Search results for "C.M.M."
showing 10 items of 1066 documents
The pulsed neutron beam EDM experiment
2018
International audience; We report on the Beam EDM experiment, which aims to employ a pulsed cold neutron beam to search for an electric dipole moment instead of the established use of storable ultracold neutrons. We present a brief overview of the basic measurement concept and the current status of our proof-of-principle Ramsey apparatus.
57Fe,61Ni, and121Sb M�ssbauer study of oxidic spinel ferrites CoxNi5/3?xFeSb1/3O4
1987
Antimony substituted nickel ferrites Co x Ni5/3−xFeSb1/3O4 withx=0,1/3,1,4/3, and 5/3 were prepared by the common ceramic technique, and the single-phase structure was confirmed by x-ray powder diffraction.57Fe Mossbauer spectra were recorded at 4.2 K with and without an applied magnetic fieldHlong=60 kOe in order to determine the cation distribution and the spin structure. Utilizing the cation distributions and the Yafet-Kittel spin structures for B-site Fe3+ ions, derived from Mossbauer experiments the calculated magnetic moments are in excellent agreement with the experimental values at 4.2 K. The existence of Ni2+ ions in crystallographic A-sites was confirmed by61Ni Mossbauer spectrosc…
Disentangling the Mn moments on different sublattices in the half-metallic ferrimagnet Mn3−xCoxGa
2011
Ferrimagnetic Mn3−xCoxGa compounds have been investigated by magnetic circular dichroism in x-ray absorption (XMCD). Compounds with x>0.5 crystallize in the CuHg2Ti structure. A tetragonal distortion of the cubic structure occurs for x≤0.5. For the cubic phase, magnetometry reveals a linearly increasing magnetization of 2x Bohr magnetons per formula unit obeying the generalized Slater–Pauling rule. XMCD confirms the ferrimagnetic character with Mn atoms occupying two different sublattices with antiparallel spin orientation and different degrees of spin localization and identifies the region 0.6<x≤0.8 as most promising for a high spin polarization at the Fermi level. Individual Mn moments on…
Limiting neutrino magnetic moments with Borexino Phase-II solar neutrino data
2017
A search for the solar neutrino effective magnetic moment has been performed using data from 1291.5 days exposure during the second phase of the Borexino experiment. No significant deviations from the expected shape of the electron recoil spectrum from solar neutrinos have been found, and a new upper limit on the effective neutrino magnetic moment of $\mu_{\nu}^{eff}$ $<$ 2.8$\cdot$10$^{-11}$ $\mu_{B}$ at 90\% c.l. has been set using constraints on the sum of the solar neutrino fluxes implied by the radiochemical gallium experiments.Using the limit for the effective neutrino moment, new limits for the magnetic moments of the neutrino flavor states, and for the elements of the neutrino magne…
Measurement of matter-antimatter differences in beauty baryon decays
2017
Differences in the behaviour of matter and antimatter have been observed in $K$ and $B$ meson decays, but not yet in any baryon decay. Such differences are associated with the non-invariance of fundamental interactions under the combined charge-conjugation and parity transformations, known as $C\!P$ violation. Using data from the LHCb experiment at the Large Hadron Collider, a search is made for $C\!P$-violating asymmetries in the decay angle distributions of $\Lambda^0_b$ baryons decaying to $p\pi^-\pi^+\pi^-$ and $p\pi^-K^+K^-$ final states. These four-body hadronic decays are a promising place to search for sources of $C\!P$ violation both within and beyond the Standard Model of particle…
The observation of vibrating pear-shapes in radon nuclei
2019
6 pags., 4 fig.s, 1 tab. -- Open Access funded by Creative Commons Atribution Licence 4.0
New Nuclear Magnetic Moment of Bi209 : Resolving the Bismuth Hyperfine Puzzle
2018
A recent measurement of the hyperfine splitting in the ground state of Li-like ${^{208}\mathrm{Bi}}^{80+}$ has established a ``hyperfine puzzle''---the experimental result exhibits a $7\ensuremath{\sigma}$ deviation from the theoretical prediction [J. Ullmann et al., Nat. Commun. 8, 15484 (2017); J. P. Karr, Nat. Phys. 13, 533 (2017)]. We provide evidence that the discrepancy is caused by an inaccurate value of the tabulated nuclear magnetic moment (${\ensuremath{\mu}}_{I}$) of $^{209}\mathrm{Bi}$. We perform relativistic density functional theory and relativistic coupled cluster calculations of the shielding constant that should be used to extract the value of ${\ensuremath{\mu}}_{I}(^{209…
Electric-Field-Induced Symmetry Breaking of Angular Momentum Distribution in Atoms
2006
We report the experimental observation of alignment to orientation conversion in the 7D_3/2 and 9D_3/2 states of Cs in the presence of an external dc electric field, and without the influence of magnetic fields or atomic collisions. Initial alignment of angular momentum states was created by two-step excitation with linearly polarized laser radiation. The appearance of transverse orientation of angular momentum was confirmed by the observation of circularly polarized light. We present experimentally measured signals and compare them with the results of a detailed theoretical model based on the optical Bloch equations.
Multiple Perspectives on the Stern-Gerlach Experiment
2016
Different or conflicting accounts of the same episode in the history of science may arise from viewing that episode from different perspectives. The metaphor suggests that conflicting accounts can be seen as complementary, constructing a multi-dimensional understanding, if the different perspectives can be coordinated. As an example, I discuss different perspectives on the Stern-Gerlach experiment. In a static interpretation, the SGE has been viewed as an experiment that allows the determination of the magnetic moment of silver atoms. Based on the concept of magnetic momentum arising from orbital angular momentum, the original experiment was designed in 1922 as an experimentum crucis to dec…
Isotropic extragalactic flux from dark matter annihilations: lessons from interacting dark matter scenarios
2016
The extragalactic gamma-ray and neutrino emission may have a contribution from dark matter (DM) annihilations. In the case of discrepancies between observations and standard predictions, one could infer the DM pair annihilation cross section into cosmic rays by studying the shape of the energy spectrum. So far all analyses of the extragalactic DM signal have assumed the standard cosmological model (LambdaCDM) as the underlying theory. However, there are alternative DM scenarios where the number of low-mass objects is significantly suppressed. Therefore the characteristics of the gamma-ray and neutrino emission in these models may differ from LambdaCDM as a result. Here we show that the extr…