No abstract available

[en] The lunar magnetic dipole moment is discussed. It is proposed that, if a primordial core magnetic field existed, it would give rise to a present day nonzero external dipole magnetic field. This conclusion is based on the assumption that the lunar mantle is at least slightly ferromagnetic, and thus would maintain a permanent magnetization after the disappearance of the core magnetic field. By means of a simple mathematical model of the moon, calculations are performed which support this hypothesis

[en] We show that for a composite fermion of sufficiently small radius, the magnetic moment approaches the Dirac value corresponding to the overall charge and mass, regardless of the constituent values. This resolves a recently suggested difficulty in composite models of leptons and quarks. (orig.)

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[en] The reason for the striking imbalance of matter and antimatter in our Universe has yet to be understood. This is the motivation and inspiration to conduct high precision experiments comparing the fundamental properties of matter and antimatter equivalents at lowest energies and with greatest precision. According to theory, the most sensitive tests of CPT invariance are measurements of antihydrogen ground-state hyperfine splitting as well as comparisons of proton and antiproton magnetic moments. Within the BASE collaboration we target the latter. By using a double Penning trap we performed very recently the first direct high precision measurement of the proton magnetic moment. The achieved fractional precision of 3.3 ppb improves the currently accepted literature value by a factor of 2.5. Application of the method to a single trapped antiproton will improve precision of the particles magnetic moment by more than a factor of 1000, thus providing one of the most stringent tests of CPT invariance. In my talk I report on the status and future perspectives of our efforts.

No abstract available

No abstract available

[en] The muon anomalous magnetic dipole moment (MDM) is calculated in the framework of the minimal supersymmetric standard model (MSSM). In this paper, we discuss how the muon MDM depends on the parameters in the MSSM in detail. We show that the contribution of the superparticle loop becomes significant especially when tanβ is large. Numerically, it becomes of order 10^-8 endash 10^-9 in a wide parameter space, which is within the reach of the new Brookhaven E821 experiment. copyright 1996 The American Physical Society

[en] While most quantitative studies of the motion of magnetotactic bacteria rely on the premise that the cells’ magnetic dipole moment is aligned with their direction of motility, this assumption has so far rarely been challenged. Here we use phase contrast microscopy to detect the rotational diffusion of non-motile cells of Magnetospirillum magneticum AMB-1 around their magnetic moment, showing that in this species the magnetic dipole moment is, in fact, not exactly aligned with the cell body axis. From the cell rotational trajectories, we are able to infer the misalignment between cell magnetic moment and body axis with a precision of better than 1°, showing that it is, on average, 6°, and can be as high as 20°. We propose a method to correct for this misalignment, and perform a non-biased measurement of the magnetic moment of single cells based on the analysis of their orientation distribution. Using this correction, we show that magnetic moment strongly correlates with cell length. The existence of a range of misalignments between magnetic moment and cell axis in a population implies that the orientation and trajectories of magnetotactic bacteria placed in external magnetic fields is more complex than generally assumed, and might show some important cell-to-cell differences. (paper)

[en] The magnetic dipole coupling constant (A) for the excited 9S_1/2 level ¹³³Cs isotope has been measured by Doppler-free two-photon fluorescence spectroscopy. The measured hyperfine splitting value of 4377.1(5) MHz is in agreement with previous measurement. Our measured magnetic dipole constant (A) value of 109.7(5) MHz for the upper 9 ²S_1/2 state for the ¹³³Cs isotope is in consistent with the only earlier measured value by femtosecond frequency comb technique in a sequential excitation scheme. (author)