic field, which implies consequences for speculative extensions to the standard model. Coupling parameters in R-parity-violating supersymmetry and the mass of a flavor diagonal bileptonic gauge boson can be significantly restricted. A Z(8) model with radiative mass generation through heavy lepton seed and the minimal version of 331 models are disfavored. [S0031-9007(98)08068-5].

Optical investigation of impurities in superfluid4He

This review is devoted to optical studies of foreign particles in superfluid 4He. Starting with single excess electrons, helium ions and metastable helium atoms, various methods for the implantation of these species into the quantum fluid are summarized. Continuing with neutral and charged atoms, molecules, and clusters implantation techniques like laser ablation, gas discharges, or atomic beams are discussed. The implanted particles act as micro-probes for the liquid helium and form complex defect structures—known as bubbles and snowballs. The behavior of the impurities, their defect structures in the liquid, and their optical spectra are discussed. The treatment is mainly focused on the manifold of atoms and ions from nearly all groups of the periodic table of elements which became available for optical experiments in liquid 4He in the recent ten years. It includes theoretical description of the impurities by the standard bubble model (SBM). Extensions and limitations of the SBM are discussed regarding non-radiative transitions and the dynamic Jahn–Teller effect. The review is concluded by a discussion of applications of the presented experimental methods such as spin physics and motion studies in liquid helium.

A high precision magnetometer based on pulsed NMR

Abstract A magnetometer based on pulsed proton magnetic resonance has been developed and constructed. The system will be employed for an accurate measurement of the absolute magnetic field in the region of 1.45 T in a precision experiment on the muons anomalous magnetic moment at the Brookhaven National Laboratory (BNL, USA), where a knowledge of the magnetic field is required with 1 × 10−7 relative accuracy. The performance of the magnetometer has been tested in a large bore superconducting magnet and a precision of one part in 108 was achieved.

Test of CPT and Lorentz invariance from muonium spectroscopy

Following a suggestion of Kostelecký et al. we have evaluated a test of CPT and Lorentz invariance from the microwave spectrosopy of muonium. Precise measurements have been reported for the transition frequencies v 12 and v 34 for ground state muonium in a magnetic field H of 1.7 T, both of which involve principally muon spin flip. These frequencies depend on both the hyperfine interaction and Zeeman effect. Hamiltonian terms beyond the standard model which violate CPT and Lorentz invariance would contribute shifts δv 12 and δv 34. The nonstandard theory indicates that v 12 and v 34 should oscillate with the earth’s sidereal frequency and that δv 12 and δv 34 would be anticorrelated. We find no time dependence in v 12—v 34 at the level of 20 Hz, which is used to set an upper limit on the size of CPT and Lorentz violating parameters.

Atoms and ions in superfluid helium. I: optical spectra of atomic and ionic impurities

Optical spectra of atomic impurities in liquid helium have been investigated. Comparison is made between the wavelength of the free atomic and ionic lines and those in the liquid helium matrix. Simultaneously, the line width and a possible asymmetry is recorded. Presence and absence of radiative transitions depend on the species of the atom implanted in the quantum fluid. The absence of any optical transitions from states lying as low as 1,8 eV below the ionization limit will be explained in this paper.

The Brookhaven muon storage ring magnet

Abstract The muon g-2 experiment at Brookhaven National Laboratory has the goal of determining the muon anomalous g-value a μ (=(g−2)/2) to the very high precision of 0.35 parts per million and thus requires a storage ring magnet with great stability and homogeniety. A superferric storage ring with a radius of 7.11 m and a magnetic field of 1.45 T has been constructed in which the field quality is largely determined by the iron, and the excitation is provided by superconducting coils operating at a current of 5200 A. The storage ring has been constructed with maximum attention to azimuthal symmetry and to tight mechanical tolerances and with many features to allow obtaining a homogenous magnetic field. The fabrication of the storage ring, its cryogenics and quench protection systems, and its initial testing and operation are described.

A MEASUREMENT OF THE 1S-2S TRANSITION FREQUENCY IN MUONIUM

Doppler-free two-photon laser spectroscopy has been employed to measure the 12S12−22S12 transition in the muonium atom (μ+e−). A value of 2 455 529 002(33) (46) MHz has been obtained, which agrees with QED calculations within two standard deviations. The Lamb shift contributions are tested to the level 8×10−3. The corresponding measurements in hydrogen and deuterium using the same apparatus and laser system provide a test of the applied systematic corrections and have verified the systematic error of 46 MHz quoted. The mass of the positive muon has been derived from the isotope shift in this transition and yields a value of 105.65880(29)(43) MeVc2.

Nuclear charge distribution of eight Ca-nuclei by laser spectroscopy

The isotope shift in the Ca-intercombination line withλ=6,573 Å was measured for all isotopes between40Ca and48Ca with the only exception of 47Ca. The combination of the results with muonic x-ray data yields highly accurate values for the changes of the mean square nuclear charge radii. In addition, the nuclear quadrupole moments of the three isotopes41Ca,43Ca and45Ca have been determined from the hyperfine structure splitting of the 4s 4p3P1 state.

The superconducting inflector for the BNL g-2 experiment

The muon g-2 experiment at Brookhaven National Laboratory (BNL) has the goal of determining the muon anomalous magnetic moment, a(mu) (= (g-2)/2), to the very high precision of 0.35 parts per million and thus requires a storage ring magnet with great stability and homogeneity. A super-ferric storage ring has been constructed in which the field is to be known to 0.1 ppm. In addition, a new type of air core superconducting inflector has been developed and constructed, which successfully serves as the injection magnet. The injection magnet cancels the storage ring field, 1.5 T, seen by the entering muon beam very close to the storage ring aperture. At the same time, it gives negligible influence to the knowledge of the uniform main magnetic field in the muon storage region located at just 23 rum away from the beam channel. This was accomplished using a new double cosine theta design for the magnetic field which traps most of the return field, and then surrounding the magnet with a special superconducting sheet which traps the remaining return field. The magnet is operated using a warm-to-cold cryogenic cycle which avoids affecting the precision field of the storage ring. This article describes the design, research development, fabrication process, and final performance of this new type of superconducting magnet