Anomalous magnetic moment of anyons
Gat, G; Gat, Gil; Ray, Rashmi
1994-01-01
The anomalous magnetic moment of anyons is calculated to leading order in a 1/N expansion. It is shown that the gyromagnetic ratio g remains 2 to the leading order in 1/N. This result strongly supports that obtained in \\cite{poly}, namely that g=2 is in fact exact.
Minimal muon anomalous magnetic moment
Biggio, Carla
2014-01-01
We classify all possible one-particle (scalar and fermion) extensions of the Standard Model that can contribute to the anomalous magnetic moment of leptons. We review the cases already discussed in the literature and complete the picture by performing the calculation for a fermionic doublet with hypercharge -3/2. We conclude that, out of the listed possibilities, only two scalar leptoquarks and the pseudoscalar of a peculiar two-Higgs-doublet model could be the responsibles for the muon anomalous magnetic moment discrepancy. Were this the case, this particles could be seen in the next LHC run. To this aim, especially to test the leptoquark hypothesis, we suggest to look for final states with tops and muons.
On the photon anomalous magnetic moment
Villalba, S; Villalba, Selym; Rojas, Hugo Perez
2006-01-01
It is shown that due to radiative corrections a photon having a non vanishing component of its momentum perpendicular to it, bears a non-zero magnetic moment. All modes of propagation of the polarization operator in one loop approximation are discussed and in this field regime the dispersion equation and the corresponding magnetic moment are derived. Near the first thresholds of cyclotron resonance the photon magnetic moment has a peak larger than the electron anomalous magnetic moment. Related to this magnetic moment, the arising of some sort of photon "dynamical mass" and a gyromagnetic ratio are discussed. These latter results might be interesting in an astrophysical context.
Anomalous magnetic moment with heavy virtual leptons
Energy Technology Data Exchange (ETDEWEB)
Kurz, Alexander [Karlsruher Institut fuer Technologie (Germany). Inst. fuer Theoretische Teilchenphysik; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Liu, Tao; Steinhauser, Matthias [Karlsruher Institut fuer Technologie (Germany). Inst. fuer Theoretische Teilchenphysik; Marquard, Peter [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2013-11-15
We compute the contributions to the electron and muon anomalous magnetic moment induced by heavy leptons up to four-loop order. Asymptotic expansion is applied to obtain three analytic expansion terms which show rapid convergence.
Theory of the Muon Anomalous Magnetic Moment
Melnikov, Kirill
2006-01-01
The theory of the muon anomalous magnetic moment is "particle physics in a nutshell" and as such is interesting, exciting and difficult. The current precision of the experimental value for this quantity, improved significantly in the past several years due to experiment E821 at Brookhaven National Laboratory, is so high that a large number of subtle effects not relevant previously, become important for the interpretation of the experimental result. The theory of the muon anomalous magnetic moment is at the cutting edge of current research in particle physics and includes multiloop calculations in both QED and electroweak theory, precision low-energy hadron physics, isospin violations and scattering of light by light. Any deviation between the theoretical prediction and the experimental value might be interpreted as a signal of an as-yet-unknown new physics. This book provides a comprehensive review of the theory of the muon anomalous magnetic moment.
The Anomalous Magnetic Moment of the Muon
Jegerlehner, Friedrich
2008-01-01
This book reviews the present state of knowledge of the anomalous magnetic moment a=(g-2)/2 of the muon. The muon anomalous magnetic moment amy is one of the most precisely measured quantities in elementary particle physics and provides one of the most stringent tests of relativistic quantum field theory as a fundamental theoretical framework. It allows for an extremely precise check of the standard model of elementary particles and of its limitations. Recent experiments at the Brookhaven National Laboratory now reach the unbelievable precision of 0.5 parts per million, improving the accuracy of previous g-2 experiments at CERN by a factor of 14. A major part of the book is devoted to the theory of the anomalous magnetic moment and to estimates of the theoretical uncertainties. Quantum electrodynamics and electroweak and hadronic effects are reviewed. Since non-perturbative hadronic effects play a key role for the precision test, their evaluation is described in detail. After the overview of theory, the exper...
Anomalous magnetic moment and Compton wavelength
Heyrovska, Raji
2004-01-01
The relativistic and quantum theoretical explanations of the magnetic moment anomaly of the electron (or proton) show that it is a complicated function of the fine structure constant. In this work, a simple non-relativistic approach shows that the translational motion of the particle during its spin is responsible for the observed effects.
Anomalous Magnetic Moments and Quark Orbital Angular Momentum
Burkardt, M.; Schnell, G.(University of the Basque Country UPV/EHU, 48080 Bilbao, Spain)
2005-01-01
We derive an inequality for the distribution of quarks with non-zero orbital angular momentum, and thus demonstrate, in a model-independent way, that a non-vanishing anomalous magnetic moment requires both a non-zero size of the target as well as the presence of wave function components with quark orbital angular momentum L_z>0.
Tau anomalous magnetic moment in γγ colliders
Peressutti, Javier; Sampayo, Oscar A.
2012-08-01
We investigate the possibility of setting model independent limits for a nonstandard anomalous magnetic moment aτNP of the tau lepton, in future γγ colliders based on Compton backscattering. For a hypothetical collider we find that, at various levels of confidence, the limits for aτNP could be improved, compared to previous studies based on LEP1, LEP2 and SLD data. We show the results for a realistic range of the center of mass energy of the e+e- collider. As a more direct application, we also present the results of the simulation for the photon collider at the TESLA project.
Muon Anomalous Magnetic Moment in a Supersymmetric U(1)' Model
Barger, V; Langacker, P; Lee, H S; Barger, Vernon; Kao, Chung; Langacker, Paul; Lee, Hye-Sung
2005-01-01
We study the muon anomalous magnetic moment a_\\mu = (g_\\mu - 2)/2 in a supersymmetric U(1)' model. The neutralino sector has extra components from the superpartners of the U(1)' gauge boson and the extra Higgs singlets that break the U(1)' symmetry. The theoretical maximum bound on the lightest neutralino mass is much smaller than that of the Minimal Supersymmetric Standard Model (MSSM) because of the mixing pattern of the extra components. In a U(1)' model where the U(1)' symmetry is broken by a secluded sector (the S-model), tan\\beta is required to be < 3 to have realistic electroweak symmetry breaking. These facts suggest that the a_\\mu prediction may be meaningfully different from that of the MSSM. We evaluate and compare the muon anomalous magnetic moment in this model and the MSSM and discuss the constraints on tan\\beta and relevant soft breaking terms. There are regions of the parameter space that can explain the experimental deviation of a_\\mu from the Standard Model calculation and yield an accept...
Lepton anomalous magnetic moments from twisted mass fermions
Burger, Florian; Jansen, Karl; Petschlies, Marcus
2014-01-01
We present our results for the leading-order hadronic quark-connected contributions to the electron, the muon, and the tau anomalous magnetic moments obtained with four dynamical quarks. Performing the continuum limit and an analysis of systematic effects, full agreement with phenomenological results is found. To estimate the impact of omitting the quark-disconnected contributions to the hadronic vacuum polarisation we investigate them on one of the four-flavour ensembles. Additionally, the light quark contributions on the four-flavour sea are compared to the values obtained for $N_f=2$ physically light quarks. In the latter case different methods to fit the hadronic vacuum polarisation function are tested.
Improved Measurement of the Positive Muon Anomalous Magnetic Moment
Brown, H N; Carey, R M; Cushman, P B; Danby, G T; Debevec, P T; Deng, H; Deninger, W J; Dhawan, S K; Druzhinin, V P; Duong, L; Earle, W; Efstathiadis, E F; Fedotovich, G V; Farley, Francis J M; Giron, S; Gray, F; Grosse-Perdekamp, M; Grossmann, A; Haeberlen, U; Hare, M; Hazen, E S; Hertzog, D W; Hughes, V W; Iwasaki, M; Jungmann, Klaus; Kawall, D; Kawamura, M; Khazin, B I; Kindem, J; Krienen, F; Kronkvist, I J; Larsen, R; Lee, Y Y; Logashenko, I B; McNabb, R; Meng, W; Mi, J; Miller, J P; Morse, W M; Onderwater, Gerco; Orlov, Yu F; Ozben, C; Polly, C; Pai, C; Paley, J M; Pretz, J; Prigl, R; zu Putlitz, Gisbert; Redin, S I; Rind, O; Roberts, B L; Ryskulov, N M; Sedykh, S N; Semertzidis, Y K; Shatunov, Yu M; Solodov, E P; Sossong, M; Steinmetz, A; Sulak, Lawrence R; Timmermans, C; Trofimov, A V; Urner, D; Von Walter, P; Warburton, D; Winn, D; Yamamoto, A; Zimmerman, D
2000-01-01
A new measurement of the positive muon's anomalous magnetic moment has been made at the Brookhaven Alternating Gradient Synchrotron using the direct injection of polarized muons into the superferric storage ring. The angular frequency difference omega_{a} between the angular spin precession frequency omega_{s} and the angular orbital frequency omega_{c} is measured as well as the free proton NMR frequency omega_{p}. These determine R = omega_{a} / omega_{p} = 3.707~201(19) times 10^{-3}. With mu_{mu} / mu_{p} = 3.183~345~39(10) this gives a_{mu^+} = 11~659~191(59) times 10^{-10} (pm 5 ppm), in good agreement with the previous CERN and BNL measurements for mu^+ and mu^-, and with the standard model prediction.
Precision Measurement of the Anomalous Magnetic Moment of the Muon
Ozben, C S
2002-01-01
The muon g-2 experiment at Brookhaven National Laboratory measures the anomalous magnetic moment of the muon, $a_\\mu$, very precisely. This measurement tests the Standard Model theory. The analysis for the data collected in 2000 (a $\\mu^+$ run) is completed and the accuracy on $a_\\mu$ is improved to 0.7 ppm, including statistical and systematic errors. The data analysis was performed blindly between the precession frequency and the field analysis groups in order to prevent a possible bias in the $a_\\mu$ result. The observed difference between the theory and our most recent experimental result is quite important for further studies of the Standard Model theory. In 2001, we ran for the first time with $\\mu^-$ and the analysis of this data will provide $a_\\mu$ with similar statistical power.
Rosenbluth scattering and Pauli's approach to anomalous magnetic moments
International Nuclear Information System (INIS)
In standard QED particle interactions are evaluated using minimal coupling, coupling the particles solely through their (electric monopole) charges. The Direc Hamiltonian is used to describe the interaction of a single spin-1/2 particle with an electromagnetic field. Pauli suggested the addition of a further gauge-invariant term to the Dirac Hamiltonian where the coupling constant for this extra term should not be directly linked to the particle's electric charge. We study some of the effects of this additional term and show that for the scattering of electrons off protons, the first-order Pauli-Dirac analysis has at least as good agreement with experiment as previous analyses based on the Dirac Hamiltonian. We show that Rosenbluth used the incorrect sign on the anomalous magnetic moment of the proton. (author)
New Physics Contributions to the Muon Anomalous Magnetic Moment
Queiroz, Farinaldo S
2014-01-01
We consider the contributions of individual new particles to the anomalous magnetic moment of the muon, utilizing the generic framework of simplified models. We also present analytic results for all possible one-loop contributions, allowing easy application of these results for more complete models which predict more than one particle capable of correcting the muon magnetic moment. Additionally, we provide a Mathematica code to allow the reader straightforwardly compute any 1-loop contribution. Furthermore, we derive bounds on each new particle considered, assuming either the absence of other significant contributions to $a_\\mu$ or that the anomaly has been resolved by some other mechanism. In summary we found the following particles capable of explaining the current discrepancy, assuming unit couplings: $2$TeV ($0.3$TeV) neutral scalar with pure scalar (chiral) couplings, $4$TeV doubly charged scalar with pure pseudoscalar coupling, $0.3-1$TeV neutral vector boson depending on what couplings are used (vector...
Progress in analytical calculations for the anomalous magnetic moment of the muon
Energy Technology Data Exchange (ETDEWEB)
Baikov, P.A. [Moscow State Univ. (Russian Federation). Skobeltsyn Inst. of Nuclear Physics; Maier, A. [Technische Univ. Muenchen (Germany). Physik Dept. T31; Marquard, P. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2013-11-15
We present results for certain classes of diagrams contributing to the anomalous magnetic moment of the muon at five-loop order. Our method is based on first constructing an approximating function for the vacuum polarization function of the photon at four loop order which later can be numerically integrated to obtain the anomalous magnetic moment of the muon.
Kisel, V V; Red'kov, V M
2011-01-01
Tensor 50-component form of the first order relativistic wave equation for a particle with spin 2 and anomalous magnetic moment is extended to the case of an arbitrary curved space-time geometry. An additional parameter considered in the presence of only electromagnetic field as related to anomalous magnetic moment, turns to determine additional interaction terms with external geometrical background through Ricci R_{kl} and Riemann R_{klmn} tensors.
Composite Higgs Models, Technicolor and The Muon Anomalous Magnetic Moment
Doff, A
2015-01-01
We revisit the muon magnetic moment (g-2) in the context of Composite Higgs models and Technicolor, and provide general analytical expressions for computing the muon magnetic moment stemming from new fields such as, neutral gauge bosons, charged gauge bosons, neutral scalar, charged scalars, and exotic charged leptons type of particles. Under general assumptions we assess which particle content could address the $g-2_{\\mu}$ excess. Moreover, we take a conservative approach and derive stringent limits on the particle masses in case the anomaly is otherwise resolved and comment on electroweak and collider bounds. Lastly, for concreteness we apply our results to a particular Technicolor model.
Anomalous Temperature Dependence of Magnetic Moment in Monodisperse Antiferromagnetic Nanoparticles
Gillaspie, Dane; Gu, B.; Wang, W.; Shen, J.
2005-03-01
1 Condensed Matter Sciences Division, Oak Ridge National Laboratory*, TN 37831 2 Department of Physics and Astronomy, The University of Tennessee, TN 37996 3 Environmental Sciences Division, Oak Ridge National Laboratory*, TN 37831 Recent experiments [1] and theory [2] from AFM nanoparticles showed that they exhibit sizable net magnetization, which increases with increasing temperature. In order to further understand such peculiar temperature dependence, we have measured the magnetic properties of monodisperse hematite (α-Fe2O3) nanoparticles, grown using a microemulsion precipitation technique, which minimizes the impact of the particle moment distribution on the measured properties of the samples. Our measured results indicate that the net magnetization of these nanoparticles, when small, indeed increases linearly with increasing temperature. This is in sharp contrast to the bulk-like behavior of α-Fe2O3, which was observed in particles with size larger than 120 nm. [1] M. Seehra et al, Phys. Rev. B 61, 3513 (2000) [2] S. Mørup, C. Frandsen, Phys. Rev. Lett. 92, 217201 (2004) *Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Dept. of Energy under contract DE-AC05-00OR22725
Prediction of the anomalous magnetic moment of nucleon from the nucleon anomaly
Lin, Y C
1995-01-01
We construct the effective anomaly lagrangian involving nucleons and photons by using current-current coupling method. The contribution of this lagrangian to the anomalous magnetic moment of nucleon is purely isovector. The anomalous magnetic moment of proton, \\kappa_P, can be calculated from the this lagrangian and it is found to be \\kappa_P^{Theor.} = 1.77, which is in excellent agreement with the experimental value \\kappa_P^{Exp.} = 1.79. While the case of neutron, \\kappa_N^{Theor.} = -2.58 as compared to \\kappa_N^{Exp.} =-1.91, is less satisfactory, but the sign is correct.
Energy Technology Data Exchange (ETDEWEB)
Gisin, B V [Department of Electrical Engineering - Physical Electronics, Faculty of Engineering, Tel-Aviv University Tel-Aviv 69978 (Israel)
2002-08-01
We consider the anomalous magnetic moment from an 'optical viewpoint' using an analogy between the motion of a particle with a magnetic moment in a magnetic field and the propagation of an optical pulse through an electro-optical crystal in an electric field. We show that an optical experiment similar to electron magnetic resonance is possible in some electro-optical crystals possessing the Faraday effect. This phenomenon is described by an analogue of the Pauli equation extracted from the Maxwell equation in the slowly varied amplitude approximation. In such an experiment the modulation by rotating fields plays a significant role. From the optical viewpoint the modulation assumes introducing the concept of a point rotation frame with the rotation axis at every point originated from the concept of the optical indicatrix (index ellipsoid). We discuss the connection between the non-classical transformation by transition from one such frame to another and an anomalous magnetic moment.
Leading-order hadronic contributions to the electron and tau anomalous magnetic moments
Burger, Florian; Jansen, Karl; Petschlies, Marcus
2015-01-01
The leading hadronic contributions to the anomalous magnetic moments of the electron and the $\\tau$-lepton are determined by a four-flavour lattice QCD computation with twisted mass fermions. The continuum limit is taken and systematic uncertainties are quantified. Full agreement with results obtained by phenomenological analyses is found.
Leading-order hadronic contributions to the electron and tau anomalous magnetic moments
Energy Technology Data Exchange (ETDEWEB)
Burger, Florian; Hotzel, Grit [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Petschlies, Marcus [The Cyprus Institute, Nicosia (Cyprus)
2015-01-15
The leading hadronic contributions to the anomalous magnetic moments of the electron and the τ-lepton are determined by a four-flavour lattice QCD computation with twisted mass fermions. The continuum limit is taken and systematic uncertainties are quantified. Full agreement with results obtained by phenomenological analyses is found.
Final report of the E821 muon anomalous magnetic moment measurement at BNL
Bennett, GW; Bousquet, B; Brown, HN; Bunce, G; Carey, RM; Cushman, P; Danby, GT; Debevec, PT; Deile, M; Deng, H; Deninger, W; Dhawan, SK; Druzhinin, VP; Duong, L; Efstathiadis, E; Farley, FJM; Fedotovich, GV; Giron, S; Gray, FE; Grigoriev, D; Grosse-Perdekamp, M; Grossmann, A; Hare, MF; Hertzog, DW; Huang, [No Value; Hughes, VW; Iwasaki, M; Jungmann, Klaus-Peter; Kawall, D; Kawamura, M; Khazin, BI; Kindem, J; Krienen, F; Kronkvist, [No Value; Lam, A; Larsen, R.; Lee, YY; Logashenko, [No Value; McNabb, R; Meng, W; Mi, J; Miller, JP; Mizumachi, Y; Morse, WM; Nikas, D; Onderwater, Gerco; Orlov, Y; Ozben, CS; Paley, JM; Peng, Q; Polly, CC; Pretz, J; Prigl, R; Putlitz, GZ; Qian, T; Redin, SI; Rind, O; Roberts, BL; Ryskulov, N; Sedykh, S; Semertzidis, YK; Shagin, P; Shatunov, YM; Sichtermann, EP; Solodov, E; Sossong, M; Steinmetz, A; Sulak, LR; Timmermans, C; Trofimov, A; Urner, D; von Walter, P; Warburton, D; Winn, D; Yamamoto, A; Zimmerman, D
2006-01-01
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 positi
Pitschmann, M.; A. N. Ivanov
2012-01-01
The Dirac equation for charged and neutral fermions with anomalous magnetic moments is solved in a uniform magnetic field. We find the relativistic wave functions and energy spectra. In the non-relativistic limit the wave functions and energy spectra of charged fermions agree with the known solutions of the Schroedinger equation.
Bubnov, Andrey; Gubina, Nadezda; Zhukovsky, Vladimir
2016-05-01
We study vacuum polarization effects in the model of Dirac fermions with additional interaction of an anomalous magnetic moment with an external magnetic field and fermion interaction with an axial-vector condensate. The proper time method is used to calculate the one-loop vacuum corrections with consideration for different configurations of the characteristic parameters of these interactions.
Elias, V; Elias, Victor; Sprague, Kevin
1998-01-01
We consider the contribution of fermion-antifermion condensates to the anomalous magnetic moment of a fermion in a vacuum in which such condensates exist. The real part of the condensate contribution to the anomalous magnetic moment is shown to be zero. A nonzero imaginary part is obtained below the kinematic threshold for intermediate fermion-antifermion pairs. The calculation is shown to be gauge-parameter independent provided a single fermion mass characterizes both the fermion propagator and condensate-sensitive contributions, suggestive of a dynamically-generated fermion mass. The nonzero imaginary part is then argued to correspond to the kinematic production of the intermediate-state Goldstone bosons anticipated from a chiral-noninvariant vacuum. Finally, speculations are presented concerning the applicability of these results to quark electromagnetic properties.
N=2-Maxwell-Chern-Simons Model with Anomalous Magnetic Moment Coupling via Dimensional Reduction
Christiansen, H R; Helayël-Neto, José A; Mansur, L R; Nogueira, A L M A
1999-01-01
An N=1--supersymmetric version of the Cremmer-Scherk-Kalb-Ramond model with non-minimal coupling to matter is built up both in terms of superfields and in a component-field formalism. By adopting a dimensional reduction procedure, the N=2--D=3 counterpart of the model comes out, with two main features: a genuine (diagonal) Chern-Simons term and an anomalous magnetic moment coupling between matter and the gauge potential.
Leading-order hadronic contributions to the lepton anomalous magnetic moments from the lattice
Burger, Florian; Feng, Xu; Jansen, Karl; Petschlies, Marcus; Pientka, Grit; Renner, Dru B.
2016-04-01
The hadronic leading-order (hlo) contribution to the lepton anomalous magnetic moments alhlo of the Standard Model leptons still accounts for the dominant source of the uncertainty of the Standard Model estimates. We present the results of an investigation of the hadronic leading order anomalous magnetic moments of the electron, muon and tau lepton from first principles in twisted mass lattice QCD. With lattice data for multiple pion masses in the range 230MeV ≲ mPS ≲ 490 MeV, multiple lattice volumes and three lattice spacings we perform the extrapolation to the continuum and to the physical pion mass and check for all systematic uncertainties in the lattice calculation. As a result we calculate alhlo for the three Standard Model leptons with controlled statistical and systematic error in agreement with phenomenological determinations using dispersion relations and experimental data. In addition, we also give a first estimate of the hadronic leading order anomalous magnetic moments from simulations directly at the physical value of the pion mass.
Leading-order hadronic contributions to the lepton anomalous magnetic moments from the lattice
Energy Technology Data Exchange (ETDEWEB)
Burger, Florian [OakLabs GmbH, Hennigsdorf (Germany); Feng, Xu [Columbia University, New York, NY (United States). Dept. of Physics; Jansen, Karl [DESY Zeuthen (Germany). NIC; Petschlies, Marcus [Bonn Univ. (Germany). Inst. fuer Strahlen- und Kernphysik; Pientka, Grit [Humboldt-Univ. Berlin (Germany). Inst. fuer Physik; Renner, Dru B. [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
2015-11-15
The hadronic leading-order (hlo) contribution to the lepton anomalous magnetic moments a{sup hlo}{sub l} of the Standard Model leptons still accounts for the dominant source of the uncertainty of the Standard Model estimates. We present the results of an investigation of the hadronic leading order anomalous magnetic moments of the electron, muon and tau lepton from first principles in twisted mass lattice QCD. With lattice data for multiple pion masses in the range 230 MeV
Kruglov, S I
2001-01-01
The matrix, 8-component Dirac-like form of P-odd equations for boson fields of spins 1 and 0 are obtained and the GL(2,c) symmetry group of equations is derived. We found exact solutions of the field equation for vector particles with arbitrary electric and magnetic moments in external constant and uniform electromagnetic fields. The differential probability of pair production of vector particles with the EDM and AMM by an external constant and uniform electromagnetic field has been found using the exact solutions. We have calculated the imaginary and real parts of the electromagnetic field Lagrangian that takes into account the vacuum polarization of vector particles.
Kruglov, S. I.
2001-01-01
The matrix, 8-component Dirac-like form of P-odd equations for boson fields of spins 1 and 0 are obtained and the GL(2,c) symmetry group of equations is derived. We found exact solutions of the field equation for vector particles with arbitrary electric and magnetic moments in external constant and uniform electromagnetic fields. The differential probability of pair production of vector particles with the EDM and AMM by an external constant and uniform electromagnetic field has been found usi...
Directory of Open Access Journals (Sweden)
Abyaneh Mehran Zahiri
2012-12-01
Full Text Available We give a short overview of the theory of the muon anomalous magnetic moment with emphasis on the hadronic light-by-light and the pion loop contribution. We explain the difference between the hidden local symmetry and full VMD pion loop and discuss leading logarithms in the anomalous sector of 2-flavour chiral perturbation theory.
Bijnens, Johan
2012-01-01
We give a short overview of the theory of the muon anomalous magnetic moment with emphasis on the hadronic light-by-light and the pion loop contribution. We explain the difference between the hidden local symmetry and full VMD pion loop and discuss leading logarithms in the anomalous sector of 2-flavour chiral perturbation theory.
Influence of the electron's anomalous magnetic dipole moment on high-atomic number atoms
International Nuclear Information System (INIS)
Super heavy atoms ( Z > 100 ) are usually studied in the context of the so-called Quantum Electrodynamics of Strong Fields. In this theory the problem of the singularity in the electron energy whenever Z > 137 is overcome. This is done by considering the finite size of the nucleus and leads to interesting phenomena, such as the spontaneous production of positrons. Here, we show that, taking into account the contribution from the Anomalous Magnetic Dipole Moment of the electron ( by means of an effective theory ), within a point nucleus model, is a sufficient condition to obtain regular wave functions and physically acceptable energy values for Z > 137. (author)
Charged spin half particle with anomalous magnetic moment in a plane wave field
Energy Technology Data Exchange (ETDEWEB)
Vaidya, Arvind Narayan [Universidade Federal do Rio de Janeiro, RJ (Brazil); Silva Filho, Pedro Barbosa da [Universidade Federal da Paraiba, Cajazeiras, PB (Brazil)
2000-07-01
Full text follows: The Dirac-Pauli equation for a charged spin half particle with anomalous magnetic moment in the presence of a plane wave external electromagnetic field is solved by an algebraic method and the solutions are shown to be simply related to the free particle ones.We also discuss the relationship of our results with the work of other authors. We show that our solutions are equivalent to those of Chakrabarti. We also show that the different results of Barut and Duru are in error. (author)
Topcolour-assisted technicolour models and the muon anomalous magnetic moment
International Nuclear Information System (INIS)
We discuss and estimate the contributions of the new particles predicted by topcolour-assisted technicolour (TC2) models to the muon anomalous magnetic moment aμ. Our results show that the contributions of pseudo-Goldstone bosons are very small and can be safely ignored. The main contributions come from the ETC gauge boson xμ and topcolour gauge boson Z'. If we demand that the mass of Z' is consistent with other experimental constraints, its contributions are smaller than that of xμ. With reasonable values of the parameters in TC2 models, the observed BNL results for aμ could be explained. (author)
Lattice Calculation of Hadronic Light-by-Light Contribution to the Muon Anomalous Magnetic Moment
Blum, Thomas; Hayakawa, Masashi; Izubuchi, Taku; Jin, Luchang; Lehner, Christoph
2016-01-01
The quark-connected part of the hadronic light-by-light scattering contribution to the muon's anomalous magnetic moment is computed using lattice QCD with chiral fermions. We report several significant algorithmic improvements and demonstrate their effectiveness through specific calculations which show a reduction in statistical errors by more than an order of magnitude. The most realistic of these calculations is performed with a near-physical, $171$ MeV pion mass on a $(4.6\\;\\mathrm{fm})^3$ spatial volume using the $32^3\\times 64$ Iwasaki+DSDR gauge ensemble of the RBC/UKQCD Collaboration.
Muon Anomalous Magnetic Moment and Gauge Symmetry in the Standard Model
Tsai, Er-Cheng
2014-01-01
No gauge invariant regularization is available for the perturbative calculation of the standard model. One has to add finite counter terms to restore gauge symmetry for the renormalized amplitudes. The muon anomalous magnetic moment can be accurately measured but the experimental result does not entirely agree with the theoretical calculation from the standard model. This paper is to compute the contributions to the muon gyromagnetic ratio $g_{\\mu}$ due to the finite counter terms. The result obtained is found to be far from sufficient to explain the discrepancy between theory and experiment.
Inverted effective SUSY with combined Z' and gravity mediation, and muon anomalous magnetic moment
Kim, Jihn E.
2012-01-01
Effective supersymmetry(SUSY) where stop is the lightest squark may run into a two-loop tachyonic problem in some Z' mediation models. In addition, a large A term or/and a large stop mass are needed to have about a 126 GeV Higgs boson with three families of quarks and leptons. Thus, we suggest an inverted effective SUSY(IeffSUSY) where stop mass is larger compared to those of the first two families. In this case, it is possible to have a significant correction to the anomalous magnetic moment...
Higgs mass and muon anomalous magnetic moment in the U(1) extended MSSM
Endo, Motoi; Iwamoto, Sho; Nakayama, Kazunori; Yokozaki, Norimi
2011-01-01
We study phenomenological aspects of the MSSM with extra U(1) gauge symmetry. We find that the lightest Higgs boson mass can be increased up to 125GeV without introducing a large SUSY scale or large A-terms, in the frameworks of the CMSSM and gauge mediated SUSY breaking (GMSB) models. This scenario can simultaneously explain the discrepancy of the muon anomalous magnetic moment (muon g-2) at the 1 sigma / 2 sigma level for U(1)-extended CMSSM / GMSB models. In the CMSSM case, the dark matter abundance can also be explained.
N=2-Maxwell-Chern-Simons model with anomalous magnetic moment coupling via dimensional reduction
Energy Technology Data Exchange (ETDEWEB)
Christiansen, H.R.; Cunha, M.S.; Helayel Neto, Jose A.; Manssur, L.R.U; Nogueira, A.L.M.A. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Dept. de Campos e Particulas
1998-02-01
An N=1-supersymmetric version of the Cremmer-Scherk-Kalb-Ramond model with non-minimal coupling to matter is built up both in terms of superfields and in a component field formalism. By adopting a dimensional reduction procedure, the N=2-D=3 counterpart of the model comes out, with two main features: a genuine (diagonal) Chern-Simons term and an anomalous magnetic moment coupling between matter and the gauge potential. (author) 14 refs.; e-mail: hugo, macony, helayel, leon, nogue at cat.cbpf.br
Electric and anomalous magnetic dipole moments of the muon in the MSSM
International Nuclear Information System (INIS)
We study the electric dipole moment (EDM) and the anomalous magnetic dipole moment (MDM) of the muon in the CP-violating Minimal Supersymmetric extension of the Standard Model (MSSM). We take into account the contributions from the chargino- and neutralino-mediated one-loop graphs and the dominant two-loop Higgs-mediated Barr-Zee diagrams. We improve earlier calculations by incorporating CP-violating Higgs-boson mixing effects and the resummed threshold corrections to the Yukawa couplings of the charged leptons as well as that of the bottom quark. The analytic correlation between the muon EDM and MDM is explicitly presented at one- and two-loop levels and, through several numerical examples, we illustrate its dependence on the source of the dominant contributions. We have implemented the analytic expressions for the muon EDM and MDM in an updated version of the public code CPsuperH2.0.
Electric and anomalous magnetic dipole moments of the muon in the MSSM
Cheung, Kingman; Lee Jae Sik
2009-01-01
We study the electric dipole moment (EDM) and the anomalous magnetic dipole moment (MDM) of the muon in the CP-violating Minimal Supersymmetric extension of the Standard Model (MSSM). We take into account the contributions from the chargino- and neutralino-mediated one-loop graphs and the dominant two-loop Higgs-mediated Barr-Zee diagrams. We improve earlier calculations by incorporating CP-violating Higgs-boson mixing effects and the resummed threshold corrections to the Yukawa couplings of the charged leptons as well as that of the bottom quark. The analytic correlation between the muon EDM and MDM is explicitly presented at one- and two-loop levels and, through several numerical examples, we illustrate its dependence on the source of the dominant contributions. We have implemented the analytic expressions for the muon EDM and MDM in an updated version of the public code CPsuperH2.0.
Leading-order hadronic contributions to the lepton anomalous magnetic moments from the lattice
Burger, Florian; Jansen, Karl; Petschlies, Marcus; Pientka, Grit; Renner, Dru B
2015-01-01
The hadronic leading-order (hlo) contribution to the lepton anomalous magnetic moments $a_l^\\mathrm{hlo}$ of the Standard Model leptons still accounts for the dominant source of the uncertainty of the Standard Model estimates. We present the results of an investigation of the hadronic leading order anomalous magnetic moments of the electron, muon and tau lepton from first principles in twisted mass lattice QCD. With lattice data for multiple pion masses in the range $230 \\mathrm{~MeV} \\lesssim m_{PS} \\lesssim 490 \\mathrm{~MeV}$, multiple lattice volumes and three lattice spacings we perform the extrapolation to the continuum and to the physical pion mass and check for all systematic uncertainties in the lattice calculation. As a result we calculate $a_{l}^\\mathrm{hlo}$ for the three Standard Model leptons with controlled statistical and systematic error in agreement with phenomenological determinations using dispersion relations and experimental data. In addition, we also give a first estimate of the hadronic...
Electron contribution to the muon anomalous magnetic moment at four loops
Energy Technology Data Exchange (ETDEWEB)
Kurz, Alexander [Karlsruher Institut fuer Technologie (Germany). Inst. fuer Theoretische Teilchenphysik; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Liu, Tao [Alberta Univ., Edmonton, AB (Canada). Dept. of Physics; Marquard, Peter [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Smirnov, Alexander V. [Moscow State Univ. (Russian Federation). Scientific Research Computing Center; Smirnov, Vladimir A. [Moscow State Univ. (Russian Federation). Skobeltsyn Inst. of Nuclear Physics; Humboldt-Universitaet, Berlin (Germany). Inst. fuer Mathematik; Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Steinhauser, Matthias [Karlsruher Institut fuer Technologie (Germany). Inst. fuer Theoretische Teilchenphysik
2016-02-15
We present results for the QED contributions to the anomalous magnetic moment of the muon containing closed electron loops. The main focus is on perturbative corrections at four-loop order where the external photon couples to the external muon. Furthermore, all four-loop contributions involving simultaneously a closed electron and tau loop are computed. In combination with our recent results on the light-by-light-type corrections the complete four-loop electron-loop contribution to the anomalous magnetic moment of the muon has been obtained with an independent calculation. Our calculation is based on an asymptotic expansion in the ratio of the electron and the muon mass and shows the importance of higher order terms in this ratio. We perform a detailed comparison with results available in the literature and find good numerical agreement. As a by-product we present analytic results for the on-shell muon mass and wave function renormalization constants at three-loop order including massive closed electron and tau loops, which we also calculated using the method of asymptotic expansion.
Series expansion of the photon self-energy in QED and the photon anomalous magnetic moment
Rojas, H Perez; Chavez, S Villalba
2008-01-01
We start from the analytical expression of the eigenvalues $\\kappa^{(i)}$ of the photon self-energy tensor in an external constant magnetic field $B$ calculated by Batalin Shabad in the Furry representation, and in the one-loop approximation. We expand in power series of the external field and in terms of the squared photon transverse momentum $z_2$ and (minus) transverse energy $z_1=k^2-z_2$, in terms of which are expressed $\\kappa^{(i)}$. A general expression is given for the photon anomalous magnetic moment $\\mu_{\\gamma}>0$ in the region of transparency, below the first threshold for pair creation, and it is shown that it is positive, i.e. paramagnetic. The results of the numerical calculation for $\\mu_{\\gamma}>0$ are displayed in a region close to the threshold.
Relativistic energy correction of the hydrogen atom with an anomalous magnetic moment
International Nuclear Information System (INIS)
The electron is known to possess an anomalous magnetic moment, which interacts with the gradient of the electric field. This makes it necessary to compute its effects on the energy spectrum. Even though the Coulomb Dirac equation can be solved in closed form, this is no longer possible when the anomalous magnetic moment is included. In fact the interaction due to this term is so strong that it changes the domain of the Hamiltonian. From a differential equation point of view, the anomalous magnetic moment term is strongly singular near the origin. As usual, one has to resort to perturbation theory. This, however, only makes sense if the eigenvalues are stable. To prove stability is therefore a challenge one has to face before actually computing the energy shifts. The first stability results in this line were shown by Behncke for angular momenta κ≥3, because the eigenfunctions of the unperturbed Hamiltonian decay fast enough near the origin. He achieved this by decoupling the system and then using the techniques available for second order differential equations. Later, Kalf and Schmidt extended Behncke's results basing their analysis on the Pruefer angle technique and a comparison result for first order differential equations. The Pruefer angle method is particularly useful because it shows a better stability and because it obeys a first order differential equation. Nonetheless, Kalf and Schmidt had to exclude some coupling constants for κ>0. This I believe is an artefact of their method. In this study, I make increasing use of asymptotic integration, a method which is rather well adapted to perturbation theory and is known to give stability results to any level of accuracy. Together with the Pruefer angle technique, this lead to a more general stability result and even allows for an energy shifts estimate. Hamiltonians traditionally treated in physics to describe the spin-orbit effect are not self adjoint i.e. they are not proper observables in quantum
Relativistic energy correction of the hydrogen atom with an anomalous magnetic moment
Energy Technology Data Exchange (ETDEWEB)
Ambogo, David Otieno
2015-07-15
The electron is known to possess an anomalous magnetic moment, which interacts with the gradient of the electric field. This makes it necessary to compute its effects on the energy spectrum. Even though the Coulomb Dirac equation can be solved in closed form, this is no longer possible when the anomalous magnetic moment is included. In fact the interaction due to this term is so strong that it changes the domain of the Hamiltonian. From a differential equation point of view, the anomalous magnetic moment term is strongly singular near the origin. As usual, one has to resort to perturbation theory. This, however, only makes sense if the eigenvalues are stable. To prove stability is therefore a challenge one has to face before actually computing the energy shifts. The first stability results in this line were shown by Behncke for angular momenta κ≥3, because the eigenfunctions of the unperturbed Hamiltonian decay fast enough near the origin. He achieved this by decoupling the system and then using the techniques available for second order differential equations. Later, Kalf and Schmidt extended Behncke's results basing their analysis on the Pruefer angle technique and a comparison result for first order differential equations. The Pruefer angle method is particularly useful because it shows a better stability and because it obeys a first order differential equation. Nonetheless, Kalf and Schmidt had to exclude some coupling constants for κ>0. This I believe is an artefact of their method. In this study, I make increasing use of asymptotic integration, a method which is rather well adapted to perturbation theory and is known to give stability results to any level of accuracy. Together with the Pruefer angle technique, this lead to a more general stability result and even allows for an energy shifts estimate. Hamiltonians traditionally treated in physics to describe the spin-orbit effect are not self adjoint i.e. they are not proper observables in quantum
MeV scale leptonic force for cosmic neutrino spectrum and muon anomalous magnetic moment
Araki, Takeshi; Ota, Toshihiko; Sato, Joe; Shimomura, Takashi
2015-01-01
Characteristic patterns of cosmic neutrino spectrum reported by the IceCube collaboration and long-standing inconsistency between theory and experiment in muon anomalous magnetic moment are simultaneously explained by an extra leptonic force mediated by a gauge field with a mass of the MeV scale. With different assumptions for redshift distribution of cosmic neutrino sources, diffuse neutrino flux is calculated with the scattering between cosmic neutrino and cosmic neutrino background through the new leptonic force. Our analysis sheds light on a relation among lepton physics at the three different scales, PeV, MeV, and eV, and provides possible clues to the distribution of sources of cosmic neutrino and also to neutrino mass spectrum.
Four-Flavour Leading Hadronic Contribution To The Muon Anomalous Magnetic Moment
Burger, Florian; Hotzel, Grit; Jansen, Karl; Petschlies, Marcus; Renner, Dru B
2013-01-01
We present a four-flavour lattice calculation of the leading-order hadronic vacuum polarisation contribution to the anomalous magnetic moment of the muon, $a_{\\mu}^{\\rm hvp}$, arising from quark-connected Feynman graphs. It is based on ensembles featuring $N_f=2+1+1$ dynamical twisted mass fermions generated by the European Twisted Mass Collaboration (ETMC). Several light quark masses are used in order to yield a controlled extrapolation to the physical pion mass. We employ three lattice spacings to examine lattice artefacts and several different volumes to check for finite-size effects. Including the complete first two generations of quarks allows for a direct comparison with phenomenological determinations of $a_{\\mu}^{\\rm hvp}$. Our final result involving an estimate of the systematic uncertainty $$a_{\\mathrm{\\mu}}^{\\rm hvp} = 6.74(21)(18) \\cdot 10^{-8}$$ shows a good overall agreement with these computations.
Four-flavour leading hadronic contribution to the muon anomalous magnetic moment
Energy Technology Data Exchange (ETDEWEB)
Burger, Florian; Hotzel, Grit [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Feng, Xu [KEK National High Energy Physics, Tsukuba (Japan); Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Cyprus Univ. Nicosia (Cyprus). Dept. of Physics; Petschlies, Marcus [The Cyprus Institute, Nicosia (Cyprus); Renner, Dru B. [Jefferson Lab, Newport News, VA (United States)
2013-11-15
We present a four-flavour lattice calculation of the leading-order hadronic vacuum polarisation contribution to the anomalous magnetic moment of the muon, a{sup hvp}{sub {mu}}, arising from quark-connected Feynman graphs. It is based on ensembles featuring N{sub f}=2+1+1 dynamical twisted mass fermions generated by the European Twisted Mass Collaboration (ETMC). Several light quark masses are used in order to yield a controlled extrapolation to the physical pion mass. We employ three lattice spacings to examine lattice artefacts and several different volumes to check for finite-size effects. Including the complete first two generations of quarks allows for a direct comparison with phenomenological determinations of a{sup hvp}{sub {mu}}. Our final result involving an estimate of the systematic uncertainty a{sup hvp}{sub {mu}}=6.74(21)(18) x 10{sup -8} shows a good overall agreement with these computations.
Benayoun, Maurice; Blum, Tom; Caprini, Irenel; Colangelo, Gilberto; Czyż, Henryk; Denig, Achim; Dominguez, Cesareo A; Eidelman, Simon; Fischer, Christian S; Gauzzi, Paolo; Guo, Yuping; Hafner, Andreas; Hayakawa, Masashi; Herdoiza, Gregorio; Hoferichter, Martin; Huang, Guangshun; Jansen, Karl; Jegerlehner, Fred; Kloss, Benedikt; Kubis, Bastian; Liu, Zhiqing; Marciano, William; Masjuan, Pere; Meyer, Harvey B; Mibe, Tsutomu; Nyffeler, Andreas; Pascalutsa, Vladimir; Pauk, Vladyslav; Pennington, Michael R; Peris, Santiago; Redmer, Christoph F; Sanchez-Puertas, Pablo; Shwartz, Boris; Solodov, Evgeny; Stoeckinger, Dominik; Teubner, Thomas; Unverzagt, Marc; Vanderhaeghen, Marc; Wolke, Magnus
2014-01-01
We present the mini-proceedings of the workshops Hadronic contributions to the muon anomalous magnetic moment: strategies for improvements of the accuracy of the theoretical prediction and $(g-2)_{\\mu}$: Quo vadis?, both held in Mainz from April 1$^{\\rm rst}$ to 5$^{\\rm th}$ and from April 7$^{\\rm th}$ to 10$^{\\rm th}$, 2014, respectively.
Muon anomalous magnetic moment in a $SU(4) \\otimes U(1)_N$ model without exotic electric charges
Cogollo, D
2014-01-01
We study an electroweak gauge extension of the standard model, so called 3-4-1 model, which does not contain exotic electric charges and it is anomaly free. We discuss phenomenological constraints of the model and compute all the corrections to the muon magnetic moment. Mainly, we discuss different mass regimes and their impact on this correction, deriving for the first time direct limits on the masses of the neutral fermions and charged vector bosons. Interestingly, the model could address the reported muon anomalous magnetic moment excess, however it would demands a rather low scale of symmetry breaking, far below the current electroweak constraints on the model. Thus, if this excess is confirmed in the foreseeable future by the g-2 experiment at FERMILAB, this 3-4-1 model can be decisively ruled out since the model cannot reproduce a sizeable and positive contribution to the muon anomalous magnetic moment consistent with current electroweak limits.
A Call for New Physics : The Muon Anomalous Magnetic Moment and Lepton Flavor Violation
Lindner, Manfred; Queiroz, Farinaldo S
2016-01-01
We review how the muon anomalous magnetic moment ($g-2$) and the quest for lepton flavor violation are intimately correlated. Indeed the decay $\\mu \\to e \\gamma$ is induced by the same amplitude for different choices of in- and outgoing leptons. In this work, we try to address some intriguing questions such as: Which hierarchy in the charged lepton sector one should have in order to reconcile possible signals coming simultaneously from $g-2$ and LFV? What can we learn if the $g-2$ anomaly is confirmed by the upcoming flagship experiments at FERMILAB and J-PARC, and no signal is seen in the decay $\\mu \\rightarrow e\\gamma$ in the foreseeable future? On the other hand, if the $\\mu \\rightarrow e\\gamma$ decay is seen in the upcoming years, do we need to necessarily observe a signal also in $g-2$? In this attempt, we generally study the correlation between the two phenomena in a detailed analysis of simplified models. We derive master integrals and fully analytical and exact expressions for both phenomena. We inves...
Tests of hadronic vacuum polarization fits for the muon anomalous magnetic moment
Golterman, Maarten; Peris, Santiago
2013-01-01
We construct a physically motivated model for the isospin-one non-strange vacuum polarization function Pi(Q^2) based on a spectral function given by vector-channel OPAL data from hadronic tau decays for energies below the tau mass and a successful parametrization, employing perturbation theory and a model for quark-hadron duality violations, for higher energies. Using a covariance matrix and Q^2 values from a recent lattice simulation, we then generate fake data for Pi(Q^2) and use it to test fitting methods currently employed on the lattice for extracting the hadronic vacuum polarization contribution to the muon anomalous magnetic moment. This comparison reveals a systematic error much larger than the few-percent total error sometimes claimed for such extractions in the literature. In particular, we find that errors deduced from fits using a Vector Meson Dominance ansatz are misleading, typically turning out to be much smaller than the actual discrepancy between the fit and exact model results. The use of a ...
Tests of hadronic vacuum polarization fits for the muon anomalous magnetic moment
Golterman, Maarten; Peris, Santiago
2013-01-01
Using experimental spectral data for hadronic tau decays from the OPAL experiment, supplemented by a phenomenologically successful parameterization for the high-s region not covered by the data, we construct a physically constrained model of the isospin-one vector-channel polarization function. Having such a model as a function of Euclidean momentum Q^2 allows us to explore the systematic error associated with fits to the Q^2 dependence of lattice data for the hadronic electromagnetic current polarization function which have been used in attempts to compute the leading order hadronic contribution, a_\\mu^HLO, to the muon anomalous magnetic moment. In contrast to recent claims made in the literature, we find that a final error in this quantity of the order of a few percent does not appear possible with current lattice data, given the present lack of precision in the determination of the vacuum polarization at low Q^2. We also find that fits to the vacuum polarization using fit functions based on Vector Meson Do...
New evaluation of hadronic contributions to the anomalous magnetic moment of charged leptons
International Nuclear Information System (INIS)
A re-evaluation of the lowest-order hagronic vacuum-polarization contribution to the anomalous magnetic moment of the electron, muon and tau-lepton with a higher precision in comparison with previous estimates is carried out. The latter is achieved because new data on some exclusive processes have appeared recently, more accomplished models for a description of the pion and kaon electromagnetic structure have been developed and the revised (due to a new value of the coefficient of the third power of αs) QCD formula for R=σtot (e+e-→had)/σtot (e+e-→μ+μ-) with electroweak corrections has been applied to analyze all existing data in a proper way. The final results are ae(2)had=(1.810±0.011±0.002)x10-12 aμ(2)had=(6.986±0.042±0.016)x10-8 and aτ(2)had=(3.436±0.024±0.024)x10-6. 19 refs.; 2 figs.; 3 tabs
An upper limit on the anomalous magnetic moment of the $\\tau$ lepton
Ackerstaff, K; Allison, J; Altekamp, N; Anderson, K J; Anderson, S; Arcelli, S; Asai, S; Ashby, S F; Axen, D A; Azuelos, Georges; Ball, A H; Barberio, E; Barlow, R J; Bartoldus, R; Batley, J Richard; Baumann, S; Bechtluft, J; Behnke, T; Bell, K W; Bella, G; Bentvelsen, Stanislaus Cornelius Maria; Bethke, Siegfried; Betts, S; Biebel, O; Biguzzi, A; Bird, S D; Blobel, Volker; Bloodworth, Ian J; Bobinski, M; Bock, P; Bonacorsi, D; Boutemeur, M; Braibant, S; Brigliadori, L; Brown, R M; Burckhart, Helfried J; Burgard, C; Bürgin, R; Capiluppi, P; Carnegie, R K; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Chrisman, D; Clarke, P E L; Cohen, I; Conboy, J E; Cooke, O C; Couyoumtzelis, C; Coxe, R L; Cuffiani, M; Dado, S; Dallapiccola, C; Dallavalle, G M; Davis, R; De Jong, S; del Pozo, L A; de Roeck, A; Desch, Klaus; Dienes, B; Dixit, M S; Doucet, M; Duchovni, E; Duckeck, G; Duerdoth, I P; Eatough, D; Estabrooks, P G; Etzion, E; Evans, H G; Evans, M; Fabbri, Franco Luigi; Fanfani, A; Fanti, M; Faust, A A; Feld, L; Fiedler, F; Fierro, M; Fischer, H M; Fleck, I; Folman, R; Fong, D G; Foucher, M; Fürtjes, A; Futyan, D I; Gagnon, P; Gary, J W; Gascon, J; Gascon-Shotkin, S M; Geddes, N I; Geich-Gimbel, C; Geralis, T; Giacomelli, G; Giacomelli, P; Giacomelli, R; Gibson, V; Gibson, W R; Gingrich, D M; Glenzinski, D A; Goldberg, J; Goodrick, M J; Gorn, W; Grandi, C; Gross, E; Grunhaus, Jacob; Gruwé, M; Hajdu, C; Hanson, G G; Hansroul, M; Hapke, M; Hargrove, C K; Hart, P A; Hartmann, C; Hauschild, M; Hawkes, C M; Hawkings, R; Hemingway, Richard J; Herndon, M; Herten, G; Heuer, R D; Hildreth, M D; Hill, J C; Hillier, S J; Hobson, P R; Höcker, Andreas; Homer, R James; Honma, A K; Horváth, D; Hossain, K R; Howard, R; Hüntemeyer, P; Hutchcroft, D E; Igo-Kemenes, P; Imrie, D C; Ishii, K; Jawahery, A; Jeffreys, P W; Jeremie, H; Jimack, Martin Paul; Joly, A; Jones, C R; Jones, M; Jost, U; Jovanovic, P; Junk, T R; Kanzaki, J I; Karlen, D A; Kartvelishvili, V G; Kawagoe, K; Kawamoto, T; Kayal, P I; Keeler, Richard K; Kellogg, R G; Kennedy, B W; Kirk, J; Klier, A; Kluth, S; Kobayashi, T; Kobel, M; Koetke, D S; Kokott, T P; Kolrep, M; Komamiya, S; Kowalewski, R V; Kress, T; Krieger, P; Von Krogh, J; Kyberd, P; Lafferty, G D; Lahmann, R; Lai, W P; Lanske, D; Lauber, J; Lautenschlager, S R; Lawson, I; Layter, J G; Lazic, D; Lee, A M; Lefebvre, E; Lellouch, Daniel; Letts, J; Levinson, L; List, B; Lloyd, S L; Loebinger, F K; Long, G D; Losty, Michael J; Ludwig, J; Liu, D; Macchiolo, A; MacPherson, A L; Mannelli, M; Marcellini, S; Markopoulos, C; Markus, C; Martin, A J; Martin, J P; Martínez, G; Mashimo, T; Mättig, P; McDonald, W J; McKenna, J A; McKigney, E A; McMahon, T J; McPherson, R A; Meijers, F; Menke, S; Merritt, F S; Mes, H; Meyer, J; Michelini, Aldo; Mikenberg, G; Miller, D J; Mincer, A; Mir, R; Mohr, W; Montanari, A; Mori, T; Mihara, S; Nagai, K; Nakamura, I; Neal, H A; Nellen, B; Nisius, R; O'Neale, S W; Oakham, F G; Odorici, F; Ögren, H O; Oh, A; Oldershaw, N J; Oreglia, M J; Orito, S; Pálinkás, J; Pásztor, G; Pater, J R; Patrick, G N; Patt, J; Pérez-Ochoa, R; Petzold, S; Pfeifenschneider, P; Pilcher, J E; Pinfold, J L; Plane, D E; Poffenberger, P R; Poli, B; Posthaus, A; Rembser, C; Robertson, S; Robins, S A; Rodning, N L; Roney, J M; Rooke, A M; Rossi, A M; Routenburg, P; Rozen, Y; Runge, K; Runólfsson, O; Ruppel, U; Rust, D R; Sachs, K; Saeki, T; Sahr, O; Sang, W M; Sarkisyan-Grinbaum, E; Sbarra, C; Schaile, A D; Schaile, O; Scharf, F; Scharff-Hansen, P; Schieck, J; Schleper, P; Schmitt, B; Schmitt, S; Schöning, A; Schröder, M; Schumacher, M; Schwick, C; Scott, W G; Shears, T G; Shen, B C; Shepherd-Themistocleous, C H; Sherwood, P; Sieberg, R P B; Siroli, G P; Sittler, A; Skillman, A; Skuja, A; Smith, A M; Snow, G A; Sobie, Randall J; Söldner-Rembold, S; Springer, R W; Sproston, M; Stephens, K; Steuerer, J; Stockhausen, B; Stoll, K; Strom, D; Ströhmer, R; Szymanski, P; Tafirout, R; Talbot, S D; Taras, P; Tarem, S; Teuscher, R; Thiergen, M; Thomson, M A; Von Törne, E; Torrence, E; Towers, S; Trigger, I; Trócsányi, Z L; Tsur, E; Turcot, A S; Turner-Watson, M F; Ueda, I; Utzat, P; Van Kooten, R; Vannerem, P; Verzocchi, M; Vikas, P; Vokurka, E H; Voss, H; Wäckerle, F; Wagner, A; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, N K; Wells, P S; Wermes, N; White, J S; Wilson, G W; Wilson, J A; Wyatt, T R; Yamashita, S; Yekutieli, G; Zacek, V; Zer-Zion, D
1998-01-01
Using radiative Z^0 -> \\tau^+ \\tau^- \\gamma events collected with the OPAL detector at LEP at \\sqrt{s}=M_Z during 1990-95, a direct study of the electromagnetic current at the \\tau\\gamma vertex has been performed in terms of the anomalous magnetic form factor F_2 of the \\tau lepton. The analysis is based on a data sample of 1429 e^+ e^- -> \\tau^+ \\tau^- \\gamma events which are examined for a deviation from the expectation with F_2 = 0. From the non-observation of anomalous \\tau^+ \\tau^- \\gamma production a limit of -0.068 < F_2 < 0.065 is obtained. This can also be interpreted as a limit on the electric dipole form factor F_3 as -3.8 x 10^-16 e-cm < eF_3 < 3.6 x 10^-16 e-cm. The above ranges are valid at the 95% confidence level.
Light-by-light-type corrections to the muon anomalous magnetic moment at four-loop order
Energy Technology Data Exchange (ETDEWEB)
Kurz, Alexander [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). Inst. fuer Theoretische Teilchenphysik; Liu, Tao; Steinhauser, Matthias [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). Inst. fuer Theoretische Teilchenphysik; Marquard, Peter [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Smirnov, Alexander V. [Moscow State Univ. (Russian Federation). Scientific Research Computing Center; Smirnov, Vladimir A. [Moscow State Univ. (Russian Federation). Skobeltsyn Inst. of Nuclear Physics
2015-08-15
The numerically dominant QED contributions to the anomalous magnetic moment of the muon stem from Feynman diagrams with internal electron loops. We consider such corrections and present a calculation of the four-loop light-by-light-type corrections where the external photon couples to a closed electron or muon loop. We perform an asymptotic expansion in the ratio of electron and muon mass and reduce the resulting integrals to master integrals which we evaluate using analytical and numerical methods. We confirm the results present in the literature which are based on different computational methods.
Jin, Luchang; Christ, Norman; Hayakawa, Masashi; Izubuchi, Taku; Lehner, Christoph
2015-01-01
The anomalous magnetic moment of muon, $g-2$, is a very precisely measured quantity. However, the current measurement disagrees with standard model by about 3 standard deviations. Hadronic vacuum polarization and hadronic light by light are the two types of processes that contribute most to the theoretical uncertainty. I will describe how lattice methods are well-suited to provide a first-principle's result for the hadronic light by light contribution, the various numerical strategies that are presently being used to evaluate it, our current results and the important remaining challenges which must be overcome.
A Study of Neutron Star Structure in Strong Magnetic Fields that includes Anomalous Magnetic Moments
Institute of Scientific and Technical Information of China (English)
Guang-Jun Mao; Akira Iwamoto; Zhu-Xia Li
2003-01-01
We study the effect of strong magnetic fields on the structure of neutronstar. We find that if the interior field is on the same order as the surface fieldcurrently observed, then the influences of the field on the star's mass and radius arenegligible; if the field is as large as that estimated from the scalar virial theorem,then considerable effects will be induced. The maximum mass of the star will beincreased substantially while the central density is greatly reduced. The radius ofa magnetic star can be larger by about 10% ～ 20% than a nonmagnetic star of thesame mass.
International Nuclear Information System (INIS)
For the system consisting of a neutral Dirac particle with anomalous magnetic moment, interacting with a fixed magnetic monopole, zero-energy bound states are constructed for each possible value of the total angular momentum. Results of Kazama and Yang for the charge--monopole system are used to deduce the existence of other bound states for this system, when the mass of the bound particle is nonzero. In the zero-mass case, there are no other bound states, but there are resonant states, and these are determined exactly. A noncompact, so(3,2) symmetry algebra of the zero-energy bound states is given for the finite-mass case and for the zero-mass case. In each case the infinite number of such states is associated with an irreducible Majorana representation of the algebra
Blum, Thomas; Hayakawa, Masashi; Izubuchi, Taku; Jin, Luchang; Jung, Chulwoo; Lehner, Christoph
2016-01-01
We report a lattice QCD calculation of the hadronic light-by-light contribution to the muon anomalous magnetic moment at physical pion mass. The calculation includes the connected diagrams and the leading, quark-line-disconnected diagrams. We incorporate algorithmic improvements developed in our previous work. The calculation was performed on the $48^3 \\times 96$ ensemble generated with a physical-pion-mass and a 5.5 fm spatial extent by the RBC and UKQCD collaborations using the chiral, domain wall fermion (DWF) formulation. We find $a_\\mu^{\\text{HLbL}} = 5.35 (1.35) \\times 10^{- 10}$, where the error is statistical only. The finite-volume and finite lattice-spacing errors could be quite large and are the subject of on-going research. The omitted disconnected graphs, while expected to give a correction of order 10\\%, also need to be computed.
International Nuclear Information System (INIS)
Requiring the two-Higgs-doublet model II to accommodate the 3σ deviation in the muon anomalous magnetic moment imposes specific constraints on the Higgs spectrum. We analyze the combination of all the relevant available constraints on the model parameter space. The use of constraints from b→sγ, the precision electroweak measurements of Rb, and the ρ parameter, together with exclusions from direct searches at CERN LEP, gives extremely severe restrictions on the model parameters. That is 'almost enough' to destroy the model altogether. The exclusion would be even stronger if the direct searches could be optimized to complement the other constraints, as will be discussed in detail in this work
Khalilov, V. R.
The scattering of a nonrelativistic neutral massive fermion having the anomalous magnetic moment (AMM) in an electric field of a uniformly charged long conducting thread aligned perpendicularly to the fermion motion is considered to study the so-called Aharonov-Casher (AC) effect by taking into account the particle spin. For this solution, the nonrelativistic Dirac-Pauli equation for a neutral massive fermion with AMM in (3+1) dimensions is found, which takes into account explicitly the particle spin and interaction between AMM of moving fermion and the electric field. Expressions for the scattering amplitude and the cross-section are obtained for spin-polarized massive neutral fermion scattered off the above conducting thread. We conclude that the scattering amplitude and cross-section of spin-polarized massive neutral fermions are influenced by the interaction of AMM of moving neutral fermions with the electric field as well as by the polarization of fermion beam in the initial state.
Elhandi, S; attaourti, Y; Manaut, B; Oufni, L
2010-01-01
The effect of the electron's anomalous magnetic moment on the relativistic electronic dressing for the process of electron-hydrogen atom elastic collisions is investigated. We consider a laser field with circular polarization and various electric field strengths. The Dirac-Volkov states taking into account this anomaly are used to describe the process in the first order of perturbation theory. The correlation between the terms coming from this anomaly and the electric field strength gives rise to new results, namely the strong dependence of the spinor part of the differential cross section (DCS) with respect to these terms. A detailed study has been devoted to the non relativistic regime as well as the moderate relativistic regime. Some aspects of this dependence as well as the dynamical behavior of the DCS in the relativistic regime have been addressed.
Porter, Frank C
2013-01-01
The BaBar collaboration has an extensive program of studying hadronic cross sections in low-energy e+e- collisions, accessible via initial-state radiation. Our measurements allow significant improvements in the precision of the predicted value of the muon anomalous magnetic moment. These improvements are necessary for illuminating the current ~3.6 sigma difference between the predicted and the experimental values. We have published results on a number of processes with two to six hadrons in the final state. We report here the results of recent studies with final states that constitute the main contribution to the hadronic cross section in the energy region between 1 and 3 GeV, as e+e- to K+K-, pi+pi-, and e+e- to 4 hadrons.
Baryshevsky, V G
2016-01-01
The degree of depolarization of neutral particles in crystals can reach tens of percents over the crystal length of several centimeters, which can be the basis for possible experimental application of the depolarization effect for measuring anomalous magnetic moments of short-lived neutral hyperons.
Ferrer, E J; Paret, D Manreza; Martinez, A Perez; Sanchez, A
2015-01-01
We investigate the effects of the anomalous magnetic moment (AMM) in the equation of state (EoS) of a system of charged fermions at finite density in the presence of a magnetic field. In the region of strong magnetic fields (eB>m^2) the AMM is found from the one-loop fermion self-energy. In contrast to the weak-field AMM found by Schwinger, in the strong magnetic field region the AMM depends on the Landau level and decreases with it. The effects of the AMM in the EoS of a dense medium are investigated at strong and weak fields using the appropriate AMM expression for each case. In contrast with what has been reported in other works, we find that the AMM of charged fermions makes no significant contribution to the EoS at any field value.
A to Z of the muon anomalous magnetic moment in the MSSM with Pati-Salam at the GUT scale
Belyaev, Alexander S.; Camargo-Molina, José E.; King, Steve F.; Miller, David J.; Morais, António P.; Schaefers, Patrick B.
2016-06-01
We analyse the low energy predictions of the minimal supersymmetric standard model (MSSM) arising from a GUT scale Pati-Salam gauge group further constrained by an A 4 × Z 5 family symmetry, resulting in four soft scalar masses at the GUT scale: one left-handed soft mass m 0 and three right-handed soft masses m 1 , m 2 , m 3, one for each generation. We demonstrate that this model, which was initially developed to describe the neutrino sector, can explain collider and non-collider measurements such as the dark matter relic density, the Higgs boson mass and, in particular, the anomalous magnetic moment of the muon ( g - 2) μ . Since about two decades, ( g - 2) μ suffers a puzzling about 3 σ excessoftheexperimentallymeasuredvalueoverthetheoreticalprediction,whichour model is able to fully resolve. As the consequence of this resolution, our model predicts specific regions of the parameter space with the specific properties including light smuons and neutralinos, which could also potentially explain di-lepton excesses observed by CMS and ATLAS.
A to Z of the Muon Anomalous Magnetic Moment in the MSSM with Pati-Salam at the GUT scale
Belyaev, Alexander S; King, Steve F; Miller, David J; Morais, António P; Schaefers, Patrick B
2016-01-01
We analyse the low energy predictions of the minimal supersymmetric standard model (MSSM) arising from a GUT scale Pati-Salam gauge group further constrained by an $A_4 \\times Z_5$ family symmetry, resulting in four soft scalar masses at the GUT scale: one left-handed soft mass $m_0$ and three right-handed soft masses $m_1,m_2,m_3$, one for each generation. We demonstrate that this model, which was initially developed to describe the neutrino sector, can explain collider and non-collider measurements such as the dark matter relic density, the Higgs boson mass and, in particular, the anomalous magnetic moment of the muon $(g-2)_\\mu$. Since about two decades, $(g-2)_\\mu$ suffers a puzzling about 3$\\,\\sigma$ excess of the experimentally measured value over the theoretical prediction, which our model is able to fully resolve. As the consequence of this resolution, our model predicts specific regions of the parameter space with the specific properties including light smuons and neutralinos, which could also potent...
Anomalous magnetic moments in Fe-Pt and Fe-Pd Invar alloys under high pressure
Matsushita, M; Endo, S; Ishizuka, M; Kindo, K; Ono, F
2002-01-01
Magnetization measurements have been carried out for disordered Fe sub 7 sub 2 Pt sub 2 sub 8 , Fe sub 6 sub 6 Pd sub 3 sub 4 , and Fe sub 6 sub 8 Pd sub 3 sub 2 Invar alloys under high pressure using a technique combining a pressure-clamp-type Drickamer cell and a pulse magnet. In Fe sub 7 sub 2 Pt sub 2 sub 8 at room temperature, the magnetization decreased rapidly with increasing pressure up to 2.5 GPa, but above 2.5 GPa the rate of decrease became small and remained at a small value up to 5.6 GPa. In Fe-Pd Invar alloys at room temperature, the magnetization decreased linearly with increasing pressure. But, at 4.2 K, the change of magnetization with pressure was small in Fe sub 6 sub 6 Pd sub 3 sub 4 , which means that Fe sub 6 sub 6 Pd sub 3 sub 4 behaves as a strong ferromagnet.
Energy Technology Data Exchange (ETDEWEB)
Carey, R.M.; Lynch, K.R.; Miller, J.P.; Roberts, B.L.; Morse, W.M.; Semertzides, Y.K.; Druzhinin, V.P.; Khazin, B.I.; Koop, I.A.; Logashenko, I.; Redin, S.I.; /Boston U. /Brookhaven /Novosibirsk, IYF /Cornell U., CIHEP /Fermilab /Frascati /Illinois U., Urbana /James Madison U. /Groningen, KVI /KEK, Tsukuba /Kentucky U.
2009-02-01
We propose to measure the muon anomalous magnetic moment, a{sub {mu}}, to 0.14 ppm-a fourfold improvement over the 0.54 ppm precision obtained in the BNL experiment E821. The muon anomaly is a fundamental quantity and its precise determination will have lasting value. The current measurement was statistics limited, suggesting that greater precision can be obtained in a higher-rate, next-generation experiment. We outline a plan to use the unique FNAL complex of proton accelerators and rings to produce high-intensity bunches of muons, which will be directed into the relocated BNL muon storage ring. The physics goal of our experiment is a precision on the muon anomaly of 16 x 10{sup -11}, which will require 21 times the statistics of the BNL measurement, as well a factor of 3 reduction in the overall systematic error. Our goal is well matched to anticipated advances in the worldwide effort to determine the standard model (SM) value of the anomaly. The present comparison, {Delta}a{sub {mu}} (Expt: -SM) = (295 {+-} 81) x 10{sup -11}, is already suggestive of possible new physics contributions to the muon anomaly. Assuming that the current theory error of 51 x 10{sup -11} is reduced to 30 x 10{sup -11} on the time scale of the completion of our experiment, a future {Delta}a{sub {mu}} comparison would have a combined uncertainty of {approx} 34 x 10{sup -11}, which will be a sensitive and complementary benchmark for proposed standard model extensions. The experimental data will also be used to improve the muon EDM limit by up to a factor of 100 and make a higher-precision test of Lorentz and CPT violation. We describe in this Proposal why the FNAL complex provides a uniquely ideal facility for a next-generation (g-2) experiment. The experiment is compatible with the fixed-target neutrino program; indeed, it requires only the unused Booster batch cycles and can acquire the desired statistics in less than two years of running. The proton beam preparations are largely aligned
Burger, Florian; Hotzel, Grit; Jansen, Karl; Petschlies, Marcus; Renner, Dru B
2013-01-01
We present results for the leading order QCD correction to the anomalous magnetic moment of the muon including the first two generations of quarks as dynamical degrees of freedom. Several light quark masses are examined in order to yield a controlled extrapolation to the physical pion mass. We analyse ensembles for three different lattice spacings and several volumes in order to investigate lattice artefacts and finite-size effects, respectively. We also provide preliminary results for this quantity for two flavours of mass-degenerate quarks at the physical value of the pion mass.
Energy Technology Data Exchange (ETDEWEB)
Burger, Florian; Hotzel, Grit [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Feng, Xu [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki (Japan); Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Petschlies, Marcus [The Cyprus Institute, Nicosia (Cyprus); Renner, Dru B. [Jefferson Lab, Newport News, VA (United States)
2013-12-15
We present results for the leading order QCD correction to the anomalous magnetic moment of the muon including the first two generations of quarks as dynamical degrees of freedom. Several light quark masses are examined in order to yield a controlled extrapolation to the physical pion mass. We analyse ensembles for three different lattice spacings and several volumes in order to investigate lattice artefacts and finite-size effects, respectively. We also provide preliminary results for this quantity for two flavours of mass-degenerate quarks at the physical value of the pion mass.
Energy Technology Data Exchange (ETDEWEB)
Burger, Florian [Humboldt U. Berlin; Feng, Xu [KEK; Hotzel, Grit [Humboldt U. Berlin; Jansen, Karl [DESY; Petschlies, Marcus [The Cyprus Institute; Renner, Dru B. [JLAB
2013-11-01
We present results for the leading order QCD correction to the anomalous magnetic moment of the muon including the first two generations of quarks as dynamical degrees of freedom. Several light quark masses are examined in order to yield a controlled extrapolation to the physical pion mass. We analyse ensembles for three different lattice spacings and several volumes in order to investigate lattice artefacts and finite-size effects, respectively. We also provide preliminary results for this quantity for two flavours of mass-degenerate quarks at the physical value of the pion mass.
Rosado, A
2003-01-01
We discuss the production of W-+ bosons in deep inelastic processes (anti-nu)nu + nucleon --> l+- + W-+ + X, in the context of an electroweak model in which the vector boson self interactions may be different from those prescribed by the electroweak standard model. We present results which show the strong dependence of the cross section on the anomalous magnetic dipole moment kappa of the W+-. We show that even small deviations from the standard model value of kappa (kappa=1) could imply observable deviations in the cross section rates of W-+ production through the collision of an ultrahigh energy (anti)neutrino on a target nucleon.
Volkov, S. A.
2016-06-01
A new subtractive procedure for canceling ultraviolet and infrared divergences in the Feynman integrals described here is developed for calculating QED corrections to the electron anomalous magnetic moment. The procedure formulated in the form of a forest expression with linear operators applied to Feynman amplitudes of UV-diverging subgraphs makes it possible to represent the contribution of each Feynman graph containing only electron and photon propagators in the form of a converging integral with respect to Feynman parameters. The application of the developed method for numerical calculation of two- and threeloop contributions is described.
Ortenzi, L.; Gretarsson, H.; Kasahara, S.; Matsuda, Y.; Shibauchi, T.; Finkelstein, K. D.; Wu, W.; Julian, S. R.; Kim, Young-June; Mazin, I. I.; Boeri, L.
2015-01-01
We report a combination of Fe K β x-ray emission spectroscopy and density functional reduced Stoner theory calculations to investigate the correlation between structural and magnetic degrees of freedom in CaFe2(As1-xPx) 2 . The puzzling temperature behavior of the local moment found in rare earth-doped CaFe2As2 [H. Gretarsson et al., Phys. Rev. Lett. 110, 047003 (2013)] is also observed in CaFe2(As1-xPx) 2 . We explain this phenomenon based on first-principles calculations with scaled magnetic interaction. One scaling parameter is sufficient to describe quantitatively the magnetic moments in both CaFe2(As1-xPx) 2 (x =0.055 ) and Ca0.78La0.22Fe2As2 at all temperatures. The anomalous growth of the local moments with increasing temperature can be understood from the observed large thermal expansion of the c -axis lattice parameter combined with strong magnetoelastic coupling. These effects originate from the strong tendency to form As-As dimers across the Ca layer in the CaFe2As2 family of materials. Our results emphasize the dual local-itinerant character of magnetism in Fe pnictides.
Chakraborty, Bipasha; Donald, Gordon; Dowdall, Rachel; de Oliveira, Pedro Gonçalves; Koponen, Jonna; Lepage, G Peter; Teubner, T
2014-01-01
We describe a new technique (presented in arXiv:1403.1778) to determine the contribution to the anomalous magnetic moment (g-2) of the muon coming from the hadronic vacuum polarisation using lattice QCD. Our method uses Pad\\'{e} approximants to reconstruct the Adler function from its derivatives at $q^2=0$. These are obtained simply and accurately from time-moments of the vector current-current correlator at zero spatial momentum. We test the method using strange quark correlators calculated on MILC Collaboration's $n_f$ = 2+1+1 HISQ ensembles at multiple values of the lattice spacing, multiple volumes and multiple light sea quark masses (including physical pion mass configurations).
Gonzalez-Martin, Gustavo R; Gonzalez, Javier G
2004-01-01
The magnetic moment of the proton is calculated using a geometric unified theory. The geometry determines a generalized Pauli equation showing anomalous terms due to the triplet proton structure. The theoretical result gives a bare anomalous Lande gyromagnetic g-factor close to the experimental value. The necessary radiative corrections should be included in the actual theoretical dressed value. The first order correction raises the value to 2(2.7796). Similarly we obtain for the neutron gyromagnetic g-factor the value 2(1.9267).
Gutiérrez-Rodríguez, A
2000-01-01
We discuss the production of charged bosons in deep inelastic e-p- scattering, in the context of an electroweak model, in which the vector boson self interactions may be different from those prescribed by the electroweak standard model. We present results which show the strong dependence of the cross section on the anomalous magnetic dipole moment kappa of the W/sup +or-/. We show that even small deviations from the standard model value of kappa ( kappa =1) implies an observable deviation in the W/sup +or-/-production rates at CERN LEP/LHC energies. We also show that for the analysis of the charged boson production via e/sup -/p collisions at LEP/LHC energies will be very important to include the contribution from heavy boson exchange diagrams to the cross section rates. (25 refs).
Energy Technology Data Exchange (ETDEWEB)
Porter, Frank C. [Caltech, Pasadena, CA (United States). Physics Dept.
2015-04-29
The BABAR collaboration has an extensive program of studying hadronic cross sections in low-energy e^{+}e^{-} collisions, accessible via initial-state radiation. Our measurements allow significant improvements in the precision of the predicted value of the muon anomalous magnetic moment. These improvements are necessary for illuminating the current 3.6 sigma difference between the predicted and the experimental values. We have published results on a number of processes with two to six hadrons in the final state. We report here the results of recent studies with final states that constitute the main contribution to the hadronic cross section in the energy region between 1 and 3 GeV, as e^{+}e^{-} → K^{+}K^{-}, π^{+}π^{-}, and e^{+}e^{-} → 4 hadrons
New method of determining the magnetic moment of the electron
Energy Technology Data Exchange (ETDEWEB)
Sokolov, A.A.; Pavlenko, Y.G.
1977-11-01
The Pauli equation is solved for electrons moving in crossed magnetic and electrostatic fields of two different configurations. It is shown that the frequency shift of radiative dipole transitions is related to the anomalous magnetic moment. This fact can be used to determine experimentally the anomalous magnetic moment of the electron.
Gray, F E
2003-01-01
The anomalous magnetic moment of the positive muon has been measured to a precision of 0.7 parts per million in an experiment at Brookhaven National Laboratory. The standard model prediction for this quantity can be calculated with a similar uncertainty, although there are currently inconsistent results for one crucial part of this evaluation. Comparison of the theoretical and experimental values tests the standard model and probes for physics beyond it, including supersymmetry, for which a large signal is expected from many models. This thesis describes the principle of the experiment and the status of the theoretical evaluations. It concentrates on the details of an energy-binned method of determining the anomalous precession frequency from the recorded data. The result that is obtained, after combination with previous measurements, is aexp;avgm=11659203 8×10- 10, to be compared with the present standard model predictions aSM;e+e- m =11659168.87.7×10 -10and aSM;tm=11659193.2 6.8&...
International Nuclear Information System (INIS)
I would like to discuss the problem of a neutrino magnetic moment which is of interest since it deals with the probable time anticorrelation of the solar v flux with the Sun magnetic activity. (author). 19 refs, 2 figs, 1 tab
Search for anomalous weak dipole moments of the $\\tau$ lepton
Heister, A; Barate, R; De Bonis, I; Décamp, D; Goy, C; Lees, J P; Merle, E; Minard, M N; Pietrzyk, B; Bravo, S; Casado, M P; Chmeissani, M; Crespo, J M; Fernández, E; Fernández-Bosman, M; Garrido, L; Martínez, M; Pacheco, A; Ruiz, H; Colaleo, A; Creanza, D; De Palma, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Nuzzo, S; Ranieri, A; Raso, G; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Tricomi, A; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Abbaneo, D; Azzurri, P; Buchmüller, O L; Cattaneo, M; Cerutti, F; Clerbaux, B; Drevermann, H; Forty, R W; Frank, M; Gianotti, F; Hansen, J B; Harvey, J; Hutchcroft, D E; Janot, P; Jost, B; Kado, M; Mato, P; Moutoussi, A; Ranjard, F; Rolandi, Luigi; Schlatter, W D; Schneider, O; Sguazzoni, G; Tejessy, W; Teubert, F; Valassi, Andrea; Videau, I; Ward, J; Badaud, F; Falvard, A; Gay, P; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Kyriakis, A; Markou, C; Simopoulou, Errietta; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Rougé, A; Rumpf, M; Swynghedauw, M; Verderi, M; Videau, H L; Ciulli, V; Focardi, E; Parrini, G; Antonelli, A; Antonelli, M; Bencivenni, G; Bossi, F; Capon, G; Chiarella, V; Laurelli, P; Mannocchi, G; Murtas, G P; Passalacqua, L; Pepé-Altarelli, M; Lynch, J G; Negus, P; O'Shea, V; Raine, C; Thompson, A S; Wasserbaech, S R; Cavanaugh, R J; Geweniger, C; Hanke, P; Hepp, V; Kluge, E E; Putzer, A; Stenzel, H; Tittel, K; Wunsch, M; Beuselinck, R; Binnie, David M; Cameron, W; Dornan, P J; Girone, M; Marinelli, N; Sedgbeer, J K; Thompson, J C; Ghete, V M; Girtler, P; Kneringer, E; Kuhn, D; Rudolph, G; Bouhova-Thacker, E; Bowdery, C K; Finch, A J; Foster, F; Hughes, G; Jones, R W L; Pearson, M R; Robertson, N A; Jakobs, K; Kleinknecht, K; Renk, B; Sander, H G; Wachsmuth, H W; Zeitnitz, C; Bonissent, A; Coyle, P; Leroy, O; Payre, P; Rousseau, D; Talby, M; Ragusa, F; David, A; Dietl, H; Ganis, G; Hüttmann, K; Lütjens, G; Männer, W; Moser, H G; Settles, Ronald; Wolf, G; Boucrot, J; Callot, O; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Jacholkowska, A; Lefrançois, J; Veillet, J J; Yuan, C; Bagliesi, G; Boccali, T; Foà, L; Giammanco, A; Giassi, A; Ligabue, F; Messineo, A; Palla, Fabrizio; Sanguinetti, G; Sciabà, A; Tenchini, Roberto; Venturi, A; Verdini, P G; Blair, G A; Cowan, G; Green, M G; Medcalf, T; Misiejuk, A; Strong, J A; Teixeira-Dias, P; Clifft, R W; Edgecock, T R; Norton, P R; Tomalin, I R; Bloch-Devaux, B; Colas, P; Lançon, E; Lemaire, M C; Locci, E; Pérez, P; Rander, J; Schuller, J P; Vallage, B; Konstantinidis, N P; Litke, A M; Taylor, G; Booth, C N; Cartwright, S L; Combley, F; Lehto, M H; Thompson, L F; Böhrer, A; Brandt, S; Grupen, Claus; Ngac, A; Prange, G; Giannini, G; Rothberg, J E; Armstrong, S R; Berkelman, K; Cranmer, K; Ferguson, D P S; Gao, Y; Gonzáles, S; Hayes, O J; Hu, H; Jin, S; Kile, J; McNamara, P A; Nielsen, J; Pan, Y B; Von Wimmersperg-Töller, J H; Wiedenmann, W; Wu, J; Wu Sau Lan; Wu, X; Zobernig, G; Dissertori, G
2003-01-01
The anomalous weak dipole moments of the $\\tau$ lepton are measured in a data sample collected by ALEPH from 1990 to 1995 corresponding to an integrated luminosity of 155~pb$^{-1}$. Tau leptons produced in the reaction $e^+ e^- \\rightarrow \\tau^+ \\tau^-$ at energies close to the ${\\rm Z}$ mass are studied using their semileptonic decays to $\\pi$, $\\rho$, $a_1 \\rightarrow \\pi 2\\pi^0$ or $a_1 \\rightarrow 3 \\pi$. The real and imaginary components of both the anomalous weak magnetic dipole moment and the CP-violating anomalous weak electric dipole moment, $ {\\rm Re}\\,\\mu_{\\tau}$, ${\\rm Im}\\,\\mu_{\\tau}$, ${\\rm Re}\\,d_{\\tau}$ and ${\\rm Im}\\,d_{\\tau}$, are measured simultaneously by means of a likelihood fit built from the full differential cross section. No evidence of new physics is found. The following bounds are obtained (95\\% CL): $|{\\rm Re}\\, \\mu_{\\tau} | < 1.14 \\times 10^{-3}$, $|{\\rm Im}\\, \\mu_{\\tau} | < 2.65 \\times 10^{-3}$, $|{\\rm Re}\\, d_{\\tau} | < 0.91 \\times 10^{-3}$, and $|{\\rm Im}\\, d_{\\tau} ...
Aoyama, T; Kinoshita, T; Nio, M
2011-01-01
This paper reports the tenth-order contributions to the g-2 of the electron a_e and those of the muon a_mu from the gauge-invariant Set II(c), which consists of 36 Feynman diagrams, and Set II(d), which consists of 180 Feynman diagrams. Both sets are obtained by insertion of sixth-order vacuum-polarization diagrams in the fourth-order anomalous magnetic moment. The mass-independent contributions from Set II(c) and Set II(d) are -0.116 489 (32)(alpha/pi)^5 and -0.243 00 (29)(alpha/pi)^5, respectively. The leading contributions to a_mu, which involve electron loops only, are -3.888 27 (90)(alpha/pi)^5 and 0.4972 (65)(alpha/pi)^5 for Set II(c) and Set II(d), respectively. The total contributions of the electron, muon, and tau-lepton loops to a_e are -0.116 874 (32) (alpha/pi)^5 for Set II(c) and -0.243 10 (29) (alpha/pi)^5 for Set II(d). The contributions of electron, muon, and tau-lepton loops to a_mu are -5.5594 (11) (alpha/pi)^5 for Set II(c) and 0.2465 (65) (alpha/pi)^5 for Set II(d).
Biswas, Anirban; Khan, Sarif
2016-01-01
The observation of neutrino masses, mixing and the existence of dark matter are amongst the most important signatures of physics beyond the Standard Model (SM). In this paper, we propose to extend the SM by a local $L_\\mu - L_\\tau$ gauge symmetry, two additional complex scalars and three right-handed neutrinos. The $L_\\mu - L_\\tau$ gauge symmetry is broken spontaneously when one of the scalars acquires a vacuum expectation value. The $L_\\mu - L_\\tau$ gauge symmetry is known to be anomaly free and can explain the beyond SM measurement of the anomalous muon $({\\rm g-2})$ through additional contribution arising from the extra $Z_{\\mu\\tau}$ mediated diagram. Small neutrino masses are explained naturally through the Type-I seesaw mechanism, while the mixing angles are predicted to be in their observed ranges due to the broken $L_\\mu-L_\\tau$ symmetry. The second complex scalar is shown to be stable and becomes the dark matter candidate in our model. We show that while the $Z_{\\mu\\tau}$ portal is ineffective for the...
International Nuclear Information System (INIS)
We propose to measure the muon anomalous magnetic moment, aμ, to 0.14 ppm-a fourfold improvement over the 0.54 ppm precision obtained in the BNL experiment E821. The muon anomaly is a fundamental quantity and its precise determination will have lasting value. The current measurement was statistics limited, suggesting that greater precision can be obtained in a higher-rate, next-generation experiment. We outline a plan to use the unique FNAL complex of proton accelerators and rings to produce high-intensity bunches of muons, which will be directed into the relocated BNL muon storage ring. The physics goal of our experiment is a precision on the muon anomaly of 16 x 10-11, which will require 21 times the statistics of the BNL measurement, as well a factor of 3 reduction in the overall systematic error. Our goal is well matched to anticipated advances in the worldwide effort to determine the standard model (SM) value of the anomaly. The present comparison, Δaμ (Expt: -SM) = (295 ± 81) x 10-11, is already suggestive of possible new physics contributions to the muon anomaly. Assuming that the current theory error of 51 x 10-11 is reduced to 30 x 10-11 on the time scale of the completion of our experiment, a future Δaμ comparison would have a combined uncertainty of ∼ 34 x 10-11, which will be a sensitive and complementary benchmark for proposed standard model extensions. The experimental data will also be used to improve the muon EDM limit by up to a factor of 100 and make a higher-precision test of Lorentz and CPT violation. We describe in this Proposal why the FNAL complex provides a uniquely ideal facility for a next-generation (g-2) experiment. The experiment is compatible with the fixed-target neutrino program; indeed, it requires only the unused Booster batch cycles and can acquire the desired statistics in less than two years of running. The proton beam preparations are largely aligned with the new Mu2e experimental requirements. The (g-2) experiment
Strange magnetic moments of octet baryons under SU(3) breaking
Institute of Scientific and Technical Information of China (English)
CAO Lu; WANG Biao; CHEN Hong
2012-01-01
Magnetic moments of octet baryons are parameterized to all orders of the flavor SU(3) breaking with the irreducible tensor technique in order to extract the contribution of each flavor quark to the magnetic moments of the octet baryons.The not-yet measured magnetic moment of Σ0 is predicted to be 0.649 μN.Our parameterized forms for the magnetic moments are explicitly flavor-dependent,and hence each flavor component of the magnetic moments can be evaluated directly via the flavor projection operator.It is fouud that the strange magnetic moment of the nucleon is suppressed due to the small isoscalar anomalous magnetic moment of the nucleon.In particular,the strange magnetic form factor of the nucleon turns out to be positive,(G(s)N) (0) =0.428 μN,which is consistent with recent data.
Measurement of the electric dipole moment and magnetic moment anomaly of the muon
Onderwater, CJG
2005-01-01
The experimental precision of the anomalous magnetic moment of the muon has been improved to 0.5 part-per-million by the Brookhaven E821 experiment, similar to the theoretical uncertainty. In the same experiment, a new limit on the electric dipole moment of 2.8 x 10(-19) e-cm (95% CL) was set. The e
2002-01-01
Experiment IS358 uses the intense and pure beams of copper isotopes provided by the ISOLDE RILIS (resonance ionization laser ion source). The isotopes are implanted and oriented in the low temperature nuclear orientation set-up NICOLE. Magnetic moments are measured by $\\beta$-NMR. Copper (Z=29), with a single proton above the proton-magic nickel isotopes provides an ideal testground for precise shell model calculations of magnetic moments and their experimental verification. In the course of our experiments we already determined the magnetic moments of $^{67}$Ni, $^{67}$Cu, $^{68g}$Cu, $^{69}$Cu and $^{71}$Cu which provide important information on the magicity of the N=40 subshell closure. In 2001 we plan to conclude our systematic investigations by measuring the magnetic moment of the neutron-deficient isotope $^{59}$Cu. This will pave the way for a subsequent study of the magnetic moment of $^{57}$Cu with a complementary method.
Quantization of Spinning Particle with Anomalous Magnetic Momentum
Gitman, D. M.; Saa, A. V.
1992-01-01
A generalization of the pseudoclassical action of a spinning particle in the presence of an anomalous magnetic moment is given. The leading considerations, to write the action, are gotten from the path integral representation for the causal Green's function of the generalized (by Pauli) Dirac equation for the particle with anomalous magnetic momentum in an external electromagnetic field. The action can be written in reparametrization and supergauge invariant form. Both operator (Dirac) and pa...
Anomalous center of mass shift gravitational dipole moment
Jeong, E J
1996-01-01
The anomalous, energy dependent shift of the center of mass of an idealized, perfectly rigid, uniformly rotating hemispherical shell which is caused by the relativistic mass increase effect is investigated in detail. It is shown that a classical object on impact which has the harmonic binding force between the adjacent constituent particles has the similar effect of the energy dependent, anomalous shift of the center of mass. From these observations, the general mode of the linear acceleration is suggested to be caused by the anomalous center of mass shift whether it's due to classical or relativistic origin. The effect of the energy dependent center of mass shift perpendicular to the plane of rotation of a rotating hemisphere appears as the non zero gravitational dipole moment in general relativity. Controlled experiment for the measurement of the gravitational dipole field and its possible links to the cylindrical type line formation of a worm hole in the extreme case are suggested. The jets from the black ...
Lagrangian magnetic moment from polarization
Braghin, Fabio L
2016-01-01
An effective Lagrangian term for the electron magnetic moment, and more generally electromagnetic form factors, is calculated by considering the background field method. Two Fierz transformations are performed for a one-photon exchange interaction, and the ambiguity in doing such transformations is exploited. The resulting effective interaction may exhibit an approximated rotational chiral symmetry either for the scalar-pseudoscalar currents interaction or for the vector-axial currents interaction. The leading terms in the expansion of the fermion determinant yield the leading QED effective action with the complete one loop electromagnetic form factors. A model is proposed to produce the tree level magnetic moment term.
Anomalous center of mass shift: gravitational dipole moment.
Jeong, Eue Jin
1997-02-01
The anomalous, energy dependent shift of the center of mass of an idealized, perfectly rigid, uniformly rotating hemispherical shell which is caused by the relativistic mass increase effect is investigated in detail. It is shown that a classical object on impact which has the harmonic binding force between the adjacent constituent particles has the similar effect of the energy dependent, anomalous shift of the center of mass. From these observations, the general mode of the linear acceleration is suggested to be caused by the anomalous center of mass shift whether it's due to classical or relativistic origin. The effect of the energy dependent center of mass shift perpendicular to the plane of rotation of a rotating hemisphere appears as the non zero gravitational dipole moment in general relativity. Controlled experiment for the measurement of the gravitational dipole field and its possible links to the cylindrical type line formation of a worm hole in the extreme case are suggested. The jets from the black hole accretion disc and the observed anomalous red shift from far away galaxies are considered to be the consequences of the two different aspects of the dipole gravity.
Updating neutrino magnetic moment constraints
Canas, B C; Parada, A; Tortola, M; Valle, J W F
2015-01-01
In this paper we provide an updated analysis of the neutrino magnetic moments (NMMs), discussing both the constraints on the magnitudes of the three transition moments Lambda_i as well as the role of the CP violating phases present both in the mixing matrix and in the NMM matrix. The scattering of solar neutrinos off electrons in Borexino provides the most stringent restrictions, due to its robust statistics and the low energies observed, below 1 MeV. Our new limit on the effective neutrino magnetic moment which follows from the most recent Borexino data is 3.1 x 10^-11 mu_B at 90% C.L. This corresponds to the individual transition magnetic moment constraints: |Lambda_1| < 5.6 x10^-11 mu_B, |Lambda_2| < 4.0 x 10^-11 mu_B, and |Lambda_3| < 3.1 x 10^-11 mu_B (90% C.L.), irrespective of any complex phase. Indeed, the incoherent admixture of neutrino mass eigenstates present in the solar flux makes Borexino insensitive to the Majorana phases present in the NMM matrix. For this reason we also provide a gl...
Updating neutrino magnetic moment constraints
Directory of Open Access Journals (Sweden)
B.C. Cañas
2016-02-01
Full Text Available In this paper we provide an updated analysis of the neutrino magnetic moments (NMMs, discussing both the constraints on the magnitudes of the three transition moments Λi and the role of the CP violating phases present both in the mixing matrix and in the NMM matrix. The scattering of solar neutrinos off electrons in Borexino provides the most stringent restrictions, due to its robust statistics and the low energies observed, below 1 MeV. Our new limit on the effective neutrino magnetic moment which follows from the most recent Borexino data is 3.1×10−11μB at 90% C.L. This corresponds to the individual transition magnetic moment constraints: |Λ1|≤5.6×10−11μB, |Λ2|≤4.0×10−11μB, and |Λ3|≤3.1×10−11μB (90% C.L., irrespective of any complex phase. Indeed, the incoherent admixture of neutrino mass eigenstates present in the solar flux makes Borexino insensitive to the Majorana phases present in the NMM matrix. For this reason we also provide a global analysis including the case of reactor and accelerator neutrino sources, presenting the resulting constraints for different values of the relevant CP phases. Improved reactor and accelerator neutrino experiments will be needed in order to underpin the full profile of the neutrino electromagnetic properties.
Magnetic moment and electric dipole moment of the τ-lepton
International Nuclear Information System (INIS)
Limits on the anomalous magnetic moment and the electric dipole moment of the τ lepton are calculated through the reaction e+e- → τ+τ- γ at the Z1-pole and in the framework of a left-right symmetric model. The results are based on the recent data reported by the L3 Collaboration at CERN LEP. Due to the stringent limit of the model mixing angle φ, the effect of this angle on the dipole moments is quite small
New Experiments to Measure the Muon Anomalous Gyromagnetic Moment
Eads, M
2015-01-01
The magnetic moment is a fundamental property of particles. The measurement of these magnetic moments and the comparison with the values predicted by the standard model of particle physics is a way to test our understanding of the fundamental building blocks of our world. In some cases, such as for the electron, this comparison has resulted in confirmation of the standard model with incredible precision. In contrast, the magnetic moment of the muon has shown a long-standing disagreement in the measured and the predicted value. There is currently a tantalizing three-standard-deviation difference between the current best measurement (with a precision of 0.54 ppm) and the state-of-the-art standard model prediction. This represents one of the very few experimental hints for physics beyond the standard model. There are currently two major experimental efforts underway to improve the precision of the muon magnetic moment measurement. The first is an evolution of the E-821 experiment, originally located at Brookhave...
Neutrino magnetic moment and the solar neutrino problem
International Nuclear Information System (INIS)
For a relativistic particle of mass m, energy E and anomalous magnetic moment μ, the spin-flip angle in a magnetic field B after a length L is φ=(2μBL)/hc((mc2)/E) in ultrarelativistic limit. Contrary to recent assertions, a magnetic moment of μ=10-10μO for the neutrino cannot solve the solar neutrino puzzle by spin-flip in a simple way. The reflection coefficient and other possible effects are also discussed. (author). 11 refs
Bounds on the Tau Magnetic Moments Standard Model and Beyond
González-Sprinberg, G A; Vidal, J; Gonzalez-Sprinberg, Gabriel A.; Santamaria, Arcadi; Vidal, Jorge
2001-01-01
We obtain new bounds for the magnetic dipole moments of the tau lepton. These limits on the magnetic couplings of the tau to the electroweak gauge bosons (gamma, W, Z) are set in a model independent way using the most general effective Lagrangian with the SU(2)_L x U(1)_Y symmetry. Comparison with data from the most precise experiments at high energies shows that the present limits are more stringent than the previous published ones. For the anomalous magnetic moment the bounds are, for the first time, within one order of magnitude of the standard model prediction.
Anomalous magnetic moment at Ba in Au
Bhati, A. K.; Kaur, J.; Bansal, N.; Negi, D.; Kumar, R.; Bhowmik, R. K.; Kumar, V.; Dey, C. C.
2015-04-01
The Time differential perturbed angular distribution (TDPAD) technique is employed to measure the local susceptibility at the recoil implanted Ba ions in Au following the nuclear reaction 120Sn(12C, 3nγ)129Ba. We have observed first time the local paramagnetic susceptibility of 5.26(18) at Ba ions comparable to 4f-ions in any non-ferromagnetic metal at room temperature which seems to be related to the electronic s-d and s-f transfer at positive lattice pressure.
HELMHOLTZ COILS FOR MEASURING MAGNETIC MOMENTS
Directory of Open Access Journals (Sweden)
P. N. Dobrodeyev
2013-01-01
Full Text Available The optimal configuration of the double Helmholtz coils for measuring of the magnetic dipole moments was defined. It was determined that measuring coils should have round shape and compensative coils – the square one. Analytically confirmed the feasibility of the proposed configuration of these coils as primary transmitters of magnetic dipole moments.
Magnetic moments in graphene with vacancies.
Chen, Jing-Jing; Wu, Han-Chun; Yu, Da-Peng; Liao, Zhi-Min
2014-08-01
Vacancies can induce local magnetic moments in graphene, paving the way to make magnetic functional graphene. Due to the interaction between magnetic moments and conduction carriers, the magnetotransport properties of graphene can be modulated. Here, the effects of vacancy induced magnetic moments on the electrical properties of graphene are studied via magnetotransport measurements and spin-polarized density functional theory calculations. We show by quantum Hall measurements that a sharp resonant Vπ state is introduced in the midgap region of graphene with vacancies, resulting in the local magnetic moment. The coupling between the localized Vπ state and the itinerant carrier is tuned by varying the carrier concentration, temperature, magnetic field, and vacancy density, which results in a transition between hopping transport and the Kondo effect and a transition between giant negative magnetoresistance (MR) and positive MR. This modulated magnetotransport is valuable for graphene based spintronic devices.
Quantized Anomalous Hall Effect in Magnetic Topological Insulators
Institute of Scientific and Technical Information of China (English)
YU Rui
2011-01-01
The Hall effect, the anomalous Hall effect （AHE） and the spin Hall effect are thndamental transport processes in solids arising from the Lorentz force and the spin-orbit coupling respectively. The AHE, in which a voltage transverse to the electric current appears even in the absence of an external magnetic field, was first detected in ferromagnetic （FM） metals in 1881 and later found to arise from the spin-orbit coupling （SOC） between the current and magnetic moments.
Quantization of Spinning Particle with Anomalous Magnetic Momentum
Gitman, D M
1993-01-01
A generalization of the pseudoclassical action of a spinning particle in the presence of an anomalous magnetic moment is given. The leading considerations, to write the action, are gotten from the path integral representation for the causal Green's function of the generalized (by Pauli) Dirac equation for the particle with anomalous magnetic momentum in an external electromagnetic field. The action can be written in reparametrization and supergauge invariant form. Both operator (Dirac) and path-integral (BFV) quantization are discussed. The first one leads to the Dirac-Pauli equation, whereas the second one gives the corresponding propagator. One of the nontrivial points in this case is that both quantizations schemes demand for consistency to take into account an operators ordering problem.
How to Introduce the Magnetic Dipole Moment
Bezerra, M.; Kort-Kamp, W. J. M.; Cougo-Pinto, M. V.; Farina, C.
2012-01-01
We show how the concept of the magnetic dipole moment can be introduced in the same way as the concept of the electric dipole moment in introductory courses on electromagnetism. Considering a localized steady current distribution, we make a Taylor expansion directly in the Biot-Savart law to obtain, explicitly, the dominant contribution of the…
Magnetic moment of the Roper resonance
Energy Technology Data Exchange (ETDEWEB)
Bauer, T. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet, D-55099 Mainz (Germany); Gegelia, J., E-mail: gegelia@kph.uni-mainz.de [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet, D-55099 Mainz (Germany); Institut fuer Theoretische Physik II, Ruhr-Universitaet Bochum, 44780 Bochum (Germany); High Energy Physics Institute of TSU, 0186 Tbilisi, Georgia (United States); Scherer, S. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet, D-55099 Mainz (Germany)
2012-08-29
The magnetic moment of the Roper resonance is calculated in the framework of a low-energy effective field theory of the strong interactions. A systematic power-counting procedure is implemented by applying the complex-mass scheme.
Magnetic moment of the Roper resonance
Bauer, T.; Gegelia, J.; Scherer, S.
2012-01-01
The magnetic moment of the Roper resonance is calculated in the framework of a low-energy effective field theory of the strong interactions. A systematic power-counting procedure is implemented by applying the complex-mass scheme.
An experimental review of hyperon magnetic moments
International Nuclear Information System (INIS)
Hyperon magnetic moments are important probes for studying the structure of baryons. In this talk, I shall briefly describe how the measurements are made and discuss the current status of the determinations
Quantized Anomalous Hall Effect in Magnetic Topological Insulators
Institute of Scientific and Technical Information of China (English)
YU Rui
2011-01-01
@@ The Hall effect, the anomalous Hall effect (AHE) and the spin Hall effect are fundamental transport processes in solids arising from the Lorentz force and the spin-orbit coupling respectively.The AHE, in which a voltage transverse to the electric current appears even in the absence of an external magnetic field, was first detected in ferromagnetic (FM) metals in 1881 and later found to arise from the spin-orbit coupling (SOC) between the current and magnetic moments.Recent progress on the mechanism of AHE has established a link between the AHE and the topological nature of the Hall current by adopting the Berry-phase concepts in close analogy to the intrinsic spin Hall effect.Given the experimental discovery of the quantum Hall and the quantum spin Hall effects, it is natural to ask whether the AHE can also be quantized.In a quantized anomalous Hall (QAH) insulator, spontaneous magnetic moments and spin-orbit coupling combine to give rise to a topologically non-trivial electronic structure, leading to the quantized Hall effect without any external magnetic field.
Rapid Characterization of Magnetic Moment of Cells for Magnetic Separation
Ooi, Chinchun; Earhart, Christopher M.; Wilson, Robert J.; Wang, Shan X.
2013-01-01
NCI-H1650 lung cancer cell lines labeled with magnetic nanoparticles via the Epithelial Cell Adhesion Molecule (EpCAM) antigen were previously shown to be captured at high efficiencies by a microfabricated magnetic sifter. If fine control and optimization of the magnetic separation process is to be achieved, it is vital to be able to characterize the labeled cells’ magnetic moment rapidly. We have thus adapted a rapid prototyping method to obtain the saturation magnetic moment of these cells....
Magnetic moment nonconservation in magnetohydrodynamic turbulence models.
Dalena, S; Greco, A; Rappazzo, A F; Mace, R L; Matthaeus, W H
2012-07-01
The fundamental assumptions of the adiabatic theory do not apply in the presence of sharp field gradients or in the presence of well-developed magnetohydrodynamic turbulence. For this reason, in such conditions the magnetic moment μ is no longer expected to be constant. This can influence particle acceleration and have considerable implications in many astrophysical problems. Starting with the resonant interaction between ions and a single parallel propagating electromagnetic wave, we derive expressions for the magnetic moment trapping width Δμ (defined as the half peak-to-peak difference in the particle magnetic moments) and the bounce frequency ω(b). We perform test-particle simulations to investigate magnetic moment behavior when resonance overlapping occurs and during the interaction of a ring-beam particle distribution with a broadband slab spectrum. We find that the changes of magnetic moment and changes of pitch angle are related when the level of magnetic fluctuations is low, δB/B(0) = (10(-3),10(-2)), where B(0) is the constant and uniform background magnetic field. Stochasticity arises for intermediate fluctuation values and its effect on pitch angle is the isotropization of the distribution function f(α). This is a transient regime during which magnetic moment distribution f(μ) exhibits a characteristic one-sided long tail and starts to be influenced by the onset of spatial parallel diffusion, i.e., the variance grows linearly in time as in normal diffusion. With strong fluctuations f(α) becomes completely isotropic, spatial diffusion sets in, and the f(μ) behavior is closely related to the sampling of the varying magnetic field associated with that spatial diffusion.
Electric and Magnetic Dipole Moments
CERN. Geneva
2005-01-01
The stringent limit on the electric dipole moment of the neutron forced the issue on the strong CP-problem. The most elegant solution of which is the axion field proposed by Peccei and Quinn. The current limit on the QCD parameter theta coming from the limit on the neutron EDM is of order 10-10. I am going to describe the present status on the neutron EDM searches and further prospects on getting down to theta_qcd sensitivity of 10-13 with the new deuteron EDM in storage rings proposal. For completeness the current status and prospects of the muon g-2 experiment will also be given.
Non-planar anomalous dimension of twist-2 operators: higher moments at four loops
Velizhanin, V N
2014-01-01
We compute the non-planar contribution to the anomalous dimension of the eight moment of the twist-2 operators in N=4 supersymmetric Yang-Mills theory at four loops. This result was obtained from the calculations of some elements of the anomalous dimension matrix for twist-2 operators with the help of a relations between its elements and eigenvalues. The properties of the obtained result and a possible relations with a planar results are discussed.
Constraining the neutrino magnetic dipole moment from white dwarf pulsations
Energy Technology Data Exchange (ETDEWEB)
Córsico, A.H.; Althaus, L.G. [Grupo de Evolución Estelar y Pulsaciones, Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, (1900) La Plata (Argentina); Bertolami, M.M. Miller [Instituto de Astrofísica La Plata, CONICET-UNLP, Paseo del Bosque s/n, (1900) La Plata (Argentina); Kepler, S.O. [Departamento de Astronomia, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, Porto Alegre 91501-970, RS (Brazil); García-Berro, E., E-mail: acorsico@fcaglp.unlp.edu.ar, E-mail: althaus@fcaglp.unlp.edu.ar, E-mail: marcelo@MPA-Garching.MPG.DE, E-mail: kepler@if.ufrgs.br, E-mail: enrique.garcia-berro@upc.edu [Departament de Física Aplicada, Universitat Politècnica de Catalunya, c/Esteve Terrades 5, 08860, Castelldefels (Spain)
2014-08-01
Pulsating white dwarf stars can be used as astrophysical laboratories to constrain the properties of weakly interacting particles. Comparing the cooling rates of these stars with the expected values from theoretical models allows us to search for additional sources of cooling due to the emission of axions, neutralinos, or neutrinos with magnetic dipole moment. In this work, we derive an upper bound to the neutrino magnetic dipole moment (μ{sub ν}) using an estimate of the rate of period change of the pulsating DB white dwarf star PG 1351+489. We employ state-of-the-art evolutionary and pulsational codes which allow us to perform a detailed asteroseismological period fit based on fully DB white dwarf evolutionary sequences. Plasmon neutrino emission is the dominant cooling mechanism for this class of hot pulsating white dwarfs, and so it is the main contributor to the rate of change of period with time (Pidot) for the DBV class. Thus, the inclusion of an anomalous neutrino emission through a non-vanishing magnetic dipole moment in these sequences notably influences the evolutionary timescales, and also the expected pulsational properties of the DBV stars. By comparing the theoretical Pidot value with the rate of change of period with time of PG 1351+489, we assess the possible existence of additional cooling by neutrinos with magnetic dipole moment. Our models suggest the existence of some additional cooling in this pulsating DB white dwarf, consistent with a non-zero magnetic dipole moment with an upper limit of μ{sub ν} ∼< 10{sup -11} μ{sub B}. This bound is somewhat less restrictive than, but still compatible with, other limits inferred from the white dwarf luminosity function or from the color-magnitude diagram of the Globular cluster M5. Further improvements of the measurement of the rate of period change of the dominant pulsation mode of PG 1351+489 will be necessary to confirm our bound.
Near-Field Magnetic Dipole Moment Analysis
Harris, Patrick K.
2003-01-01
This paper describes the data analysis technique used for magnetic testing at the NASA Goddard Space Flight Center (GSFC). Excellent results have been obtained using this technique to convert a spacecraft s measured magnetic field data into its respective magnetic dipole moment model. The model is most accurate with the earth s geomagnetic field cancelled in a spherical region bounded by the measurement magnetometers with a minimum radius large enough to enclose the magnetic source. Considerably enhanced spacecraft magnetic testing is offered by using this technique in conjunction with a computer-controlled magnetic field measurement system. Such a system, with real-time magnetic field display capabilities, has been incorporated into other existing magnetic measurement facilities and is also used at remote locations where transport to a magnetics test facility is impractical.
Nucleon Magnetic Moments and Electric Polarizabilities
Energy Technology Data Exchange (ETDEWEB)
W Detmold, B C Tiburzi, A Walker-Loud
2010-06-01
Electromagnetic properties of the nucleon are explored with lattice QCD using a novel technique. Focusing on background electric fields, we show how the electric polarizability can be extracted from nucleon correlation functions. A crucial step concerns addressing contributions from the magnetic moment, which affects the relativistic propagation of nucleons in electric fields. By properly handing these contributions, we can determine both magnetic moments and electric po larizabilities. Lattice results from anisotropic clover lattices are presented. Our method is not limited to the neutron; we show results for the proton as well.
Anomalous magnetoresistance in magnetized topological insulator cylinders
Energy Technology Data Exchange (ETDEWEB)
Siu, Zhuo Bin, E-mail: a0018876@nus.edu.sg [NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456 (Singapore); Data Storage Institute, Agency for Science, Technology and Research, Singapore 117608 (Singapore); Jalil, Mansoor B. A. [NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456 (Singapore)
2015-05-07
The close coupling between the spin and momentum degrees of freedom in topological insulators (TIs) presents the opportunity for the control of one to manipulate the other. The momentum can, for example, be confined on a curved surface and the spin influenced by applying a magnetic field. In this work, we study the surface states of a cylindrical TI magnetized in the x direction perpendicular to the cylindrical axis lying along the z direction. We show that a large magnetization leads to an upwards bending of the energy bands at small |k{sub z}|. The bending leads to an anomalous magnetoresistance where the transmission between two cylinders magnetized in opposite directions is higher than when the cylinders are magnetized at intermediate angles with respect to each other.
Neutrino masses, magnetic moments, and horizontal symmetries
International Nuclear Information System (INIS)
We investigate the general structure of the neutrino mass and magnetic matrices in the presence of an unbroken horizontal symmetry. In particular, we study the compatibility of masslessness induced by such a symmetry and a non-zero magnetic moment. We show that in this case at least two of the charged leptons must have equal masses. Furthermore, we give a general definition of Dirac neutrinos and demonstrate that they are not necessarily associated with a lepton number. (Author) 15 refs
Status and perspectives of neutrino magnetic moments
Studenikin, Alexander
2016-01-01
Basic theoretical and experimental aspects of neutrino magnetic moments are reviewed, including the present best upper bounds from reactor experiments and astrophysics. An interesting effect of neutrino spin precession and oscillations induced by the background matter transversal current or polarization is also discussed.
Transition radiation of the neutrino magnetic moment
Sakuda, M.; Kurihara, Y
1994-01-01
If the neutrino has a finite mass and a magnetic moment it would produce transition radiation when crossing the interface between two media. We found that the probability of transition radiation is larger by an order of magnitude using the quantum theory than that recently reported by one of us using classical electrodynamics, and that the energy spectrum of the radiation is nearly uniform.
Interpreting magnetic data by integral moments
Tontini, F. Caratori; Pedersen, L. B.
2008-09-01
The use of the integral moments for interpreting magnetic data is based on a very elegant property of potential fields, but in the past it has not been completely exploited due to problems concerning real data. We describe a new 3-D development of previous 2-D results aimed at determining the magnetization direction, extending the calculation to second-order moments to recover the centre of mass of the magnetization distribution. The method is enhanced to reduce the effects of the regional field that often alters the first-order solutions. Moreover, we introduce an iterative correction to properly assess the errors coming from finite-size surveys or interaction with neighbouring anomalies, which are the most important causes of the failing of the method for real data. We test the method on some synthetic examples, and finally, we show the results obtained by analysing the aeromagnetic anomaly of the Monte Vulture volcano in Southern Italy.
Magnetic moment of iron in metallic environments
International Nuclear Information System (INIS)
Rare-earth iron nitrides are emerging as an important class of magnetic materials. In certain rare-earth iron compounds, the insertion of small atoms such as nitrogen and boron has resulted in significant changes in the magnetic properties in the form of higher Curie temperatures, enhanced magnetic moments, and stronger anisotropies. In an attempt to understand some of the above, we have focused on two nitride phases of Fe, namely Fe4N (cubic) and Fe16N2 (tetragonal). For the Fe16N2 phase, the average Fe moment reported by different experimental groups varies over a wide range of values, from 2.3μB to 3.5μB. We will discuss some of the recent experiments and examine some related theoretical questions with regard to Fe having such an unusually large moment in a metallic environment. Employing a Hubbard-Stoner-like model in addition to local-density results, it is shown that an unusually large on-site Coulomb repulsion is necessary if one is to obtain a moment as large as 3.5μB. (c) 2000 The American Physical Society
Noncommutative magnetic moment of charged particles
Adorno, T C; Shabad, A E; Vassilevich, D V
2011-01-01
It has been argued, that in noncommutative field theories sizes of physical objects cannot be taken smaller than an elementary length related to noncommutativity parameters. By gauge-covariantly extending field equations of noncommutative U(1)_*-theory to the presence of external sources, we find electric and magnetic fields produces by an extended charge. We find that such a charge, apart from being an ordinary electric monopole, is also a magnetic dipole. By writing off the existing experimental clearance in the value of the lepton magnetic moments for the present effect, we get the bound on noncommutativity at the level of 10^4 TeV.
Anomalous Josephson Hall effect in magnet/triplet superconductor junctions
Yokoyama, Takehito
2015-01-01
We investigate anomalous Hall effect in a magnet coupled to a triplet superconductor under phase gradient. It is found that the anomalous Hall supercurrent arises from non-trivial structure of the magnetization. The magnetic structure manifested in the Hall supercurrent is characterized by even order terms of the exchange coupling, essentially different from that discussed in the context of anomalous Hall effect, reflecting the disspationless nature of supercurrent. We also discuss a possible...
Instantaneous Power Radiated from Magnetic Dipole Moments
Morley, Peter D
2014-01-01
We compute the power radiated per unit solid angle of a moving magnetic dipole moment, and its instantaneous radiated power, both non-relativistically and relativistically. This is then applied to various interesting situations: solar neutrons, electron synchrotrons and cosmological Dirac neutrinos. Concerning the latter, we show that hypothesized early-universe Big Bang conditions allow for neutrino radiation cooling and provide an energy loss-mechanism for subsequent neutrino condensation.
Energy Technology Data Exchange (ETDEWEB)
Bouten, M. (Limburgs Universitair Centrum (Belgium)); Bouten, M.C. (Centre d' Etude de l' Energie Nucleaire, Mol (Belgium))
1982-01-01
The dependence of the magnetic moment of /sup 11/B on the characteristics of the nucleon-nucleon interaction is investigated in the framework of the shell model. This leads to the construction of a new central two-body interaction for use in variational calculations for nuclei in the second half of the p shell. An intermediate-coupling calculation in a projected Hartree-Fock basis for the ground state of /sup 11/B is carried out using the new interaction.
Neutrino Moments and the Magnetic Primakoff Effect
Domokos, G.; Kovesi-Domokos, S.
1996-01-01
If different species of neutrinos possess transition magnetic moments, a conversion between species can occur in the Coulomb field of a nucleus. In the case of Dirac neutrinos this corresponds to an active to sterile conversion, whereas in the case of Majorana neutrinos, the conversion takes place between active species. The conversion cross sections grow with the energy of the incident neutrino. The formalism is also applied to a new type of experiment designed to test the existence of the `...
Neutrino moments and the magnetic Primakoff effect
Domokos, Gabor K
1997-01-01
If different species of neutrinos possess transition magnetic moments, a conversion between species can occur in the Coulomb field of a nucleus. In the case of Dirac neutrinos this corresponds to an active to sterile conversion, whereas in the case of Majorana neutrinos, the conversion takes place between active species. The conversion cross sections grow with the energy of the incident neutrino. The formalism is also applied to a new type of experiment designed to test the existence of the ``KARMEN anomaly''.
Neutrino moments and the magnetic Primakoff effect
International Nuclear Information System (INIS)
If different species of neutrinos possess transition magnetic moments, a conversion between species can occur in the Coulomb field of a nucleus. The conversion cross sections grow with the energy of the incident neutrino. The formalism is also applied to a new type of experiment designed to test the existence of the open-quotes KARMEN anomaly.close-quote close-quote copyright 1997 The American Physical Society
Measurement of Short Living Baryon Magnetic Moment using Bent Crystals at SPS and LHC
Burmistrov, L; Ivanov, Yu; Massacrier, L; Robbe, P; Scandale, W; Stocchi, A
2016-01-01
The magnetic moments of baryons containing u,d and s quarks have been extensively studied and measured. The experimental results are all obtained by a well-assessed method that consists in measuring the polarisation vector of the incoming particles and the precession angle when the particle is travelling through an intense magnetic field. The polarization is evaluated by analysing the angular distribution of the decay products. No measurement of magnetic moments of charm or beauty baryons (and τ leptons) has been performed so far. The main reason is the lifetimes of charm/beauty baryons, too short to measure the magnetic moment by standard techniques. Historically, the prediction of baryon magnetic moments was one of the striking successes of the quark model. The importance of the measurement of heavy quark magnetic moment is to test the possibility that the charmed and/or beauty quarks has an anomalous magnetic moment, arising if those quarks are composite objects. Measurements on magnetic moments of heav...
Anomalous magnetic properties of VOx multiwall nanotubes
Demishev, S. V.; Chernobrovkin, A. L.; Glushkov, V. V.; Goodilin, E. A.; Grigorieva, A. V.; Ishchenko, T. V.; Kuznetsov, A. V.; Sluchanko, N. E.; Tretyakov, Yu D.; Semeno, A. V.
2010-01-01
Basing on the high frequency (60 GHz) electron spin resonance (ESR) and magnetic susceptibility study of the VOx multiwall nanotubes (VOx-NTs) in the range 4.2-300 K we report the ESR evidence of the presence of the antiferromagnetic V4+ dimers in VOx-NTs and the observation of an anomalous low temperature (T<50 K) growth of the magnetic susceptibility for V4+ quasi-free spins, which obey power law χ(T)~1/Tα with the exponent αapprox0.6. The estimates of the concentrations for various spin species (clusters) indicate that the non-interacting dimers should be an essential element in the VOx-NTs structure. The possibility of the disorder driven quantum critical regime in VOx-NTs is discussed.
Porsev, S G; Flambaum, V V
2010-01-01
We have considered a mechanism for inducing a time-reversal violating electric dipole moment (EDM) in atoms through the interaction of a nuclear EDM (d_N) with the hyperfine interaction, the "magnetic moment effect". We have derived the operator for this interaction and presented analytical formulas for the matrix elements between atomic states. Induced EDMs in the diamagnetic atoms 129Xe, 171Yb, 199Hg, 211Rn, and 225Ra have been calculated numerically. From the experimental limits on the atomic EDMs of 129Xe and 199Hg, we have placed the following constraints on the nuclear EDMs, |d_N(129Xe)|< 1.1 * 10^{-21} |e|cm and |d_N(199Hg)|< 2.8 * 10^{-24} |e|cm.
Shuffle dislocation induced magnetic moment in graphene
Energy Technology Data Exchange (ETDEWEB)
Lopez-Sancho, M.P., E-mail: pilar@icmm.csic.e [Instituto de Ciencia de Materiales de Madrid-CSIC, C/Sor Juana Ines de la Cruz 3, 28049 Madrid (Spain); Juan, F. de; Vozmediano, M.A.H. [Instituto de Ciencia de Materiales de Madrid-CSIC, C/Sor Juana Ines de la Cruz 3, 28049 Madrid (Spain)
2010-05-15
Graphene, a honeycomb arrangement of carbon atoms, is a promising material for nanoelectronics applications due to its unusual electronic properties. Recent experiments performed on suspended graphene indicate the existence of intrinsic defects on the samples. It is known that lattice defects such as vacancies or voids leaving unpaired atoms, lead to the formation of local magnetic moments (Vozmediano et al., 2005). The existence and ordering of these moments is largely determined by the bipartite character of the honeycomb lattice seen as two interpenetrating triangular sublattices. Dislocations made by pentagon-heptagon pairs or octagons with an unpaired atom have been studied recently and found to be stable in the graphene lattice (Carpio et al., 2008). These defects frustrate the sublattice structure and affect the magnetic properties of graphene. We study the magnetic properties of graphene in the presence of these defects. The system is described by a p{sub z} tight-binding model with electron-electron interactions modelled by a Hubbard term. Spin-polarized mean-field solutions are investigated within an unrestricted Hartree-Fock approximation.
Huang, S.; Ma, Y. Q.; Xu, S. T.
2015-12-01
Well-dispersed uniform cobalt ferrite nanoparticles were synthesized by thermal decomposition of a metal-organic salt in organic solvent with a high boiling point, and characterized by XRD, TEM and detailed magnetic measurements. The moments of CoFe2O4 nanoparticles consist of the core and canted surface moments below 200 K, and the exchange-coupling between the surface and core spins enhanced the remanence (Mr) to saturation (Ms) magnetization ratio (Mr/Ms) at the temperature of 10 K. Interestingly, the anomalous memory effect was observed in a broad temperature range which can be attributed to the relaxation of surface spins below 200 K and the one from the moments of magnetically ordered entity larger than one particle above 200 K.
Development of a Thin Film Magnetic Moment Reference Material.
Pappas, D P; Halloran, S T; Owings, R R; da Silva, F C S
2008-01-01
In this paper we present the development of a magnetic moment reference material for low moment magnetic samples. We first conducted an inter-laboratory comparison to determine the most useful sample dimensions and magnetic properties for common instruments such as vibrating sample magnetometers (VSM), SQUIDs, and alternating gradient field magnetometers. The samples were fabricated and then measured using a vibrating sample magnetometer. Their magnetic moments were calibrated by tracing back to the NIST YIG sphere, SRM 2853. PMID:27096108
Magnetic resonance signal moment determination using the Earth's magnetic field
Fridjonsson, Einar Orn
2015-03-01
We demonstrate a method to manipulate magnetic resonance data such that the moments of the signal spatial distribution are readily accessible. Usually, magnetic resonance imaging relies on data acquired in so-called k-space which is subsequently Fourier transformed to render an image. Here, via analysis of the complex signal in the vicinity of the centre of k-space we are able to access the first three moments of the signal spatial distribution, ultimately in multiple directions. This is demonstrated for biofouling of a reverse osmosis (RO) membrane module, rendering unique information and an early warning of the onset of fouling. The analysis is particularly applicable for the use of mobile magnetic resonance spectrometers; here we demonstrate it using an Earth\\'s magnetic field system.
Magnetic resonance signal moment determination using the Earth's magnetic field
Fridjonsson, E. O.; Creber, S. A.; Vrouwenvelder, J. S.; Johns, M. L.
2015-03-01
We demonstrate a method to manipulate magnetic resonance data such that the moments of the signal spatial distribution are readily accessible. Usually, magnetic resonance imaging relies on data acquired in so-called k-space which is subsequently Fourier transformed to render an image. Here, via analysis of the complex signal in the vicinity of the centre of k-space we are able to access the first three moments of the signal spatial distribution, ultimately in multiple directions. This is demonstrated for biofouling of a reverse osmosis (RO) membrane module, rendering unique information and an early warning of the onset of fouling. The analysis is particularly applicable for the use of mobile magnetic resonance spectrometers; here we demonstrate it using an Earth's magnetic field system.
Abdallah, J; Adam, W; Adzic, P; Albrecht, T; Alderweireld, T; Alemany-Fernandez, R; Allmendinger, T; Allport, P P; Amaldi, Ugo; Amapane, N; Amato, S; Anashkin, E; Andreazza, A; Andringa, S; Anjos, N; Antilogus, P; Apel, W D; Arnoud, Y; Ask, S; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Ballestrero, A; Bambade, P; Barbier, R; Bardin, Dimitri Yuri; Barker, G; Baroncelli, A; Battaglia, Marco; Baubillier, M; Becks, K H; Begalli, M; Behrmann, A; Ben-Haim, E; Benekos, N C; Benvenuti, Alberto C; Bérat, C; Berggren, M; Berntzon, L; Bertrand, D; Besançon, M; Besson, N; Bloch, D; Blom, M; Bluj, M; Bonesini, M; Boonekamp, M; Booth, P S L; Borisov, G; Botner, O; Bouquet, B; Bowcock, T J V; Boyko, I; Bracko, M; Brenner, R; Brodet, E; Brückman, P; Brunet, J M; Bugge, L; Buschmann, P; Calvi, M; Camporesi, T; Canale, V; Carena, F; Castro, N; Cavallo, F R; Chapkin, M M; Charpentier, P; Checchia, P; Chierici, R; Shlyapnikov, P; Chudoba, J; Chung, S U; Cieslik, K; Collins, P; Contri, R; Cosme, G; Cossutti, F; Costa, M J; Crennell, D J; Cuevas-Maestro, J; D'Hondt, J; Dalmau, J; Da Silva, T; Da Silva, W; Della Ricca, G; De Angelis, A; de Boer, Wim; De Clercq, C; De Lotto, B; De Maria, N; De Min, A; De Paula, L S; Di Ciaccio, L; Di Simone, A; Doroba, K; Drees, J; Dris, M; Eigen, G; Ekelöf, T J C; Ellert, M; Elsing, M; Espirito-Santo, M C; Fanourakis, G K; Fassouliotis, D; Feindt, M; Fernández, J; Ferrer, A; Ferro, F; Flagmeyer, U; Föth, H; Fokitis, E; Fulda-Quenzer, F; Fuster, J A; Gandelman, M; García, C; Gavillet, P; Gazis, E N; Gokieli, R; Golob, B; Gómez-Ceballos, G; Gonçalves, P; Graziani, E; Grosdidier, G; Grzelak, K; Guy, J; Haag, C; Hallgren, A; Hamacher, K; Hamilton, K; Haug, S; Hauler, F; Hedberg, V; Hennecke, M; Herr, H; Hoffman, J; Holmgren, S O; Holt, P J; Houlden, M A; Hultqvist, K; Jackson, J N; Jarlskog, G; Jarry, P; Jeans, D; Johansson, E K; Johansson, P D; Jonsson, P; Joram, C; Jungermann, L; Kapusta, F; Katsanevas, S; Katsoufis, E C; Kernel, G; Kersevan, B P; Kerzel, U; Kiiskinen, A P; King, B T; Kjaer, N J; Kluit, P; Kokkinias, P; Kourkoumelis, C; Kuznetsov, O; Krumshtein, Z; Kucharczyk, M; Lamsa, J; Leder, G; Ledroit, F; Leinonen, L; Leitner, R; Lemonne, J; Lepeltier, V; Lesiak, T; Liebig, W; Liko, D; Lipniacka, A; Lopes, J H; López, J M; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J; Malek, A; Maltezos, S; Mandl, F; Marco, J; Marco, R; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Masik, J; Mastroyiannopoulos, N; Matorras, F; Matteuzzi, C; Mazzucato, F; Mazzucato, M; McNulty, R; Meroni, C; Migliore, E; Mitaroff, W A; Mjörnmark, U; Moa, T; Moch, M; Mönig, K; Monge, R; Montenegro, J; Moraes, D; Moreno, S; Morettini, P; Müller, U; Münich, K; Mulders, M; Mundim, L; Murray, W; Muryn, B; Myatt, G; Myklebust, T; Nassiakou, M; Navarria, Francesco Luigi; Nawrocki, K; Nicolaidou, R; Nikolenko, M; Oblakowska-Mucha, A; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, R; Österberg, K; Ouraou, A; Oyanguren, A; Paganoni, M; Paiano, S; Palacios, J P; Palka, H; Papadopoulou, T D; Pape, L; Parkes, C; Parodi, F; Parzefall, U; Passeri, A; Passon, O; Peralta, L; Perepelitsa, V F; Perrotta, A; Petrolini, A; Piedra, J; Pieri, L; Pierre, F; Pimenta, M; Piotto, E; Podobnik, T; Poireau, V; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Pukhaeva, N; Pullia, Antonio; Rames, J; Ramler, L; Read, A; Rebecchi, P; Rehn, J; Reid, D; Reinhardt, R; Renton, P B; Richard, F; Rídky, J; Rivero, M; Rodríguez, D; Romero, A; Ronchese, P; Roudeau, P; Rovelli, T; Ruhlmann-Kleider, V; Ryabtchikov, D; Sadovskii, A; Salmi, L; Salt, J; Savoy-Navarro, A; Schwickerath, U; Segar, A; Sekulin, R L; Siebel, M; Sissakian, A N; Smadja, G; Smirnova, O G; Sokolov, A; Sopczak, A; Sosnowski, R; Spassoff, Tz; Stanitzki, M; Stocchi, A; Strauss, J; Stugu, B; Szczekowski, M; Szeptycka, M; Szumlak, T; Tabarelli de Fatis, T; Taffard, A C; Tegenfeldt, F; Timmermans, J; Tkatchev, L G; Tobin, M; Todorovova, S; Tomé, B; Tonazzo, A; Tortosa, P; Travnicek, P; Treille, D; Tristram, G; Trochimczuk, M; Troncon, C; Turluer, M L; Tyapkin, I A; Tyapkin, P; Tzamarias, S; Uvarov, V; Valenti, G; van Dam, P; Van Eldik, J; Van Lysebetten, A; Van Remortel, N; Van Vulpen, I; Vegni, G; Veloso, F; Venus, W A; Verdier, P; Verzi, V; Vilanova, D; Vitale, L; Vrba, V; Wahlen, H; Washbrook, A J; Weiser, C; Wicke, D; Wickens, J H; Wilkinson, G; Winter, M; Witek, M; Yushchenko, O P; Zalewska-Bak, A; Zalewski, P; Zavrtanik, D; Zhuravlov, V; Zimin, N I; Zintchenko, A; Zupan, M
2004-01-01
Tau-pair production in the process e+e- -> e+e-tau+tau- was studied using data collected by the DELPHI experiment at LEP2 during the years 1997 - 2000. The corresponding integrated luminosity is 650 pb^{-1}. The values of the cross-section obtained are found to be in agreement with QED predictions. Limits on the anomalous magnetic and electric dipole moments of the tau lepton are deduced.
$H \\rightarrow \\tau^+ \\tau^- \\gamma$ as a Probe of the $\\tau$ Magnetic Dipole Moment
Galon, Iftah; Tait, Tim M P
2016-01-01
Low energy observables involving the Standard Model fermions which are chirality-violating, such as anomalous electromagnetic moments, necessarily involve an insertion of the Higgs in order to maintain $SU(2) \\times U(1)$ gauge invariance. As the result, the properties of the Higgs boson measured at the LHC impact our understanding of the associated low-energy quantities. We illustrate this feature with a discussion of the electromagnetic moments of the $\\tau$-lepton, as probed by the rare decay $H \\rightarrow \\tau^+ \\tau^- \\gamma$. We assess the feasibility of measuring this decay at the LHC, and show that the current bounds from lower energy measurements imply that $13~\\rm{TeV}$ running is very likely to improve our understanding of new physics contributing to the anomalous magnetic moment of the tau.
Anomalous transport effects in magnetically-confined plasma columns
International Nuclear Information System (INIS)
The evolution of density structure in a magnetized plasma column is analyzed accounting for anomalous diffusion due to the lower hybrid drift instability. The plasma column is found to be divided into regions of classical, anomalous, and intermediate diffusivity. The bulk behavior, described in terms of radial confinement time, depends most sensitively upon the particle line density (ion/cm). For broad plasmas (large line density), the transport is characteristic of classical diffusion, and for slender plasmas (small line density) the transport is characteristic of anomalous diffusion. For intermediate line densities, the transport undertakes a rapid transition from classical to anomalous. Correlations between the theoretical results and past experiments are described
Sigma-lambda transition magnetic moment
International Nuclear Information System (INIS)
The Primakoff effect was utilized in a measurement of the Σ0-Λ transition magnetic moment at the Fermilab neutral hyperon facility. A beam containing Λ's with average momenta of 150 GeV/c passed through a target. A small fraction of them interacted with the Coulomb field of the target nuclei to produce a Σ0 which subsequently decayed via the process:Σ0 → Λγ. A sample of 5 x 105 Λγ events were analyzed for 7 different targets, and yielded a total of 2028 +/- 139 Coulomb-produced Σ0's. The total Primakoff cross sections for Λ on beryllium, tin, and lead were determined to be σ/sub Be/ = 0.033 +/- 0.022 mb, σ/sub Sn/ = 3.28 +/- 0.34 mb, and σ/sub Pb/ = 9.20 +/- 0.81 mb. There is an additional 7% systematic uncertainty. The Primakoff formalism predicts σ proportional to Z2 μ/sub ΣΛ/ 2, where μ/sub Σλ/ is the Σ0-Λ transition magnetic moment. A least-squares fit of the experimental cross sections to this functional form yielded absolute value of μ/sub ΣΛ/ = (1.59 +/- 0.05 +/- 0.05) nuclear magnetons. This corresponds to a Σ0 lifetime of tau = (0.76 +/- 0.05 +/- 0.05) x 10-19 seconds or a radiative width of Gamma = (8.6 +/- 0.6 +/- 0.6) keV, where the uncertainties are statistical and systematic, respectively. An additional uncertainty due to approximations in the Primakoff formalism applies to these derived quantities: <5% on tau and Gamma, and <2.5% on absolute value of μ/sub ΣΛ/
Morales-Casique, E.; Lezama-Campos, J. L.; Guadagnini, A.; Neuman, S. P.
2013-05-01
Modeling tracer transport in geologic porous media suffers from the corrupt characterization of the spatial distribution of hydrogeologic properties of the system and the incomplete knowledge of processes governing transport at multiple scales. Representations of transport dynamics based on a Fickian model of the kind considered in the advection-dispersion equation (ADE) fail to capture (a) the temporal variation associated with the rate of spreading of a tracer, and (b) the distribution of early and late arrival times which are often observed in field and/or laboratory scenarios and are considered as the signature of anomalous transport. Elsewhere we have presented exact stochastic moment equations to model tracer transport in randomly heterogeneous aquifers. We have also developed a closure scheme which enables one to provide numerical solutions of such moment equations at different orders of approximations. The resulting (ensemble) average and variance of concentration fields were found to display a good agreement against Monte Carlo - based simulation results for mildly heterogeneous (or well-conditioned strongly heterogeneous) media. Here we explore the ability of the moment equations approach to describe the distribution of early arrival times and late time tailing effects which can be observed in Monte-Carlo based breakthrough curves (BTCs) of the (ensemble) mean concentration. We show that BTCs of mean resident concentration calculated at a fixed space location through higher-order approximations of moment equations display long tailing features of the kind which is typically associated with anomalous transport behavior and are not represented by an ADE model with constant dispersive parameter, such as the zero-order approximation.
Anomalous transport model study of chiral magnetic effects in heavy ion collisions
Sun, Yifeng; Li, Feng
2016-01-01
Using an anomalous transport model for massless quarks, we study the effect of magnetic field on the elliptic flows of quarks and antiquarks in relativistic heavy ion collisions. With initial conditions from a blast wave model and assuming that the strong magnetic field produced in non-central heavy ion collisions can last for a sufficiently long time, we obtain an appreciable electric quadrupole moment in the transverse plane of a heavy ion collision, which subsequently leads to a splitting between the elliptic flows of quarks and antiquarks as expected from the chiral magnetic wave formed in the produced QGP and observed in experiments at the Relativistic Heavy Ion Collider (RHIC).
Numerical modeling of higher order magnetic moments in UXO discrimination
Sanchez, V.; Yaoguo, L.; Nabighian, M.N.; Wright, D.L.
2008-01-01
The surface magnetic anomaly observed in unexploded ordnance (UXO) clearance is mainly dipolar, and consequently, the dipole is the only magnetic moment regularly recovered in UXO discrimination. The dipole moment contains information about the intensity of magnetization but lacks information about the shape of the target. In contrast, higher order moments, such as quadrupole and octupole, encode asymmetry properties of the magnetization distribution within the buried targets. In order to improve our understanding of magnetization distribution within UXO and non-UXO objects and to show its potential utility in UXO clearance, we present a numerical modeling study of UXO and related metallic objects. The tool for the modeling is a nonlinear integral equation describing magnetization within isolated compact objects of high susceptibility. A solution for magnetization distribution then allows us to compute the magnetic multipole moments of the object, analyze their relationships, and provide a depiction of the anomaly produced by different moments within the object. Our modeling results show the presence of significant higher order moments for more asymmetric objects, and the fields of these higher order moments are well above the noise level of magnetic gradient data. The contribution from higher order moments may provide a practical tool for improved UXO discrimination. ?? 2008 IEEE.
Electron Orbital Magnetic Moments in the Armchair Carbon Nanotubes
Institute of Scientific and Technical Information of China (English)
CHEN Jing-Zhe; CHEN Xing; LIU Guang-Nua; HAN Ru-Shan
2008-01-01
@@ Based on the density functional theory, we calculate the band structure of an armchair carbon nanotube in an axial magnetic field. The result shows that there are two kinds of magnetic moments with different symmetries. One is the Aharonov Bohm-type magnetic moment which can be easily understood with classical picture, the other belonging to the valence, and conduction sub-bands should be explained by quantum mechanics. We use an effective mass model to analyse the magnetic moments and by comparing with the result of first-principle calculation, we conclude that the effective mass model is reasonable to estimate the change of the band gap in magnetic fields.
Magnetic Moment Formulas of Baryons Determined by Quantum Numbers
Chang, Yi-Fang
2008-01-01
We propose that the magnetic moment formulas of baryons may be determined by quantum numbers, and obtain three formulas. This is a new type of magnetic moment formula, and agrees better with the experimental values. It is also similar to corresponding mass formulas of hadrons.
Magnetic moments of charm baryons in chiral perturbation theory
International Nuclear Information System (INIS)
Magnetic moments of the charm baryons of the sextet and of the 3*-plet are re-evaluated in the framework of Heavy Hadron Chiral Perturbation Theory (HHCPT). NRQM and broken SU(4) unitary symmetry model are used to obtain tree-level magnetic moments. Calculations of a unitary symmetry part of one-loop contributions to magnetic moments of the charm baryons are performed in detail in terms of the SU(4) couplings of charm baryons to Goldstone bosons. The relations between the magnetic moments of the sextet 1/2 baryons with the one-loop corrections are shown to coincide with the NRQM relations. The correspondence between HHCPT results and those of NRQM and unitary symmetry model is discussed. It is shown that one-loop corrections can effectively be absorbed into the tree-level formulae for the magnetic moments of the charm baryons in the broken SU(4) unitary symmetry model and partially in the NRQM. (author)
Numerical modeling of magnetic moments for UXO applications
Sanchez, V.; Li, Y.; Nabighian, M.; Wright, D.
2006-01-01
The surface magnetic anomaly observed in UXO clearance is mainly dipolar and, consequently, the dipole is the only magnetic moment regularly recovered in UXO applications. The dipole moment contains information about intensity of magnetization but lacks information about shape. In contrast, higher-order moments, such as quadrupole and octupole, encode asymmetry properties of the magnetization distribution within the buried targets. In order to improve our understanding of magnetization distribution within UXO and non-UXO objects and its potential utility in UXO clearance, we present a 3D numerical modeling study for highly susceptible metallic objects. The basis for the modeling is the solution of a nonlinear integral equation describing magnetization within isolated objects. A solution for magnetization distribution then allows us to compute magnetic moments of the object, analyze their relationships, and provide a depiction of the surface anomaly produced by different moments within the object. Our modeling results show significant high-order moments for more asymmetric objects situated at depths typical of UXO burial, and suggest that the increased relative contribution to magnetic gradient data from these higher-order moments may provide a practical tool for improved UXO discrimination.
Object representation and magnetic moments in thin alkali films
Garrett, Douglas C.
2008-10-01
impurities 1/taus and their magnetic cross section sigmas are calculated. We find that single V surface impurities are magnetic while single Mo and Co impurities are non-magnetic. Co surface clusters are magnetic. In chapter 7, thin films of Na, K, Rb and Cs are quench condensed, then covered with 1/100 of a mono-layer of Ti and finally covered with the original host. The magnetization of the films is measured by means of the anomalous Hall effect. An anomalous Hall resistance RAHE is observed for Ti on the surface of K, Rb and Cs and for Ti inside of Cs. Essentially the RAHE varies linearly with the magnetic field and is inversely proportional to the inverse temperature. A small non-linearity of RAHE suggests a Ti moment of about 1microB.
Neutral fermion with magnetic moment in external electromagnetic fields
International Nuclear Information System (INIS)
The Dirac-Pauli equation describes interaction of a substantial neutral fermion having μ magnetic dipole moment with the external electromagnetic field. One determined the precise solutions of that equation and the relevant spectrum of energies for the external magnetic field with axial symmetry. The spin-orbital interaction of a neutral fermion with magnetic moment is shown to govern both the specific features of quantum states and the spectrum of fermion energies. These are the bound states of neutral fermion with magnetic moment in some external electrical fields even if the Dirac-Pauli equation does not have a member with fermion mass
Velizhanin, V N
2014-01-01
We present the result of a calculation for the third and fourth moments of the non-singlet four-loop anomalous dimension of Wilson twist-2 operators in QCD with full color and flavour structures. We discuss also a general expressions for some contributions to the full four-loop anomalous dimension obtained with the help of the method, based on LLL-algorithm, which was proposed earlier by us for the reconstruction of a general form of the anomalous dimension from a fixed values.
International Nuclear Information System (INIS)
Bounds on the anomalous magnetic moment and the electric dipole moment of the τ neutrino are calculated through the reaction e+e-→νν-barγ at the Z1 pole, and in the framework of a left-right symmetric model. The results are based on the recent data reported by the L3 Collaboration at CERN e+e- collider LEP. We find that the bounds are almost independent of the mixing angle φ of the model in the allowed experimental range for this parameter. In addition, the analytical and numerical results for the cross section have never been reported in the literature before
Instability of strong magnetic field and neutrino magnetic dipole moment
Lee, Hyun Kyu
2016-01-01
Vacuum instability of the strong electromagnetic field has been discussed since long time ago. The instability of the strong electric field due to creation of electron pairs is one of the examples, which is known as Schwinger process. What matters are the coupling of particles to the electromagnetic field and the mass of the particle to be produced. The critical electric field for electrons in the minimal coupling is ~ m^2/e . Spin 1/2 neutral particles but with magnetic dipole moments can interact with the electromagnetic field through Pauli coupling. The instability of the particular vacuum under the strong magnetic field can be formulated as the emergence of imaginary parts of the effective potential. In this talk, the development of the imaginary part in the effective potential as a function of the magnetic field strength is discussed for the configurations of the uniform magnetic field and the inhomogeneous magnetic field. Neutrinos are the lightest particle(if not photon or gluon) in the "standard model...
Magnetic moment distributions in α-Fe nanowire array
Institute of Scientific and Technical Information of China (English)
李发伸; 任立元; 牛紫平; 王海新; 王涛
2003-01-01
α-Fe nanowire array has been electrodeposited into anodic aluminum oxide template. The magnetic moment distributions, in the interior and near the extremities of α-Fe nanowire with 60 nm in diameter, have been studied by means of transmission Mossbauer spectroscopy (MS), conversion electron Mossbauer spectroscopy (CEMS) and micromagnetic simulation. Transmission Mossbauer spectrum (MS) shows that the magnetic moments, inside the α-Fe nanowire array, are well parallel to nanowire, while conversion electron Mossbauer spectrum (CEMS) reveals that the magnetic moments, near the extremities of nanowire, diverge from the long axis of wire, and the average diverging angle calculated by the intensity ratio ofthe 2,5 peaks is about 24.0°. Moreover, the magnetic moment distributions of different depths to the top of wire are counted using micromagnetic simulation, which indicates that, the interior magnetic moments are strictly parallel to nanowire, and the closer the magnetic moment to the top of wire, the larger the diverging angle. Magnetic measurement shows that this α-Fe nanowire array represents a strong magnetic anisotropy.
Spacecraft Attitude Stabilization with Piecewise-Constant Magnetic Dipole Moment
Celani, Fabio
2016-05-01
In actual implementations of magnetic control laws for spacecraft attitude stabilization, the time in which Earth magnetic field is measured must be separated from the time in which magnetic dipole moment is generated. The latter separation translates into the constraint of being able to genere only piecewise-constant magnetic dipole moment. In this work we present attitude stabilization laws using only magnetic actuators that take into account of the latter aspect. Both a state feedback and an output feedback are presented, and it is shown that the proposed design allows for a systematic selection of the sampling period.
Lunar magnetic field - Permanent and induced dipole moments
Russell, C. T.; Coleman, P. J., Jr.; Schubert, G.
1974-01-01
Apollo 15 subsatellite magnetic field observations have been used to measure both the permanent and the induced lunar dipole moments. Although only an upper limit of 1.3 x 10 to the 18th gauss-cubic centimeters has been determined for the permanent dipole moment in the orbital plane, there is a significant induced dipole moment which opposes the applied field, indicating the existence of a weak lunar ionosphere.
Pseudoclassical Model of Spinning Particle with Anomalous Magnetic Momentum
Gitman, D M
1993-01-01
A generalization of the pseudoclassical action of a spinning particle in the presence of an anomalous magnetic momentum is given. The action is written in reparametrization and supergauge invariant form. The Dirac quantization, based on the Hamiltonian analyses of the model, leads to the Dirac-Pauli equation for a particle with an anomalous magnetic momentum in an external electromagnetic field. Due to the structure of first-class constraints in that case, the Dirac quantization demands for consistency to take into account an operators ordering problem.
Energy Technology Data Exchange (ETDEWEB)
Hernando, Antonio; Crespo, Patricia [Instituto de Magnetismo Aplicado, UCM-CSIC-ADIF, Las Rozas. P.O. Box 155, 28230 Madrid (Spain); Dept. Fisica de Materiales, Universidad Complutense, Madrid (Spain); Garcia, Miguel Angel [Instituto de Ceramica y Vidrio, CSIC, C/ Kelsen, 5, Madrid 28049 (Spain); Coey, Michael [Trinity College Dublin, Dublin (Ireland); Ayuela, Andres; Echenique, Pedro Miguel [Centro de Fisica de Materiales, CFM-MPC CSIC-UPV/EHU, Donostia International Physics Center (DIPC), 20018 San Sebastian (Spain); Departamento de Fisica de Materiales, Fac. de Quimicas, Universidad del Pais Vasco UPV-EHU, 20018 San Sebastian (Spain)
2011-10-15
In this article we review the exotic magnetism of nanoparticles (NPs) formed by substances that are not magnetic in bulk as described with generality in Section 1. In particular, the intrinsic character of the magnetism observed on capped Au and ZnO NPs is analysed. X-ray magnetic circular dichroism (XMCD) analysis has shown that the magnetic moments are intrinsic and lie in the Au and Zn atoms, respectively, as analysed in Section 2, where the general theoretical ideas are also revisited. Since impurity atoms bonded to the surface act as donor or acceptor of electrons that occupy the surface states, the anomalous magnetic response is analysed in terms of the surface band in Section 3. Finally, Section 4 summarizes our last theoretical proposal. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Birefringence Determination of Magnetic Moments of Magnetotactic Bacteria
Rosenblatt, Charles; de Araujo, F. Flavio Torres; Frankel, Richard B.
1982-01-01
A birefringence technique is used to determine the average magnetic moments of magnetotactic bacteria in culture. Differences in are noted between live and dead bacteria, as well as between normal density and high density samples of live bacteria.
Neutrino Magnetic Moment Contribution to the Neutrino-Deuteron Reaction
Tsuji, K.; Nakamura, S.; Sato, T.; Kubodera, K.; Myhrer, F.
2004-01-01
We study the effect of the neutrino magnetic moment on the neutrino-deuteron breakup reaction, using a method called the standard nuclear physics approach, which has already been well tested for several electroweak processes involving the deuteron.
Magnetic dipole moment and keV neutrino dark matter
Energy Technology Data Exchange (ETDEWEB)
Geng, Chao-Qiang, E-mail: geng@phys.nthu.edu.tw [Department of Physics, National Tsing Hua University, Hsinchu 300, Taiwan (China); Physics Division, National Center for Theoretical Sciences, Hsinchu 300, Taiwan (China); Takahashi, Ryo, E-mail: ryo.takahasi88@gmail.com [Department of Physics, National Tsing Hua University, Hsinchu 300, Taiwan (China)
2012-04-04
We study magnetic dipole moments of right-handed neutrinos in a keV neutrino dark matter model. This model is a simple extension of the standard model with only right-handed neutrinos and a pair of charged particles added. One of the right-handed neutrinos is the candidate of dark matter with a keV mass. Some bounds on the dark matter magnetic dipole moment and model parameters are obtained from cosmological observations.
Magnetic dipole moment and keV neutrino dark matter
Geng, Chao-Qiang
2012-01-01
We study magnetic dipole moments of right-handed neutrinos in a keV neutrino dark matter model. This model is a simple extension of the standard model with only right-handed neutrinos and a pair of charged particles added. One of the right-handed neutrinos is the candidate of dark matter with a keV mass. Some bounds on the dark matter magnetic dipole moment and model parameters are obtained from cosmological observations.
Magnetic dipole moments of the heavy tensor mesons in QCD
Energy Technology Data Exchange (ETDEWEB)
Aliev, T. M., E-mail: taliev@metu.edu.tr [Physics Department, Middle East Technical University, 06531, Ankara (Turkey); Institute of Physics, Baku (Azerbaijan); Barakat, T., E-mail: tbarakat@KSU.EDU.SA [Physics Department, Middle East Technical University, 06531, Ankara (Turkey); Physics and Astronomy Department, King Saud University, Riyadh (Saudi Arabia); Savcı, M., E-mail: savci@metu.edu.tr [Physics Department, Middle East Technical University, 06531, Ankara (Turkey)
2015-11-03
The magnetic dipole moments of the D{sub 2}, and D{sub S{sub 2}}, B{sub 2}, and B{sub S{sub 2}} heavy tensor mesons are estimated in framework of the light cone QCD sum rules. It is observed that the magnetic dipole moments for the charged mesons are larger than that of its neutral counterpart. It is found that the SU(3) flavor symmetry violation is about 10 % in both b and c sectors.
Magnetic dipole moments of the heavy tensor mesons in QCD
International Nuclear Information System (INIS)
The magnetic dipole moments of the D2, and DS2, B2, and BS2 heavy tensor mesons are estimated in framework of the light cone QCD sum rules. It is observed that the magnetic dipole moments for the charged mesons are larger than that of its neutral counterpart. It is found that the SU(3) flavor symmetry violation is about 10 % in both b and c sectors
Magnetic dipole moments of the heavy tensor mesons in QCD
International Nuclear Information System (INIS)
The magnetic dipole moments of the D2, and DS2, B2, and BS2 heavy tensor mesons are estimated in framework of the light cone QCD sum rules. It is observed that the magnetic dipole moments for the charged mesons are larger than that of its neutral counterpart. It is found that the SU(3) flavor symmetry violation is about 10 % in both b and c sectors. (orig.)
Magnetic dipole moments of the heavy tensor mesons in QCD
Aliev, T M; Savcı, M
2015-01-01
The magnetic dipole moments of the ${\\cal D}_2$, and ${\\cal D}_{S_2}$, ${\\cal B}_2$, and ${\\cal B}_{S_2}$ heavy tensor mesons are estimated in framework of the light cone QCD sum rules. It is observed that the magnetic dipole moments for the charged mesons are larger than that of its neutral counterpart. It is found that the $SU(3)$ flavor symmetry violation is about 10\\% in both $b$ and $c$ sectors.
Magnetic moment softening and domain wall resistance in Ni nanowires.
Burton, J D; Sabirianov, R F; Jaswal, S S; Tsymbal, E Y; Mryasov, O N
2006-08-18
We perform ab initio calculations of the electronic structure and conductance of atomic-size Ni nanowires with domain walls only a few atomic lattice constants wide. We show that the hybridization between noncollinear spin states leads to a reduction of the magnetic moments in the domain wall resulting in the enhancement of the domain wall resistance. Experimental studies of the magnetic moment softening may be feasible with modern techniques such as scanning tunneling spectroscopy. PMID:17026271
Resonances and dipole moments in dielectric, magnetic, and magnetodielectric cylinders
DEFF Research Database (Denmark)
Dirksen, A.; Arslanagic, Samel; Breinbjerg, Olav
2011-01-01
An eigenfunction solution to the problem of plane wave scattering by dielectric, magnetic, and magnetodielectric cylinders is used for a systematic investigation of their resonances. An overview of the resonances with electric and magnetic dipole moments, needed in, e.g., the synthesis of metamat......An eigenfunction solution to the problem of plane wave scattering by dielectric, magnetic, and magnetodielectric cylinders is used for a systematic investigation of their resonances. An overview of the resonances with electric and magnetic dipole moments, needed in, e.g., the synthesis...
Magnetic dipole moment estimates for an ancient lunar dynamo
Anderson, K. A.
1983-01-01
The four measured planetary magnetic moments combined with a recent theoretical prediction for dynamo magnetic fields suggests that no dynamo exists in the moon's interior today. For the moon to have had a magnetic moment in the past of sufficient strength to account for at least some of the lunar rock magnetism, the rotation would have been about twenty times faster than it is today and the radius of the fluid, conducting core must have been about 750 km. The argument depends on the validity of the Busse solution to the validity of the MHD problem of planetary dynamos.
Parreno, Assumpta; Tiburzi, Brian C; Wilhelm, Jonas; Chang, Emmanuel; Detmold, William; Orginos, Kostas
2016-01-01
Lattice QCD calculations with background magnetic fields are used to determine the magnetic moments of the octet baryons. Computations are performed at the physical value of the strange quark mass, and two values of the light quark mass, one corresponding to the SU(3) flavor-symmetric point, where the pion mass is ~ 800 MeV, and the other corresponding to a pion mass ~ 450 MeV. The moments are found to exhibit only mild pion-mass dependence when expressed in terms of appropriately chosen magneton units---the natural baryon magneton. This suggests that simple extrapolations can be used to determine magnetic moments at the physical point, and extrapolated results are found to agree with experiment within uncertainties. A curious pattern is revealed among the anomalous baryon magnetic moments which is linked to the constituent quark model, however, careful scrutiny exposes additional features. Relations expected to hold in the large-Nc limit of QCD are studied; and, in one case, the quark model prediction is sig...
Magnetic Instability in Accretion Disks with Anomalous Viscosity
Institute of Scientific and Technical Information of China (English)
ZHOU Ai-Ping; LI Xiao-Qing
2004-01-01
@@ Using the new model of anomalous viscosity, we investigate the magnetic instability in the accretion disks and give the dispersion formula. On the basis of the dispersion relation obtained, it is numerically shown that the instability condition of viscous accretion disk is well consistent with that of the ideal accretion disk, namely there would be magneto-rotational instability in the presence of a vertical weak magnetic field. For a given distance R from the centre of the disk, the growth rate in the anomalous case deviates from the ideal case more greatly when the vertical magnetic field is smaller. The large viscosity limits to the instability. In the two cases, the distributions of growth rate with wave number k approach each other when the magnetic field increases. It greatly represses the effect of viscosity.
Zhou, X.; Ma, L.; Shi, Z.; Fan, W. J.; Evans, R. F. L.; Zheng, Jian-Guo; Chantrell, R. W.; Mangin, S.; Zhang, H. W.; Zhou, S. M.
2015-03-01
In this work, disordered-IrMn3/insulating-Y3Fe5O12 exchange-biased bilayers are studied. The behavior of the net magnetic moment ΔmAFM in the antiferromagnet is directly probed by anomalous and planar Hall effects, and anisotropic magnetoresistance. The ΔmAFM is proved to come from the interfacial uncompensated magnetic moment. We demonstrate that the exchange bias and rotational hysteresis loss are induced by partial rotation and irreversible switching of the ΔmAFM. In the athermal training effect, the state of the ΔmAFM cannot be recovered after one cycle of hysteresis loop. This work highlights the fundamental role of the ΔmAFM in the exchange bias and facilitates the manipulation of antiferromagnetic spintronic devices.
Effect of transition magnetic moments on collective supernova neutrino oscillations
Energy Technology Data Exchange (ETDEWEB)
Gouvêa, André de; Shalgar, Shashank, E-mail: degouvea@northwestern.edu, E-mail: shashank@northwestern.edu [Department of Physics and Astronomy, Northwestern University, Evanston IL 60208-3112 (United States)
2012-10-01
We study the effect of Majorana transition magnetic moments on the flavor evolution of neutrinos and antineutrinos inside the core of Type-II supernova explosions. We find non-trivial collective oscillation effects relating neutrinos and antineutrinos of different flavors, even if one restricts the discussion to Majorana transition electromagnetic moment values that are not much larger than those expected from standard model interactions and nonzero neutrino Majorana masses. This appears to be, to the best of our knowledge, the only potentially observable phenomenon sensitive to such small values of Majorana transition magnetic moments. We briefly comment on the effect of Dirac transition magnetic moments and on the consequences of our results for future observations of the flux of neutrinos of different flavors from a nearby supernova explosion.
Magnetic susceptibility, magnetization, magnetic moment and characterization of Carancas meteorite
Rosales, Domingo
2015-01-01
On September, 15th, 2007, in the community of Carancas (Puno, Peru) a stony meteorite formed a crater explosive type with a mean diameter of 13.5 m. some samples meteorite fragments were collected. The petrologic analysis performed corresponds to a meteorite ordinary chondrite H 4-5. In this paper we have analyzed the magnetic properties of a meteorite fragment with a proton magnetometer. Also in order to have a complete characterization of the Carancas meteorite and its crater, from several papers, articles and reports, we have made a compilation of the most important characteristics and properties of this meteorite.
Quantum Anomalous Hall Effect in Magnetic Insulator Heterostructure
Xu, Gang; Jing WANG; FELSER, CLAUDIA; Qi, Xiao-Liang; Zhang, Shou-Cheng
2014-01-01
Based on ab initio calculations, we predict that a monolayer of Cr-doped (Bi,Sb)2Te3 and GdI2 heterostructure is a quantum anomalous Hall insulator with a non-trivial band gap up to 38 meV. The principle behind our prediction is that the band inversion between two topologically trivial ferromagnetic insulators can result in a non-zero Chern number, which offers a better way to realize the quantum anomalous Hall state without random magnetic doping. In addition, a simple effective model is pre...
Magnetic dipole moment determination by near-field analysis
Eichhorn, W. L.
1972-01-01
A method for determining the magnetic moment of a spacecraft from magnetic field data taken in a limited region of space close to the spacecraft. The spacecraft's magnetic field equations are derived from first principles. With measurements of this field restricted to certain points in space, the near-field equations for the spacecraft are derived. These equations are solved for the dipole moment by a least squares procedure. A method by which one can estimate the magnitude of the error in the calculations is also presented. This technique was thoroughly tested on a computer. The test program is described and evaluated, and partial results are presented.
Determination of the magnetic moment of $^{140}$Pr
Kowalska, M; Kreim, K D; Krieger, A R; Litvinov, Y
We propose to measure the nuclear magnetic moment of the neutron-deficient isotope $^{140}$Pr using collinear laser spectroscopy at the COLLAPS experiment. This nuclide is one of two nuclear systems for which a modulated electron capture decay has been observed in hydrogen-like ions in a storage ring. The firm explanation of the observed phenomenon is still missing but some hypotheses suggest an interaction of the unpaired electron with the surrounding magnetic fields of the ring. In order to verify or discard these hypotheses the magnetic moment of $^{140}$Pr is required since this determines the energy of the 1s hyperfine splitting.
The permanent and induced magnetic dipole moment of the moon
Russell, C. T.; Coleman, P. J., Jr.; Lichtenstein, B. R.; Schubert, G.
1974-01-01
Magnetic field observations with the Apollo 15 subsatellite have been used to deduce the components of both the permanent and induced lunar dipole moments in the orbital plane. The present permanent lunar magnetic dipole moment in the orbital plane is less than 1.3 times ten to the eighteenth power gauss-cu cm. Any uniformly magnetized near surface layer is therefore constrained to have a thickness-magnetization product less than 2.5 emu-cm per g. The induced moment opposes the external field, implying the existence of a substantial lunar ionosphere with a permeability between 0.63 and 0.85. Combining this with recent measures of the ratio of the relative field strength at the ALSEP and Explorer 35 magnetometers indicates that the global lunar permeability relative to the plasma in the geomagnetic tail lobes is between 1.008 and 1.03.
Constraining the neutrino magnetic dipole moment from white dwarf pulsations
Córsico, Alejandro H; Bertolami, Marcelo M Miller; Kepler, S O; García-Berro, Enrique
2014-01-01
Pulsating white dwarf stars can be used as astrophysical laboratories to constrain the properties of weakly interacting particles. Comparing the cooling rates of these stars with the expected values from theoretical models allows us to search for additional sources of cooling due to the emission of axions, neutralinos, or neutrinos with magnetic dipole moment. In this work, we derive an upper bound to the neutrino magnetic dipole moment using an estimate of the rate of period change of the pulsating DB white dwarf star PG 1351+489. By comparing the theoretical rate of change of period expected for this star with the rate of change of period with time of PG 1351+489, we assess the possible existence of additional cooling by neutrinos with magnetic dipole moment. Our models suggest the existence of some additional cooling in this pulsating DB white dwarf, consistent with a non-zero magnetic dipole moment. Our upper limit for the neutrino magnetic dipole moment is somewhat less restrictive than, but still compat...
Magnetic moment of a bound electron
International Nuclear Information System (INIS)
Theoretical predictions underlying determinations of the fine structure constant α and the electron-to-proton mass ratio me/mp are reviewed, with the emphasis on the bound electron magnetic anomaly g-2. The theory of the interaction of hydrogen-like ions with a magnetic field is discussed. The status of efforts aimed at the determination of O(α(Zα)5) and O(α2(Zα)5) corrections to the g factor is presented. The reevaluation of analogous corrections to the Lamb shift and the hyperfine splitting is summarized.
The magnetic moments of the hidden-charm pentaquark states
Wang, Guang-Juan; Ma, Li; Liu, Xiang; Zhu, Shi-Lin
2016-01-01
The magnetic moment of a baryon state is an equally important dynamical observable as its mass, which encodes crucial information of its underlying structure. According to the different color-flavor structure, we have calculated the magnetic moments of the hidden-charm pentaquark states with $J^P={\\frac{1}{2}}^{\\pm}$, ${\\frac{3}{2}}^{\\pm}$, ${\\frac{5}{2}}^{\\pm}$ and ${\\frac{7}{2}}^{+}$ in the molecular model, the diquark-triquark model and the diquark-diquark-antiquark model respectively. Although a good description for the pentaquark mass spectrum and decay patterns has been obtained in all the three models, different color-flavor structures lead to different magnetic moments, which can be used to pin down their inner structures and distinguish various models.
Variational master equation approach to dynamics of magnetic moments
Bogolubov, N. N.; Soldatov, A. V.
2016-07-01
Non-equilibrium properties of a model system comprised of a subsystem of magnetic moments strongly coupled to a selected Bose field mode and weakly coupled to a heat bath made of a plurality of Bose field modes was studied on the basis of non-equilibrium master equation approach combined with the approximating Hamiltonian method. A variational master equation derived within this approach is tractable numerically and can be readily used to derive a set of ordinary differential equations for various relevant physical variables belonging to the subsystem of magnetic moments. Upon further analysis of the thus obtained variational master equation, an influence of the macroscopic filling of the selected Bose field mode at low enough temperatures on the relaxation dynamics of magnetic moments was revealed.
Neutrino emission in neutron matter from magnetic moment interactions
Jaikumar, P; Gale, C; Jaikumar, Prashanth; Gale, Charles
2004-01-01
Neutrino emission drives neutron star cooling for the first several hundreds of years after its birth. Given the low energy ($\\sim$ keV) nature of this process, one expects very few nonstandard particle physics contributions which could affect this rate. Requiring that any new physics contributions involve light degrees of freedom, one of the likely candidates which can affect the cooling process would be a nonzero magnetic moment for the neutrino. To illustrate, we compute the emission rate for neutrino pair bremsstrahlung in neutron-neutron scattering through photon-neutrino magnetic moment coupling. We also present analogous differential rates for neutrino scattering off nucleons and electrons that determine neutrino opacities in supernovae. Employing current upper bounds from collider experiments on the tau magnetic moment, we find that the neutrino emission rate can exceed the rate through neutral current electroweak interaction by a factor two, signalling the importance of new particle physics input to ...
Anomalous Hall Effect in Geometrically Frustrated Magnets
Directory of Open Access Journals (Sweden)
D. Boldrin
2012-01-01
space mechanism based on spin chirality that was originally applied to the pyrochlore Nd2Mo2O7 appears unsatisfactory. Recently, an orbital description based on the Aharonov-Bohm effect has been proposed and applied to both the ferromagnetic pyrochlores Nd2Mo2O7 and Pr2Ir2O7; the first of which features long-ranged magnetic order while the latter is a chiral spin liquid. Two further examples of geometrically frustrated conducting magnets are presented in this paper—the kagome-like Fe3Sn2 and the triangular PdCrO2. These possess very different electronic structures to the 3-dimensional heavy-metal pyrochlores and provide new opportunities to explore the different origins of the AHE. This paper summarises the experimental findings in these materials in an attempt to unite the conflicting theoretical arguments.
Effective particle magnetic moment of multi-core particles
Energy Technology Data Exchange (ETDEWEB)
Ahrentorp, Fredrik; Astalan, Andrea; Blomgren, Jakob; Jonasson, Christian [Acreo Swedish ICT AB, Arvid Hedvalls backe 4, SE-411 33 Göteborg (Sweden); Wetterskog, Erik; Svedlindh, Peter [Department of Engineering Sciences, Uppsala University, Box 534, SE-751 21 Uppsala (Sweden); Lak, Aidin; Ludwig, Frank [Institute of Electrical Measurement and Fundamental Electrical Engineering, TU Braunschweig, D‐38106 Braunschweig Germany (Germany); IJzendoorn, Leo J. van [Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Westphal, Fritz; Grüttner, Cordula [Micromod Partikeltechnologie GmbH, D ‐18119 Rostock (Germany); Gehrke, Nicole [nanoPET Pharma GmbH, D ‐10115 Berlin Germany (Germany); Gustafsson, Stefan; Olsson, Eva [Department of Applied Physics, Chalmers University of Technology, SE-412 96 Göteborg (Sweden); Johansson, Christer, E-mail: christer.johansson@acreo.se [Acreo Swedish ICT AB, Arvid Hedvalls backe 4, SE-411 33 Göteborg (Sweden)
2015-04-15
In this study we investigate the magnetic behavior of magnetic multi-core particles and the differences in the magnetic properties of multi-core and single-core nanoparticles and correlate the results with the nanostructure of the different particles as determined from transmission electron microscopy (TEM). We also investigate how the effective particle magnetic moment is coupled to the individual moments of the single-domain nanocrystals by using different measurement techniques: DC magnetometry, AC susceptometry, dynamic light scattering and TEM. We have studied two magnetic multi-core particle systems – BNF Starch from Micromod with a median particle diameter of 100 nm and FeraSpin R from nanoPET with a median particle diameter of 70 nm – and one single-core particle system – SHP25 from Ocean NanoTech with a median particle core diameter of 25 nm.
Effective particle magnetic moment of multi-core particles
Ahrentorp, Fredrik; Astalan, Andrea; Blomgren, Jakob; Jonasson, Christian; Wetterskog, Erik; Svedlindh, Peter; Lak, Aidin; Ludwig, Frank; van IJzendoorn, Leo J.; Westphal, Fritz; Grüttner, Cordula; Gehrke, Nicole; Gustafsson, Stefan; Olsson, Eva; Johansson, Christer
2015-04-01
In this study we investigate the magnetic behavior of magnetic multi-core particles and the differences in the magnetic properties of multi-core and single-core nanoparticles and correlate the results with the nanostructure of the different particles as determined from transmission electron microscopy (TEM). We also investigate how the effective particle magnetic moment is coupled to the individual moments of the single-domain nanocrystals by using different measurement techniques: DC magnetometry, AC susceptometry, dynamic light scattering and TEM. We have studied two magnetic multi-core particle systems - BNF Starch from Micromod with a median particle diameter of 100 nm and FeraSpin R from nanoPET with a median particle diameter of 70 nm - and one single-core particle system - SHP25 from Ocean NanoTech with a median particle core diameter of 25 nm.
Magnetic dipole moments of the heavy tensor mesons in QCD
Energy Technology Data Exchange (ETDEWEB)
Aliev, T.M. [Middle East Technical University, Physics Department, Ankara (Turkey); Institute of Physics, Baku (Azerbaijan); Barakat, T. [Middle East Technical University, Physics Department, Ankara (Turkey); King Saud University, Physics and Astronomy Department, Riyadh (Saudi Arabia); Savci, M. [Middle East Technical University, Physics Department, Ankara (Turkey)
2015-11-15
The magnetic dipole moments of the D{sub 2}, and D{sub S{sub 2}}, B{sub 2}, and B{sub S{sub 2}} heavy tensor mesons are estimated in framework of the light cone QCD sum rules. It is observed that the magnetic dipole moments for the charged mesons are larger than that of its neutral counterpart. It is found that the SU(3) flavor symmetry violation is about 10 % in both b and c sectors. (orig.)
Noncommutative magnetic moment, fundamental length and lepton size
Adorno, T C; Shabad, A E; 10.1103/PhysRevD.86.027702
2012-01-01
Upper bounds on fundamental length are discussed that follow from the fact that a magnetic moment is inherent in a charged particle in noncommutative (NC) electrodynamics. The strongest result thus obtained for the fundamental lenth is still larger than the estimate of electron or muon size achieved following the Brodsky-Drell and Dehlmet approach to lepton compositeness. This means that NC electrodynamics cannot alone explain the whole existing descrepancy between the theoretical and experimental values of the muon magnetic moment. On the contrary, as measurements and calculations are further improved, the fundamental length estimate based on electron data may go down to match its compositeness radius.
Searches for Magnetic Monopoles and Anomalously Charged Objects with ATLAS
Katre, Akshay; The ATLAS collaboration
2016-01-01
Results of searches for highly ionising particles and particles with anomalously high electric charge produced in proton-proton collisions in the ATLAS detector are presented. Such signatures, encompassing particles with charges from 10 to 60 times the electron charge, involve high levels of ionization in the ATLAS detector and can arise from magnetic monopoles or models involving technicolor, doubly charged Higgs bosons or composite dark matter models.
Wang, Shaojie
2016-07-01
Anomalous current pinch, in addition to the anomalous diffusion due to stochastic magnetic perturbations, is theoretically found, which may qualitatively explain the recent DIII-D experiment on resonant magnetic field perturbation. The anomalous current pinch, which may resolve the long-standing issue of seed current in a fully bootstrapped tokamak, is also discussed for the electrostatic turbulence.
Quantum anomalous Hall effect in magnetic topological insulators
Jing WANG; Lian, Biao; Zhang, Shou-Cheng
2014-01-01
The search for topologically non-trivial states of matter has become an important goal for condensed matter physics. Here, we give a theoretical introduction to the quantum anomalous Hall (QAH) effect based on magnetic topological insulators in two-dimension (2D) and three-dimension (3D). In 2D topological insulators, magnetic order breaks the symmetry between the counter-propagating helical edge states, and as a result, the quantum spin Hall effect can evolve into the QAH effect. In 3D, magn...
Baryon magnetic moments in the effective quark Lagrangian approach
Simonov, YA; Tjon, JA; Weda, J; Simonov, Yu A.
2002-01-01
An effective quark Lagrangian is derived from first principles through bilocal gluon field correlators. It is used to write down equations for baryons, containing both perturbative and nonperturbative fields. As a result one obtains magnetic moments of octet and decuplet baryons without the introduc
Examination of the strangeness contribution to the nucleon magnetic moment
Chen, XS; Timmermans, RGE; Sun, WM; Zong, HS; Wang, F
2004-01-01
We examine the nucleon strangeness magnetic moment mu(s) with a lowest order meson cloud model. We observe that (1) strangeness in the nucleon is a natural requirement of the empirical relation mu(p)/mu(n)similar or equal to-3/2, which favors an SU(3) octet meson cloud instead of merely the SU(2) pi
Octet magnetic Moments and their sum rules in statistical model
Batra, M
2013-01-01
The statistical model is implemented to find the magnetic moments of all octet baryons. The well-known sum rules like GMO and CG sum rules has been checked in order to check the consistency of our approach. The small discrepancy between the results suggests the importance of breaking in SU(3) symmetry.
Gamow-Teller transitions and magnetic moments using various interactions
Garcia, Ricardo
2015-01-01
In a single j-shell calculation we consider the effects of several different interactions on the values of Gamow-Teller (B(GT)'s) and magnetic moments. The interactions used are MBZE, J=0 pairing, J_{max} pairing and half and half.
Tuning the magnetic moments in zigzag graphene nanoribbons
DEFF Research Database (Denmark)
Chen, Jingzhe; Vanin, Marco; Hu, Yibin;
2012-01-01
We report a systematic theoretical investigation of the effects of metal substrates on the local magnetic moments of zigzag graphene nanoribbons (ZGNRs). Representative metal surfaces of Au, Pt, Ni, Cu, Al, Ag, and Pd have been analyzed from atomic first principles. Results show that the local ma...
Neutrino emission in neutron matter from magnetic moment interactions
International Nuclear Information System (INIS)
Neutrino emission drives neutron star cooling for the first several hundreds of years after its birth. Given the low-energy (∼keV) nature of this process, one expects very few nonstandard particle-physics contributions which could affect this rate. Requiring that any new physics contributions involve light degrees of freedom, one of the likely candidates which can affect the cooling process would be a nonzero magnetic moment for the neutrino. To illustrate, we compute the emission rate for neutrino pair bremsstrahlung in neutron-neutron scattering through photon-neutrino magnetic moment coupling. We also present analogous differential rates for neutrino scattering off nucleons and electrons that determine neutrino opacities in supernovae. Employing current upper bounds from collider experiments on the τ magnetic moment, we find that the neutrino emission rate can exceed the rate through neutral current electroweak interaction by a factor 2, signaling the importance of new particle physics input to a standard calculation of relevance to neutron star cooling. However, astrophysical bounds on the neutrino magnetic moment imply smaller effects
Probabilistic naturalness measure for dipole moments due to new physics
アカマ, ケイイチ; ハットリ, タカシ; カツウラ, カズオ /; Keiichi, Akama; Takashi, Hattori; Kazuo, KATSUURA
2006-01-01
We introduce a probabilistic measure of naturalness (naturalness level) to fix naturalness bounds quantitatively. It is applied to the anomalous magnetic moments and the electric dipole moments due to new physics.
Probabilistic Naturalness Measure for Dipole Moments due to New Physics
Akama, Keiichi; Hattori, Takashi; Katsuura, Kazuo
2003-01-01
We introduce a probabilistic measure of naturalness (naturalness level) to fix naturalness bounds quantitatively. It is applied to the anomalous magnetic moments and the electric dipole moments due to new physics.
Gate-dependent orbital magnetic moments in carbon nanotubes
DEFF Research Database (Denmark)
Jespersen, Thomas Sand; Grove-Rasmussen, Kasper; Flensberg, Karsten;
2011-01-01
We investigate how the orbital magnetic moments of electron and hole states in a carbon nanotube quantum dot depend on the number of carriers on the dot. Low temperature transport measurements are carried out in a setup where the device can be rotated in an applied magnetic field, thus enabling...... accurate alignment with the nanotube axis. The field dependence of the level structure is measured by excited state spectroscopy and excellent correspondence with a single-particle calculation is found. In agreement with band structure calculations we find a decrease of the orbital magnetic moment...... with increasing electron or hole occupation of the dot, with a scale given by the band gap of the nanotube....
Nonadiabatic behavior of the magnetic moment of a charged particle in a dipole magnetic field
Murakami, Sadayoshi; Sato, Tetsuya; Hasegawa, Akira
1990-01-01
This paper investigates the dynamic behavior of the magnetic moment of a particle confined in a magnetic dipole field in the presence of a low-frequency electrostatic wave. It is shown that there exist two kinds of resonances (the bounce-E x B drift resonance and the wave-drift resonance) by which the adiabaticity of the magnetic moment is broken. The unstable conditions obtained by theoretical considerations showed good agreement with the numerical results.
Magnetic moments of odd-odd spherical nuclei
Achakovskiy, O I; Saperstein, E E; Tolokonnikov, S V
2013-01-01
Magnetic moments of more than one hundred odd-odd spherical nuclei in ground and excited states are calculated within the self-consistent TFFS based on the EDF method by Fayans {\\it et al}. We limit ourselves to nuclei with a neutron and a proton particle (hole) added to the magic or semimagic core. A simple model of no interaction between the odd nucleons is used. In most the cases we analyzed, a good agreement with the experimental data is obtained. Several cases are considered where this simple model does not work and it is necessary to go beyond. The unknown values of magnetic moments of many unstable odd and odd-odd nuclei are predicted including sixty values for excited odd-odd nuclei.
Anomalous transport model study of chiral magnetic effects in heavy ion collisions
Sun, Yifeng; Ko, Che Ming; Li, Feng
2016-10-01
Using an anomalous transport model for massless quarks and antiquarks, we study the effect of a magnetic field on the elliptic flows of quarks and antiquarks in relativistic heavy ion collisions. With initial conditions from a blast wave model and assuming that the strong magnetic field produced in noncentral heavy ion collisions can last for a sufficiently long time, we obtain an appreciable electric quadrupole moment in the transverse plane of a heavy ion collision. The electric quadrupole moment subsequently leads to a splitting between the elliptic flows of quarks and antiquarks. The slope of the charge asymmetry dependence of the elliptic flow difference between positively and negatively charged particles is positive, which is expected from the chiral magnetic wave formed in the produced QGP and observed in experiments at the BNL Relativistic Heavy Ion Collider, only if the Lorentz force acting on the charged particles is neglected and the quark-antiquark scattering is assumed to be dominated by the chirality changing channel.
Energy Technology Data Exchange (ETDEWEB)
Mogi, M., E-mail: mogi@cmr.t.u-tokyo.ac.jp; Yoshimi, R.; Yasuda, K.; Kozuka, Y. [Department of Applied Physics and Quantum Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656 (Japan); Tsukazaki, A. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); PRESTO, Japan Science and Technology Agency (JST), Chiyoda-ku, Tokyo 102-0075 (Japan); Takahashi, K. S. [RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198 (Japan); Kawasaki, M.; Tokura, Y. [Department of Applied Physics and Quantum Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656 (Japan); RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198 (Japan)
2015-11-02
Quantum anomalous Hall effect (QAHE), which generates dissipation-less edge current without external magnetic field, is observed in magnetic-ion doped topological insulators (TIs) such as Cr- and V-doped (Bi,Sb){sub 2}Te{sub 3}. The QAHE emerges when the Fermi level is inside the magnetically induced gap around the original Dirac point of the TI surface state. Although the size of gap is reported to be about 50 meV, the observable temperature of QAHE has been limited below 300 mK. We attempt magnetic-Cr modulation doping into topological insulator (Bi,Sb){sub 2}Te{sub 3} films to increase the observable temperature of QAHE. By introducing the rich-Cr-doped thin (1 nm) layers at the vicinity of both the surfaces based on non-Cr-doped (Bi,Sb){sub 2}Te{sub 3} films, we have succeeded in observing the QAHE up to 2 K. The improvement in the observable temperature achieved by this modulation-doping appears to be originating from the suppression of the disorder in the surface state interacting with the rich magnetic moments. Such a superlattice designing of the stabilized QAHE may pave a way to dissipation-less electronics based on the higher-temperature and zero magnetic-field quantum conduction.
Quantum anomalous Hall effect in magnetic topological insulators
Wang, Jing; Lian, Biao; Zhang, Shou-Cheng
2015-12-01
The search for topologically non-trivial states of matter has become an important goal for condensed matter physics. Here, we give a theoretical introduction to the quantum anomalous Hall (QAH) effect based on magnetic topological insulators in two-dimensions (2D) and three-dimensions (3D). In 2D topological insulators, magnetic order breaks the symmetry between the counter-propagating helical edge states, and as a result, the quantum spin Hall effect can evolve into the QAH effect. In 3D, magnetic order opens up a gap for the topological surface states, and chiral edge state has been predicted to exist on the magnetic domain walls. We present the phase diagram in thin films of a magnetic topological insulator and review the basic mechanism of ferromagnetic order in magnetically doped topological insulators. We also review the recent experimental observation of the QAH effect. We discuss more recent theoretical work on the coexistence of the helical and chiral edge states, multi-channel chiral edge states, the theory of the plateau transition, and the thickness dependence in the QAH effect.
Magnetic moment of delta baryons with extended sea
International Nuclear Information System (INIS)
In this we have constructed the baryon wave function with suitable quark-gluon Fock states for delta particles. In our study, the sea may be consisting of two gluons or a quark-antiquark pair along with a gluon. In our study, we constrain the sea with spin 0,1,2 and color singlet state for simplicity. We have calculated the magnetic moments for delta particles, after modification in valence quark wave function with due addition of sea component
Nuclear magnetic and electric dipole moments of neon-19
International Nuclear Information System (INIS)
This thesis presents a detailed discussion of a series of experiments designed to measure the magnetic and electric dipole moments of the β-emitting nucleus 19Ne. The 19Ne is generated in the reaction 19F(p,n)19Ne and is polarized by a ''stern-Gerlach'' magnet in a rare gas atomic beams machine. The atoms are stored in a cell for many seconds without depolarizing. The parity violating asymmetry in the β angular distribution is used to monitor the nuclear polarization. The polarized atoms are stored in a cell in a uniform magnetic field. The β-asymmetry is monitored by a pair of β-detectors located on either side of the cell. Transitions between the M/sub J/ = +1/2 and M/sub J/ = -1/2 spin states are induced by an rf field generated by a small Helmholtz coil pair surrounding the cell. Nuclear magnetic resonance lines are observed and the magnetic moment of 19Ne measured to be μ(19Ne) = -1.88542(8)μ/sub N/. A new magnet, cell and detectors were designed to give narrow resonance lines. The equipment is described in detail and several resonance line shapes are discussed. The narrowest resonance line achieved with this system was 0.043 Hz FWHM. This width is primarily due to the 19Ne lifetime. Pulsed NMR lineshapes were also observed. The narrow NMR lines observed in the previous experiment were then used as a probe to look for an electric dipole moment (EDM) in 19Ne. Any shift in the resonance frequency correlated with changes in an externally applied electric field would be evidence for an EDM. The EDM of the 19Ne atom was measured to (7.2 +/- 6.2 X 10-22 e-cm. This experiment and possible improvements are discussed in detail
Strange Quark Magnetic Moment of the Nucleon at Physical Point
Sufian, Raza Sabbir; Alexandru, Andrei; Draper, Terrence; Liu, Keh-Fei; Liang, Jian
2016-01-01
We report a lattice QCD calculation of the strange quark contribution to the proton's magnetic moment and charge radius. This analysis presents the first direct determination of strange electromagnetic form factors including the physical pion mass with chiral fermions. We perform a model-independent extraction of the strange magnetic moment and the strange charge radius from the electromagnetic form factors in the momentum transfer range of $0.051 \\,\\text{GeV}^2 \\lesssim Q^2 \\lesssim 1.31 \\,\\text{GeV}^2 $. The finite lattice spacing and finite volume corrections are included in a global fitting with $17$ valence quark masses on three lattices with different lattice spacings, different volumes, and three sea quark masses including one at the physical pion mass. We obtain the strange magnetic moment $G^s_M(0) = - 0.073(17)(08)\\, \\mu_N$. The 4-sigma precision in statistics is achieved partly due to the low-mode averaging of the quark loop and low-mode substitution of the nucleon source to improve the statistics ...
QCD Sum Rules: Intercrossed Relations for Sigma^0 and Lambda Magnetic Moments
Özpineci, A; Zamiralov, V S
2003-01-01
New relations between QCD Borel sum rules for magnetic moments of Sigma^0 and Lambda hyperons are constructed. It is shown that starting from the sum rule for the Sigma^0 hyperon magnetic moment it is straightforward to obtain the corresponding sum rule for the Lambda hyperon magnetic moment et vice versa.
Magnetic Topological Insulators and Quantum Anomalous Hall Effect
Kou, Xufeng
The engineering of topological surface states is a key to realize applicable devices based on topological insulators (TIs). Among various proposals, introducing magnetic impurities into TIs has been proven to be an effective way to open a surface gap and integrate additional ferromagnetism with the original topological order. In this Dissertation, we study both the intrinsic electrical and magnetic properties of the magnetic TI thin films grown by molecular beam epitaxy. By doping transition element Cr into the host tetradymite-type V-VI semiconductors, we achieve robust ferromagnetic order with a strong perpendicular magnetic anisotropy. With additional top-gating capability, we realize the electric-field-controlled ferromagnetism in the magnetic TI systems, and demonstrate such magneto-electric effects can be effectively manipulated, depending on the interplays between the band topology, magnetic exchange coupling, and structural engineering. Most significantly, we report the observation of quantum anomalous Hall effect (QAHE) in the Cr-doped (BiSb)2Te3 samples where dissipationless chiral edge conduction is realized in the macroscopic millimeter-size devices without the presence of any external magnetic field, and the stability of the quantized Hall conductance of e2/h is well-maintained as the film thickness varies across the 2D hybridization limit. With additional quantum confinement, we discover the metal-to-insulator switching between two opposite QAHE states, and reveal the universal QAHE phase diagram in the thin magnetic TI samples. In addition to the uniform magnetic TIs, we further investigate the TI/Cr-doped TI bilayer structures prepared by the modulation-doped growth method. By controlling the magnetic interaction profile, we observe the Dirac hole-mediated ferromagnetism and develop an effective way to manipulate its strength. Besides, the giant spin-orbit torque in such magnetic TI-based heterostructures enables us to demonstrate the current
The secular variation of pulsar magnetic dipole moments
International Nuclear Information System (INIS)
The time dependences of the inertia tensor and of a dissipative torque caused by the nonleptonic weak interaction have been investigated for a certain class of pulsars with no solid core. Early in the life of the pulsar, the angular velocity vector is predicted to move with respect to fixed body axes in such a way that it becomes perpendicular to the magnetic dipole moment. During this motion, the solid outer shell suffers plastic deformation so that the dipole moment becomes approximately collinear with a principal axis. After 104 or 105 yr, the dissipative torque is negligibly small compared with the electromagnetic torque, the Euler equations are those for a simple rigid body, and alignment of spin and dipole moment occurs. If the dipole moment discussed by Lyne et al. (1975) is interpreted as being equal to the component perpendicular to the spin, its secular decay is a natural property of this model and is not a consequence of field decay through electrical resistivity. (Auth.)
The muon magnetic moment in the ${\\rm{2HDM}}$: complete two-loop result
Cherchiglia, Adriano; Stöckinger, Dominik; Stöckinger-Kim, Hyejung
2016-01-01
We study the ${\\rm{2HDM}}$ contribution to the muon anomalous magnetic moment $a_\\mu$ and present the complete two-loop result, particularly for the bosonic contribution. We focus on the Aligned ${\\rm{2HDM}}$, which has general Yukawa coupling constants and is more general than the type I, II, X, Y models. The result is expressed with physical parameters: three Higgs boson masses, Yukawa couplings, two mixing angles, and one quartic potential parameter. We show that the result can be split into several parts, each of which has a simple parameter dependence, and we document the general behavior. Taking into account constraints on parameters, we find that the full ${\\rm{2HDM}}$ contribution to $a_\\mu$ can accommodate the current experimental value, and the complete two-loop bosonic result contribution can amount to $(2\\cdots 4)\\times 10^{-10}$, more than the future experimental uncertainty.
Deuteron Magnetic Quadrupole Moment From Chiral Effective Field Theory
Liu, C -P; Mereghetti, E; Timmermans, R G E; van Kolck, U
2012-01-01
We calculate the magnetic quadrupole moment (MQM) of the deuteron at leading order in the systematic expansion provided by chiral effective field theory. We take into account parity and time-reversal violation which, at the quark-gluon level, results from the QCD vacuum angle and dimension-six operators that originate from physics beyond the Standard Model. We show that the deuteron MQM can be expressed in terms of five low-energy constants that appear in the parity- and time-reversal-violating nuclear potential and electromagnetic current, four of which also contribute to the electric dipole moments of light nuclei. We conclude that the deuteron MQM has an enhanced sensitivity to the QCD vacuum angle and that its measurement would be complementary to the proposed measurements of light-nuclear EDMs.
Magnetic Moments of Octet Baryons in Hot and Dense Nuclear Matter
Singh, Harpreet; Dahiya, Harleen
2016-01-01
We have calculated the in-medium magnetic moments of octet baryons in the presence of hot and dense symmetric nuclear matter. Effective magnetic moments of baryons have been derived from medium modified quark masses within chiral SU(3) quark mean field model.Further, for better insight of medium modification of baryonic magnetic moments, we have considered the explicit contributions from the valence as well as sea quark effects. These effects have been successful in giving the description of baryonic magnetic moments in vacuum. The magnetic moments of baryons are found to vary significantly as a function of density of nuclear medium.
Screening of Local Magnetic Moment by Electrons of Disordered Graphene
Institute of Scientific and Technical Information of China (English)
SHI Li-Peng; XIONG Shi-Jie
2009-01-01
Based on the Anderson impurity model and self-consistent approach,we investigate the condition for the screening of a local magnetic moment by electrons in graphene and the influence of the moment on electronic properties of the system.The results of numerical calculations carried out on a finite sheet of graphene show that when the Fermi energy is above the single occupancy energy and below the double occupancy energy of the local impurity,a magnetic state is possible.A phase diagram in a parameter space spanned by the Coulomb energy U and the Fermi energy is obtained to distinguish the parameter regions for the magnetic and nonmagnetic states of the impurity.We find that the combined effect of the impurity and finite size effect results in a large charge density near the edges of the finite graphene sheet.The density of states exhibits a peak at the Dirac point which is caused by the appearance of the edge states localized at the zigzag edges of the sheet.
Solar Neutrinos with Magnetic Moment Rates and Global Analysis
Pulido, J
2002-01-01
A statistical analysis of the solar neutrino data is presented assuming the solar neutrino deficit to be resolved by the resonant interaction of the neutrino magnetic moment with the solar magnetic field. Four field profiles are investigated, all exhibiting a rapid increase across the bottom of the convective zone, one of them closely following the requirements from recent solar physics investigations. First a 'rates only' analysis is performed whose best fits appear to be remarkably better than all fits from oscillations. A global analysis then follows with the corresponding best fits of a comparable quality to the LMA one. Despite the fact that the resonant spin flavour precession does not predict any day/night effect, the separate SuperKamiokande day and night data are included in the analysis in order to allow for a direct comparison with oscillation scenarios. Remarkably enough, the best fit for rates and global analysis which is compatible with most astrophysical bounds on the neutrino magnetic moment i...
Large orbital magnetic moment in Pt13 clusters
International Nuclear Information System (INIS)
We present an extensive study of Pt13 clusters embedded in a Na-Y zeolite, by comparing calculations for isolated clusters to experimental data. We perform structural refinements for various geometries involving the isolated clusters and calculate the corresponding x-ray absorption and magnetic circular dichroism spectra, from the joint perspective of pseudopotential plane wave calculations and real space multiple scattering theory. Taking into account the spin–orbit coupling significantly improves the previous scalar relativistic predictions of magnetic properties. The ensemble of embedded Pt13 is found to be dominated by a non-magnetic cuboctahedral geometry. One of the implications is that the ground state of Pt13 clusters in the zeolite environment is different from that of isolated particles. We investigate several isomers that yield a magnetic signature. Furthermore, their abundance was estimated by direct comparison with experiment. We found that one third of the magnetic moment of Pt13 comes from the orbital contribution, in agreement with the experimental value. We therefore provide theoretical proof of the extraordinary orbital magnetization in Pt13 clusters. (paper)
Precise quantization of anomalous Hall effect near zero magnetic field
Energy Technology Data Exchange (ETDEWEB)
Bestwick, A. J. [Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Fox, E. J. [Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Kou, Xufeng [Univ. of California, Los Angeles, CA (United States); Pan, Lei [Univ. of California, Los Angeles, CA (United States); Wang, Kang L. [Univ. of California, Los Angeles, CA (United States); Goldhaber-Gordon, D. [Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
2015-05-04
In this study, we report a nearly ideal quantum anomalous Hall effect in a three-dimensional topological insulator thin film with ferromagnetic doping. Near zero applied magnetic field we measure exact quantization in the Hall resistance to within a part per 10,000 and a longitudinal resistivity under 1 Ω per square, with chiral edge transport explicitly confirmed by nonlocal measurements. Deviations from this behavior are found to be caused by thermally activated carriers, as indicated by an Arrhenius law temperature dependence. Using the deviations as a thermometer, we demonstrate an unexpected magnetocaloric effect and use it to reach near-perfect quantization by cooling the sample below the dilution refrigerator base temperature in a process approximating adiabatic demagnetization refrigeration.
Quark Mass Dependence of Nucleon Magnetic Moment and Charge Radii
Institute of Scientific and Technical Information of China (English)
MA Wei-Xing; ZHOU Li-Juan; GU Yun-Ting; PING Rong-Gang
2005-01-01
Understanding hadron structure within the framework of QCD is an extremely challenging problem. Our purpose here is to explain the model-independent consequences of the approximated chiral symmetry of QCD for two famous results concerning the quark structure of the nucleon. We show that both the apparent success of the constituent quark model in reproducing the ratio of proton to neutron magnetic moments and the apparent success of the Foldy term in reproducing the observed charge radius of the neutron are coincidental. That is, a relatively small change of the current quark mass would spoil both results.
Magnetic moments of odd-odd spherical nuclei
Achakovskiy, O. I.; Kamerdzhiev, S. P.; Saperstein, E. E.; Tolokonnikov, S. V.
2013-01-01
Magnetic moments of more than one hundred odd-odd spherical nuclei in ground and excited states are calculated within the self-consistent TFFS based on the EDF method by Fayans {\\it et al}. We limit ourselves to nuclei with a neutron and a proton particle (hole) added to the magic or semimagic core. A simple model of no interaction between the odd nucleons is used. In most the cases we analyzed, a good agreement with the experimental data is obtained. Several cases are considered where this s...
Rashba Interaction and Local Magnetic Moments in a Graphene-BN Heterostructure Intercalated with Au
O'Farrell, E. C. T.; Tan, J. Y.; Yeo, Y.; Koon, G. K. W.; Ã-zyilmaz, B.; Watanabe, K.; Taniguchi, T.
2016-08-01
We intercalate a van der Waals heterostructure of graphene and hexagonal boron nitride with Au, by encapsulation, and show that the Au at the interface is two dimensional. Charge transfer upon current annealing indicates the redistribution of the Au and induces splitting of the graphene band structure. The effect of an in-plane magnetic field confirms that the splitting is due to spin splitting and that the spin polarization is in the plane, characteristic of a Rashba interaction with a magnitude of approximately 25 meV. Consistent with the presence of an intrinsic interfacial electric field we show that the splitting can be enhanced by an applied displacement field in dual gated samples. A giant negative magnetoresistance, up to 75%, and a field induced anomalous Hall effect at magnetic fields <1 T are observed. These demonstrate that the hybridized Au has a magnetic moment and suggests the proximity to the formation of a collective magnetic phase. These effects persist close to room temperature.
Magnetic Moment Fields in Dense Relativistic Plasma Interacting with Laser Radiations
Directory of Open Access Journals (Sweden)
B.Ghosh1* , S.N.Paul 1 , S.Bannerjee2 and C.Das3
2013-04-01
Full Text Available Theory of the generation of magnetic moment field from resonant interaction of three high frequency electromagnetic waves in un-magnetized dense electron plasma is developed including the relativistic change of electron mass. It is shown that the inclusion of relativistic effect enhances the magnetic moment field. For high intensity laser beams this moment field may be of the order of a few mega gauss. Such a high magnetic field can considerably affect the transport of electrons in fusion plasma
Evidence For Intrinsic Magnetic Moments in Black Hole Candidates
Robertson, S L; Robertson, Stanley L.; Leiter, Darryl J.
2002-01-01
We show that the power law part of the quiescent x-ray emissions of neutron stars in low mass x-ray binaries is magnetospheric in origin. It can be very accurately calculated from rates of spin and the $\\sim 10^{3 - 4}$ times brighter luminosity at the transition to the hard spectral state. We establish that the spectral state transition for neutron stars is a magnetospheric propeller effect. We test the hypothesis that the similar spectral state switches and quiescent power law emissions of the black hole candidates might be magnetospheric effects. In the process we derive proposed magnetic moments and rates of spin for them and accurately predict their quiescent luminosities. We discuss other tests of the hypothesis and consider some attractive aspects of a unified magnetospheric model for low mass x-ray binaries. We also consider some of the changes that would be needed for strong-field gravity theories to accomodate intrinsic magnetic moments in collapsed objects.
Shell structure of potassium isotopes deduced from their magnetic moments
Papuga, J; Kreim, K; Barbieri, C; Blaum, K; De Rydt, M; Duguet, T; Garcia Ruiz, R F; Heylen, H; Kowalska, M; Neugart, R; Neyens, G; Nortershauser, W; Rajabali, M M; Sanchez, R; Smirnova, N; Soma, V; Yordanov, D T
2014-01-01
$\\textbf{Background:}$ Ground-state spins and magnetic moments are sensitive to the nuclear wave function, thus they are powerful probes to study the nuclear structure of isotopes far from stability. \\\\ \\\\ $\\textbf{Purpose:}$ Extend our knowledge about the evolution of the $1/2^+$ and $3/2^+$ states for K isotopes beyond the $N = 28$ shell gap. \\\\ \\\\ $\\textbf{Method:}$ High-resolution collinear laser spectroscopy on bunched atomic beams. \\\\ \\\\ $\\textbf{Results:}$ From measured hyperfine structure spectra of K isotopes, nuclear spins and magnetic moments of the ground states were obtained for isotopes from $N = 19$ up to $N = 32$. In order to draw conclusions about the composition of the wave functions and the occupation of the levels, the experimental data were compared to shell-model calculations using SDPF-NR and SDPF-U effective interactions. In addition, a detailed discussion about the evolution of the gap between proton $1d_{3/2}$ and $2s_{1/2}$ in the shell model and $\\textit{ab initio}$ framework is al...
Anomalous Nernst Effect of Perpendicularly Magnetic Anisotropy TbFeCo Thin Films
Ando, Ryo; Komine, Takashi; Hasegawa, Yasuhiro
2016-07-01
In this study, we investigated anomalous Nernst effect (ANE) of perpendicularly magnetized TbFeCo thin films with various Tb content, and especially studied the relation between ANE and anomalous Hall effect. As a result, the hysteresis of anomalous Nernst coefficient showed the same behavior as that of anomalous Hall resistivity, and the sign of anomalous Nernst coefficient was consistent with that of anomalous Hall voltage in any Tb content, whereas the Seebeck coefficient and the resistivity were almost constant even if the applied magnetic field was varied. Taking into account of thermoelectric coefficient tensor, it was revealed that the off-diagonal thermopower corresponding to the ANE in TbFeCo thin films is the product of Hall angle and Seebeck coefficient.
Magnetic moments in a gadolinium iron garnet studied by soft-X-ray magnetic circular dichroism
Rudolf, P.; Sette, F.; Tjeng, L.H.; Meigs, G.; Chen, C.T.
1992-01-01
The magnetic moments of Gd and Fe in gadolinium iron garnet (Gd3Fe5O12) were probed at 77 and 300 K by soft-X-ray magnetic circular dichroism (SXMCD) measurements at the GdMa4,5 and at the FeL2,3 absorption edges. The SXMCD signal at each edge allows one to independently determine the magnetic order
The Gravitational Effects of a Celestial Body with Magnetic Charge and Moment
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The gravitational effects (precession of charge-less particles and deflection of light) in the gravitational field of a celestial body with magnetic charge and moment (CM)are investigated. We found that the magnetic charge always weakens the pure Schwarzschild effects, while the magnetic dipole moment deforms the effects in a more complicated way.
On the origin of the giant magnetic moment of the Al-Mn quasicrystals
Directory of Open Access Journals (Sweden)
Bocharov P.V.
2011-05-01
Full Text Available Ab initio calculations of magnetic moments for icosahedral clusters contained in crystal structures Al10Mn3, Al5Co2, Al17Mn4 (Al13Cr4Si4-type fulfilled in the framework of Density Functional Theory. The AlMn cluster having the trigonal D3h symmetry with the triangle of Mn ions in the interior has the moment being equal to three magnetic moments of a single manganese ion (4.4 μB, the moment of the tetrahedral Td cluster with the Mn tetrahedron in the interior is equal approximately to twelve magnetic moments of the single manganese ion (15.5 μB. The magnetic moment of icosahedral Al-Co clusters having the same configuration is equal to zero. The magnetic moments of the rod assembled from the icosahedral clusters with the sequence Td D3h - Td was found to be 20.5 μB. This value permits to explain the giant magnetic moment of icosahedral and decagonal Al-Mn quasicrystals and gives the indirect evidence to the hierarchical model of the quasicrystals structure proposed by the authors recently. An arrangement of magnetic moment carriers in the interior of the aluminum shell of icosahedral clusters permits to suggest the interaction between contacting manganese ions as the main origin of the giant magnetic moment of the Al-Mn quasicrystals.
Highly Accurate Measurement of the Electron Orbital Magnetic Moment
Awobode, A M
2015-01-01
We propose to accurately determine the orbital magnetic moment of the electron by measuring, in a Magneto-Optical or Ion trap, the ratio of the Lande g-factors in two atomic states. From the measurement of (gJ1/gJ2), the quantity A, which depends on the corrections to the electron g-factors can be extracted, if the states are LS coupled. Given that highly accurate values of the correction to the spin g-factor are currently available, accurate values of the correction to the orbital g-factor may also be determined. At present, (-1.8 +/- 0.4) x 10-4 has been determined as a correction to the electron orbital g-factor, by using earlier measurements of the ratio gJ1/gJ2, made on the Indium 2P1/2 and 2P3/2 states.
Magnetic moments and hyperfine fields at Fe in 3d-transition metals
International Nuclear Information System (INIS)
The magnetic moments and hyperfine fields at Fe sites in 3d-transition metals are calculated using the first principle discrete variational method in local density approximation. Although a large positive moment is retained at each Fe site, the hyperfine fields varied from large negative to large positive values. It is concluded that the absence of Moessbauer magnetic splitting does not necessarily imply the absence of local magnetic moments. (orig.)
Influence of External Magnetic Field on Anomalous Skin Effects in Inductively Coupled Plasmas
Institute of Scientific and Technical Information of China (English)
MAO Ming; WANG You-Nian
2004-01-01
@@ Using a one-dimensional slab model, we study the influence of the external static magnetic field on the anomalous skin effects in the inductively coupled plasma. The rf electromagnetic field in the plasma is determined by solving the linearized Boltzmann equation incorporating with the Maxwell equations. The numerical results show that,due to the existence of the external magnetic field, the anomalous skin effects are greatly enhanced and the number of regions with negative absorption is decreased.
Venkateswarlu, B.; Midhunlal, P. V.; Babu, P. D.; Kumar, N. Harish
2016-06-01
The half-metallic Heusler alloy Co2TiGe has a ferromagnetic ground state with a low magnetic moment (2 μB). It is free of atomic antisite disorder but has low Curie temperature (~390 K). In contrast the other cobalt based Heusler alloy Co2FeGe has high Curie temperature (~980 K) and high magnetic moment (5.6 μB) while exhibiting antisite disorder and lack of half-metallicity. Hence it is of interest to investigate the magnetic and transport properties of solid solutions of these two materials with contrasting characteristics. We report the structural, magnetic and electronic transport properties of quaternary Co2Ti1-x FexGe (x=0.2, 0.4, 0.6, 0.8) Heusler alloys. The alloys crystallize in L21 structure but with antisite disorder. The magnetization measurements revealed that the alloys were of soft ferromagnetic type with high Curie temperatures. Deviation from Slater-Pauling behavior and drastic change in electronic transport properties with some anomalous features were observed.The complex electronic transport properties have been explained using different scattering mechanisms.
Dias, F. T.; Vieira, V. N.; Garcia, E. L.; Wolff-Fabris, F.; Kampert, E.; Gouvêa, C. P.; Schaf, J.; Obradors, X.; Puig, T.; Roa, J. J.
2016-10-01
We have studied the functional behavior of the field-cooled (FC) magnetic relaxation observed in melt-textured YBa2Cu3O7-δ (Y123) samples with 30 wt% of Y2Ba1Cu1O5 (Y211) phase, in order to investigate anomalous paramagnetic moments observed during the experiments. FC magnetic relaxation experiments were performed under controlled conditions, such as cooling rate and temperature. Magnetic fields up to 5T were applied parallel to the ab plane and along the c-axis. Our results are associated with the paramagnetic Meissner effect (PME), characterized by positive moments during FC experiments, and related to the magnetic flux compression into the samples. After different attempts our experimental data could be adequately fitted by an exponential decay function with different relaxation times. We discuss our results suggesting the existence of different and preferential flux dynamics governing the anomalous FC paramagnetic relaxation in different time intervals. This work is one of the first attempts to interpret this controversial effect in a simple analysis of the pinning mechanisms and flux dynamics acting during the time evolution of the magnetic moment. However, the results may be useful to develop models to explain this interesting and still misunderstood feature of the paramagnetic Meissner effect.
Magnetic Moments of Chromium-Doped Gold Clusters: The Anderson Impurity Model in Finite Systems
Hirsch, K; Langenberg, A; Niemeyer, M; Langbehn, B; Möller, T; Terasaki, A; Issendorff, B v; Lau, J T
2013-01-01
The magnetic moment of a single impurity atom in a finite free electron gas is studied in a combined x-ray magnetic circular dichroism spectroscopy and density functional theory study of size-selected free chromium-doped gold clusters. The observed size-dependence of the local magnetic moment can essentially be understood in terms of the Anderson impurity model. Electronic shell closure in the host metal minimizes the interaction of localized impurity states with the confined free electron gas and preserves the full magnetic moment of $\\unit[5]{\\mu_B}$ in $\\mathrm{CrAu}_{2}^{+}$ and $\\mathrm{CrAu}_{6}^{+}$ clusters. Even for open-shell species, large local moments are observed that scale with the energy gap of the gold cluster. This indicates that an energy gap in the free electron gas generally stabilizes the local magnetic moment of the impurity.
Thickness Dependence of the Quantum Anomalous Hall Effect in Magnetic Topological Insulator Films.
Feng, Xiao; Feng, Yang; Wang, Jing; Ou, Yunbo; Hao, Zhenqi; Liu, Chang; Zhang, Zuocheng; Zhang, Liguo; Lin, Chaojing; Liao, Jian; Li, Yongqing; Wang, Li-Li; Ji, Shuai-Hua; Chen, Xi; Ma, Xucun; Zhang, Shou-Cheng; Wang, Yayu; He, Ke; Xue, Qi-Kun
2016-08-01
The evolution of the quantum anomalous Hall effect with the thickness of Cr-doped (Bi,Sb)2 Te3 magnetic topological insulator films is studied, revealing how the effect is caused by the interplay of the surface states, band-bending, and ferromagnetic exchange energy. Homogeneity in ferromagnetism is found to be the key to high-temperature quantum anomalous Hall material. PMID:27166762
Carrier-independent ferromagnetism and giant anomalous Hall effect in magnetic topological insulator
Chang, Cui-Zu; Zhang, Jin-song; Liu, Min-Hao; Zhang, Zuo-Cheng; Feng, Xiao; Li, Kang; Wang, Li-Li; Chen, Xi; Dai, Xi; Fang, Zhong; Qi, Xiao-Liang; Zhang, Shou-Cheng; Wang, Yayu; He, Ke; Ma, Xu-Cun
2011-01-01
Breaking the time-reversal symmetry of a topological insulator (TI) by ferromagnetism can induce exotic magnetoelectric phenomena such as quantized anomalous Hall (QAH) effect. Experimental observation of QAH effect in a magnetically doped TI requires ferromagnetism not relying on the charge carriers. We have realized the ferromagnetism independent of both polarity and density of carriers in Cr-doped BixSb2-xTe3 thin films grown by molecular beam epitaxy. Meanwhile, the anomalous Hall effect ...
On the origin of the giant magnetic moment of the Al-Mn quasicrystals
Bocharov P.V.; Bazhanov D.A.; Kraposhin V.S.
2011-01-01
Ab initio calculations of magnetic moments for icosahedral clusters contained in crystal structures Al10Mn3, Al5Co2, Al17Mn4 (Al13Cr4Si4-type) fulfilled in the framework of Density Functional Theory. The AlMn cluster having the trigonal D3h symmetry with the triangle of Mn ions in the interior has the moment being equal to three magnetic moments of a single manganese ion (4.4 μB), the moment of the tetrahedral Td cluster with the Mn tetrahedron in the interior is equal approximately t...
Magnetic and Electric Dipole Moments of the \\(H\\ ^3\\Delta_1\\) State in ThO
DeMille, David; Spaun, Benjamin Norman; Gurevich, Yulia Vsevolodovna; Hutzler, Nicholas Richard; Kirilov, Emil; Doyle, John M.; Gabrielse, Gerald; Vutha, Amar
2011-01-01
The metastable \\(H\\ ^3\\Delta_1\\) state in the thorium monoxide (ThO) molecule is highly sensitive to the presence of a CP-violating permanent electric dipole moment of the electron (eEDM). The magnetic dipole moment \\(\\mu_H\\) and the molecule-fixed electric dipole moment \\(D_H\\) of this state are measured in preparation for a search for the eEDM. The small magnetic moment \\(\\mu_H = 8.5(5) \\times 10^{-3}\\ \\mu_B\\) displays the predicted cancellation of spin and orbital contributions in a \\(^3\\D...
Gyrotropic Magnetic Effect and the Magnetic Moment on the Fermi Surface.
Zhong, Shudan; Moore, Joel E; Souza, Ivo
2016-02-19
The current density j^{B} induced in a clean metal by a slowly-varying magnetic field B is formulated as the low-frequency limit of natural optical activity, or natural gyrotropy. Working with a multiband Pauli Hamiltonian, we obtain from the Kubo formula a simple expression for α_{ij}^{GME}=j_{i}^{B}/B_{j} in terms of the intrinsic magnetic moment (orbital plus spin) of the Bloch electrons on the Fermi surface. An alternate semiclassical derivation provides an intuitive picture of the effect, and takes into account the influence of scattering processes in dirty metals. This "gyrotropic magnetic effect" is fundamentally different from the chiral magnetic effect driven by the chiral anomaly and governed by the Berry curvature on the Fermi surface, and the two effects are compared for a minimal model of a Weyl semimetal. Like the Berry curvature, the intrinsic magnetic moment should be regarded as a basic ingredient in the Fermi-liquid description of transport in broken-symmetry metals. PMID:26943554
The spin periods and magnetic moments of white dwarfs in magnetic cataclysmic variables
Norton, A; Somerscales, R V
2004-01-01
We have used a model of magnetic accretion to investigate the rotational equilibria of magnetic cataclysmic variables (mCVs). The results of our numerical simulations demonstrate that there is a range of parameter space in the P_spin / P_orb versus mu_1 plane at which rotational equilibrium occurs. This has allowed us to calculate the theoretical histogram describing the distribution of magnetic CVs as a function of P_spin / P_orb. We show that this agrees with the observed distribution assuming that the number of systems as a function of white dwarf magnetic moment is distributed approximately according to N(mu_1) d mu_1 proportional to 1/mu_1 d mu_1. The rotational equilibria also allow us to infer approximate values for the magnetic moments of all known intermediate polars. We predict that intermediate polars with mu_1 > 5 x 10^33 G cm^3 and P_orb > 3h will evolve into polars, whilst those with mu_1 3h will either evolve into low field strength polars which are (presumably) unobservable, and possibly EUV ...
`Anomalous' magnetic fabrics of dikes in the stable single domain/superparamagnetic threshold
Soriano, Carles; Beamud, Elisabet; Garcés, Miguel; Ort, Michael H.
2016-02-01
`Anomalous' magnetic fabrics in dikes that appear to indicate flow into the wall confound many workers. Here, we present extensive magnetic data on five dikes from Tenerife, Canary Islands, and use these to interpret the causes of the anomalous fabrics. Comparison of the anisotropy of magnetic susceptibility (AMS) and anhysteretic magnetization (AARM) results show that, in some cases, the anomalous fabrics are caused by single-domain grains, which produce AMS fabrics perpendicular to the grain elongation, whereas AARM fabrics are parallel. To check this, hysteresis experiments were used to characterize the domain state. These show most are mixtures of pseudo-single-domain or single-domain plus multi-domain particles, but many have wasp-waisted hysteresis loops, likely indicating mixed populations of stable single-domain and superparamagnetic grains. First-order reversal curves were used to better characterize this and show mixtures of stable single-domain and superparamagnetic grains dominate the magnetic signal. Magnetic particles at the stable single-domain/superparamagnetic threshold are unstable at timespans relevant to the analytical techniques, so they produce complicated results. This suggests that anomalous AMS fabrics in dikes cannot simply be attributed to elongated stable single-domain particles and that mixtures of the different grain types can produce hybrid fabrics, in which the fabrics are neither perpendicular or parallel to the dike plane, that are difficult to interpret without extensive magnetic analysis.
Probing the magnetic moment of FePt micromagnets prepared by focused ion beam milling
Energy Technology Data Exchange (ETDEWEB)
Overweg, H. C.; Haan, A. M. J. den; Eerkens, H. J.; Bossoni, L.; Oosterkamp, T. H., E-mail: oosterkamp@physics.leidenuniv.nl [Huygens-Kamerlingh Onnes Laboratory, Leiden University, Niels Bohrweg 2, 2333CA Leiden (Netherlands); Alkemade, P. F. A. [Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands); La Rooij, A. L.; Spreeuw, R. J. C. [Van der Waals-Zeeman Institute, University of Amsterdam, Science Park 904, 1090 GL Amsterdam (Netherlands)
2015-08-17
We investigate the degradation of the magnetic moment of a 300 nm thick FePt film induced by Focused Ion Beam (FIB) milling. A 1 μm × 8 μm rod is milled out of a film by a FIB process and is attached to a cantilever by electron beam induced deposition. Its magnetic moment is determined by frequency-shift cantilever magnetometry. We find that the magnetic moment of the rod is μ = 1.1 ± 0.1 × 10{sup −12} Am{sup 2}, which implies that 70% of the magnetic moment is preserved during the FIB milling process. This result has important implications for atom trapping and magnetic resonance force microscopy, which are addressed in this paper.
Tunability of Size and Magnetic Moment of Iron Oxide Nanoparticles Synthesized by Forced Hydrolysis
Directory of Open Access Journals (Sweden)
Ben Sutens
2016-07-01
Full Text Available To utilize iron oxide nanoparticles in biomedical applications, a sufficient magnetic moment is crucial. Since this magnetic moment is directly proportional to the size of the superparamagnetic nanoparticles, synthesis methods of superparamagnetic iron oxide nanoparticles with tunable size are desirable. However, most existing protocols are plagued by several drawbacks. Presented here is a one-pot synthesis method resulting in monodisperse superparamagnetic iron oxide nanoparticles with a controllable size and magnetic moment using cost-effective reagents. The obtained nanoparticles were thoroughly characterized by transmission electron microscopy (TEM, X-ray diffraction (XRD and Fourier transform infrared (FT-IR measurements. Furthermore, the influence of the size on the magnetic moment of the nanoparticles is analyzed by superconducting quantum interference device (SQUID magnetometry. To emphasize the potential use in biomedical applications, magnetic heating experiments were performed.
Hypernuclear Magnetic Moments and ∧-N Interaction in 17∧O
Institute of Scientific and Technical Information of China (English)
L(U) Hong-Feng
2007-01-01
Hypernuclear magnetic moment and ∧-N interaction in 17∧O has been studied within relativistic mean field theory.Without core polarization, the relativistic results are found to fit the Schmidt value well and not be sensitive to ∧-N interaction. The relativistic magnetic moment is enhanced with nearly equal contributions of the relativistic and free masses. When ∧ hyperon occupies the l = 0 or l = 1 orbit, the effect of ∧-N interaction on the magnetic moment of valence proton is different.
Majorana Neutrino Magnetic Moment and Neutrino Decoupling in Big Bang Nucleosynthesis
Vassh, N; Balantekin, A B; Fuller, G M
2015-01-01
We examine the physics of the early universe when neutrinos (electron neutrino, muon neutrino, tau neutrino) possess transition magnetic moments. These extra couplings beyond the usual weak interaction couplings alter the way neutrinos decouple from the plasma of electrons/positrons and photons. We calculate how transition magnetic moment couplings modify neutrino decoupling temperatures, and then use a full weak, strong, and electromagnetic reaction network to compute corresponding changes in Big Bang Nucleosynthesis abundance yields. We find that light element observational constraints and other cosmological constraints may allow probes of neutrino transition magnetic moments which are not directly available in the laboratory.
One-pion exchange current corrections for nuclear magnetic moments in relativistic mean field theory
Li, Jian; Meng, J; Arima, A
2010-01-01
The one-pion exchange current corrections to isoscalar and isovector magnetic moments of double-closed shell nuclei plus and minus one nucleon with $A=15,17,39$ and 41 have been studied in the relativistic mean field (RMF) theory and compared with previous relativistic and non-relativistic results. It has been found that the one-pion exchange current gives a negligible contribution to the isoscalar magnetic moments but a significant correction to the isovector ones. However, the one-pion exchange current doesn't improve the description of nuclear isovector magnetic moments for the concerned nuclei.
Ultra-high Sensitivity Moment Magnetometry of Geological Samples Using Magnetic Microscopy
Lima, Eduardo A
2016-01-01
Paleomagnetically useful information is expected to be recorded by samples with moments up to three orders of magnitude below the detection limit of standard superconducting rock magnetometers. Such samples are now detectable using recently developed magnetic microscopes, which map the magnetic fields above room-temperature samples with unprecedented spatial resolutions and field sensitivities. However, realizing this potential requires the development of techniques for retrieving sample moments from magnetic microscopy data. With this goal, we developed a technique for uniquely obtaining the net magnetic moment of geological samples from magnetic microscopy maps of unresolved or nearly unresolved magnetization. This technique is particularly powerful for analyzing small, weakly magnetized samples such as meteoritic chondrules and terrestrial silicate crystals like zircons. We validated this technique by applying it to field maps generated from synthetic sources and also to field maps measured using a superco...
Field Induced Magnetic Moments in a Metastable Iron-Mercury Alloy
DEFF Research Database (Denmark)
Pedersen, M.S.; Mørup, Steen; Linderoth, Søren;
1996-01-01
The magnetic properties of a metastable iron-mercury alloy have been investigated in the temperature range from 5 to 200 K by Mossbauer spectroscopy and magnetization measurements. At low temperature the magnetic moment per iron atom is larger than af alpha-Fe. The effective spontaneous magnetic ....... It was found that the field-induced increase of the magnetic moment in the metastable iron-mecury alloy was about 0.06 Bohr magnetons per iron atom in the temperature range from 5 to 200 K for a field change from 6 to 12 T....
Re-creating Gauss's method for non-electrical absolute measurements of magnetic fields and moments
Van Baak, D. A.
2013-10-01
In 1832, Gauss made the first absolute measurements of magnetic fields and of magnetic moments in experiments that are straightforward and instructive to replicate. We show, using rare-earth permanent magnets and a variation of Gauss's technique, that the horizontal component of the ambient geomagnetic field, as well as the size of the magnetic moments of such magnets, can be found. The method shows the connection between the SI and cgs emu unit systems for these quantities and permits an absolute realization of the Ampere with considerable precision.
Planar Hall ring sensor for ultra-low magnetic moment sensing
DEFF Research Database (Denmark)
Hung, Tran Quang; Terki, Ferial; Kamara, Souleymanne;
2015-01-01
The field sensitivity of a planar Hall effect (PHE) micro-ring type biosensor has been investigated as a function of magnetizing angle of the sensor material, for the sensing of low magnetic moment superparamagnetic labels. The field sensitivity is maximal at a magnetizing angle of α = 20......°. At this optimized magnetizing angle, the field sensitivity of a PHE sensor is about 3.6 times higher than that measured at the conventional configuration, α = 90°. This optimization enables the PHE-ring sensor to detect superparamagnetic biolabels with ultra-low magnetic moments down to 4 × 10-13 emu....
Planar Hall ring sensor for ultra-low magnetic moment sensing
Hung, Tran Quang; Terki, Ferial; Kamara, Souleymanne; Kim, Kunwoo; Charar, Salam; Kim, CheolGi
2015-04-01
The field sensitivity of a planar Hall effect (PHE) micro-ring type biosensor has been investigated as a function of magnetizing angle of the sensor material, for the sensing of low magnetic moment superparamagnetic labels. The field sensitivity is maximal at a magnetizing angle of α = 20°. At this optimized magnetizing angle, the field sensitivity of a PHE sensor is about 3.6 times higher than that measured at the conventional configuration, α = 90°. This optimization enables the PHE-ring sensor to detect superparamagnetic biolabels with ultra-low magnetic moments down to 4 × 10-13 emu.
X-ray detection of transient magnetic moments induced by a spin current in Cu
Energy Technology Data Exchange (ETDEWEB)
Kukreja, R. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); Bonetti, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); Chen, Z. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); Backes, D. [New York Univ. (NYU), New York, NY (United States); Acremann, Y. [ETH Zurich, Zurich (Switzerland); Katine, J. [HGST, a Western Digital Company, San Jose, CA (United States); Kent, A. D. [New York Univ. (NYU), New York, NY (United States); Durr, H. A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Ohldag, H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stohr, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States)
2015-08-24
We have used a MHz lock-in x-ray spectromicroscopy technique to directly detect changes in magnetic moment of Cu due to spin injection from an adjacent Co layer. The elemental and chemical specificity of x rays allows us to distinguish two spin current induced effects. We detect the creation of transient magnetic moments of 3×10^{–5}_{μB} on Cu atoms within the bulk of the 28 nm thick Cu film due to spin accumulation. The moment value is compared to predictions by Mott’s two current model. We also observe that the hybridization induced existing magnetic moments at the Cu interface atoms are transiently increased by about 10% or 4×10^{–3}_{μB} per atom. As a result, this reveals the dominance of spin-torque alignment over Joule heat induced disorder of the interfacial Cu moments during current flow.
Energy Technology Data Exchange (ETDEWEB)
Bluemlein, Johannes; Klein, Sebastian [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Kauers, Manuel; Schneider, Carsten [Johannes Kepler Univ., Linz (Austria). Research Inst. for Symbolic Computation
2009-02-15
Single scale quantities, as anomalous dimensions and hard scattering cross sections, in renormalizable Quantum Field Theories are found to obey difference equations of finite order in Mellin space. It is often easier to calculate fixed moments for these quantities compared to a direct attempt to derive them in terms of harmonic sums and their generalizations involving the Mellin parameter N. Starting from a sufficiently large number of given moments, we establish linear recurrence relations of lowest possible order with polynomial coefficients of usually high degree. Then these recurrence equations are solved in terms of d'Alembertian solutions where the involved nested sums are represented in optimal nested depth. Given this representation, it is then an easy task to express the result in terms of harmonic sums. In this process we compactify the result such that no algebraic relations occur among the sums involved. We demonstrate the method for the QCD unpolarized anomalous dimensions and massless Wilson coefficients to 3-loop order treating the contributions for individual color coefficients. For the most complicated subproblem 5114 moments were needed in order to produce a recurrence of order 35 whose coefficients have degrees up to 938. About four months of CPU time were needed to establish and solve the recurrences for the anomalous dimensions and Wilson coefficients on a 2 GHz machine requiring less than 10 GB of memory. No algorithm is known yet to provide such a high number of moments for 3-loop quantities. Yet the method presented shows that it is possible to establish and solve recurrences of rather large order and degree, occurring in physics problems, uniquely, fast and reliably with computer algebra. (orig.)
Mein, P.; Uitenbroek, H.; Mein, N.; Bommier, V.; Faurobert, M.
2016-06-01
Context. In the case of unresolved solar structures or stray light contamination, inversion techniques using four Stokes parameters of Zeeman profiles cannot disentangle the combined contributions of magnetic and nonmagnetic areas to the observed Stokes I. Aims: In the framework of a two-component model atmosphere with filling factor f, we propose an inversion method restricting input data to Q , U, and V profiles, thus overcoming ambiguities from stray light and spatial mixing. Methods: The V-moments inversion (VMI) method uses shifts SV derived from moments of V-profiles and integrals of Q2, U2, and V2 to determine the strength B and inclination ψ of a magnetic field vector through least-squares polynomial fits and with very few iterations. Moment calculations are optimized to reduce data noise effects. To specify the model atmosphere of the magnetic component, an additional parameter δ, deduced from the shape of V-profiles, is used to interpolate between expansions corresponding to two basic models. Results: We perform inversions of HINODE SOT/SP data for inclination ranges 0 VMI inversion are compared with results from the inversion codes UNNOFIT and MERLIN. Conclusions: The VMI inversion method is insensitive to the dependence of Stokes I profiles on the thermodynamic structure in nonmagnetic areas. In the range of Bf products larger than 200 G, mean field strengths exceed 1000 G and there is not a very significant departure from the UNNOFIT results because of differences between magnetic and nonmagnetic model atmospheres. Further improvements might include additional parameters deduced from the shape of Stokes V profiles and from large sets of 3D-MHD simulations, especially for unresolved magnetic flux tubes.
Enhanced Magnetic Moment of the Iron in a Metastable Iron-Mercury Alloy
DEFF Research Database (Denmark)
Pedersen, Michael Stanley; Mørup, Steen; Linderoth, S.;
1996-01-01
Ultrafine magnetic particles consisting of a metastable iron-mercury alloy have been investigated in the range 15 K to 200 K by Mossbauer spectroscopy and magnetization measurements. The effective magnetic moment of iron in the iron mercury alloy is found to be enhanced above the value for alpha-...
Contribution to the neutrino magnetic moment coming from 2HDM in presence of magnetic fields
Tarazona, Carlos G; Moralesa, John; Castillo, Andrés
2016-01-01
The confirmation of the neutrino mass by oscillation phenomena converts the study of the magnetic dipole moment (MDM) of the neutrino, in vacuum and regions where existing external magnetic fields, a topic of particular interest from the theoretical point of view. The MDM has an implicit relation with neutrino masses, and this is a possible benchmark from new physics in the solution of open questions in neutrino physics. Besides we know that this kind of phenomena has significant consequences on cosmology and astrophysics, e.g., under the influence of combined effects of neutrinos in the compact objects formation and evolution of primordials magnetic fields. We calculate and analyze such effects introducing charged Higgs bosons based on the parameter space of several 2HDMs with and without flavor conservation in neutral currents.
Low magnetic moment PIN diodes for high field MRI surface coils.
Voskoboynik, Pavel; Joos, Ronald D; Doherty, W E; Goldfarb, Ron B
2006-12-01
Positive-intrinsic-negative (PIN) silicon diodes are commonly used in magnetic resonance imaging (MRI) coils to perform active or passive blocking and detuning, or to disable circuit functions. However, diode packages with large magnetic moments are known to cause image artifacts in high field MRI systems. In this study, diode packages with low magnetic moment were designed by compensating components of ferromagnetic nickel and paramagnetic tungsten with diamagnetic silver. The new diodes have an initial positive susceptibility up to fields of 1 T and a negative susceptibility from 1 to 7 T. Their magnetic moments are one to two orders of magnitude smaller than those of standard diodes; moments as small as 20 nJ/T at 7 T were achieved. PMID:17278801
Core Polarization and Tensor Coupling Effects on Magnetic Moments of Hypernuclei
Institute of Scientific and Technical Information of China (English)
YAO Jiang-Ming; L(U) Hong-Feng; Hillhouse Greg; MENG Jie
2008-01-01
Effects of core polarization and tensor coupling on the magnetic moments in 13Λ C,17Λ O,and 41Λ Ca Λ-hypernuclei are studied by employing the Dirac equation with scalar,vector and tensor potentials.It is found that the effect of core polarization on the magnetic moments is suppressed by Λ tensor coupling.The Λ tensor potential reduces the spin-orbit splitting of PΛ states considerably.However,almost the same magnetic moments are obtained using the hyperon wavefunction obtained via the Dirac equation either with or without the Λ tensor potential in the electromagnetic current vertex.The deviations of magnetic moments for pΛ states from the Schmidt values are found to increase with nuclear mass number.
Magnetic moment generation from non-minimal couplings in a scenario with Lorentz-symmetry violation
Energy Technology Data Exchange (ETDEWEB)
Belich, H. [Universidade Federal do Espirito Santo (UFES), Departamento de Fisica e Quimica, Vitoria, ES (Brazil); Universidade de Brasilia, International Center for Condensed Matter Physics, CP 04513, Brasilia, DF (Brazil); Grupo de Fisica Teorica Jose Leite Lopes, CP 91933, Petropolis, RJ (Brazil); Colatto, L.P. [CEFET-RJ UnED-Petropolis, Petropolis, RJ (Brazil); Grupo de Fisica Teorica Jose Leite Lopes, CP 91933, Petropolis, RJ (Brazil); Costa-Soares, T. [Universidade Federal de Juiz de Fora (UFJF), Colegio Tecnico Universitario, Juiz de Fora, MG (Brazil); Grupo de Fisica Teorica Jose Leite Lopes, CP 91933, Petropolis, RJ (Brazil); Helayel-Neto, J.A. [CBPF-Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, RJ (Brazil); Grupo de Fisica Teorica Jose Leite Lopes, CP 91933, Petropolis, RJ (Brazil); Orlando, M.T.D. [Universidade Federal do Espirito Santo (UFES), Departamento de Fisica e Quimica, Vitoria, ES (Brazil); Grupo de Fisica Teorica Jose Leite Lopes, CP 91933, Petropolis, RJ (Brazil)
2009-07-15
This paper deals with situations that illustrate how the violation of Lorentz symmetry in the gauge sector may contribute to magnetic moment generation of massive neutral particles with spin-1/(2) and spin-1. The procedure we adopt here is based on Relativistic Quantum Mechanics. We work out the non-relativistic regime that follows from the wave equation corresponding to a certain particle coupled to an external electromagnetic field and a background that accounts for the Lorentz-symmetry violation, and we thereby read off the magnetic dipole moment operator for the particle under consideration. We keep track of the parameters that govern the non-minimal electromagnetic coupling and the breaking of Lorentz symmetry in the expressions we get for the magnetic moments in the different cases we contemplate. Our claim is that the tiny magnetic dipole moment of truly-elementary neutral particles might signal Lorentz-symmetry violation. (orig.)
Perihelion Precession in Gravitational Field of Center Mass with Electric Charge and Magnetic Moment
Institute of Scientific and Technical Information of China (English)
WANG Jun; WANG Yong-Jiu
2005-01-01
With a perfect mathematical method by us, we obtain some expressions of the orbital effect for a test particle and some meaningful results in the gravitational field of the center mass with electric charge and magnetic moment.
Diagonal and transition magnetic moments of negative parity heavy baryons in QCD sum rules
Aliev, T M; Barakat, T; Savcı, M
2015-01-01
Diagonal and transition magnetic moments of the negative parity, spin-1/2 heavy baryons are studied in framework of the light cone QCD sum rules. By constructing the sum rules for different Lorentz structures, the unwanted contributions coming from negative (positive) to positive (negative) parity transitions are removed. It is obtained that the magnetic moments of all baryons, except $\\Lambda_b^0$, $\\Sigma_c^+$ and $\\Xi_c^{\\prime +}$, are quite large. It is also found that the transition magnetic moments between neutral negative parity heavy $\\Xi_Q^{\\prime 0}$ and $\\Xi_Q^0$ baryons are very small. Magnetic moments of the $\\Sigma_Q \\to \\Lambda_Q$ and $ \\Xi_Q^{\\prime \\pm} \\to \\Xi_Q^\\pm$ transitions are quite large and can be measured in further experiments.
Kholmetskii, A. L.; Missevitch, O. V.; Yarman, T.
2016-09-01
We consider the relativistic transformation of the magnetic dipole moment and disclose its physical meaning, shedding light on the related difficulties in the physical interpretation of classical electrodynamics in material media.
Direct evidence of Ni magnetic moment in TbNi{sub 2}Mn—X-ray magnetic circular dichroism
Energy Technology Data Exchange (ETDEWEB)
Yu, D.H., E-mail: dyu@ansto.gov.au [Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights, Sydney, NSW 2234 (Australia); Huang, Meng-Jie [National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan (China); Wang, J.L. [Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights, Sydney, NSW 2234 (Australia); School of Physical, Environmental and Mathematical Sciences, University of New South Wales, Canberra at the Australian Defense Force Academy, Sydney, ACT 2600 (Australia); Institute for Superconductivity and Electronic Materials, University of Wollongong, Wollongong, NSW 2522 (Australia); Su, Hui-Chia; Lin, Hong-Ji; Chen, Chien-Te [National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan (China); Campbell, S.J. [School of Physical, Environmental and Mathematical Sciences, University of New South Wales, Canberra at the Australian Defense Force Academy, Sydney, ACT 2600 (Australia)
2014-12-15
We have investigated the individual magnetic moments of Ni, Mn and Tb atoms in the intermetallic compound TbNi{sub 2}Mn in the Laves phase (magnetic phase transition temperature T{sub C} ∼131 K) by X-ray magnetic circular dichroism (XMCD) studies at 300 K, 80 K and 20 K. Analyses of the experimental results reveal that Ni atoms at 20 K in an applied magnetic field of 1 T carry an intrinsic magnetic moment of spin and orbital magnetic moment contributions 0.53±0.01 μ{sub B} and 0.05±0.01 μ{sub B}, respectively. These moment values are similar to those of the maximum saturated moment of Ni element. A very small magnetic moment of order <0.1 μ{sub B} has been measured for Mn. This suggests that Mn is antiferromagnetically ordered across the two nearly equally occupied sites of 16d and 8a. A magnetic moment of up to ∼0.3 μ{sub B} has been observed for the Tb atoms. Identification of a magnetic moment on the Ni atoms has provided further evidence for the mechanism of enhancement of the magnetic phase transition temperature in TbNi{sub 2}Mn compared with TbNi{sub 2} (T{sub C}∼37.5 K) and TbMn{sub 2} (T{sub C}∼54 K) due to rare earth–transition metal (R–T) and transition metal–transition metal (T–T) interactions. The behaviour of the X-ray magnetic circular dichroism spectra of TbNi{sub 2}Mn at 300 K, 80 K and 20 K – above and below the magnetic ordering temperature T{sub C} ∼131 K – is discussed. - Highlights: • We study the magnetic moment of TbNi{sub 2}Mn with XMCD. • We observe directly the Ni intrinsic magnetic moment in TbNi{sub 2}Mn. • We find that Mn ordered antiferromagnetically across the 16d and 8a sites. • We confirm the mechanism for increasing the magnetic phase transition temperature.
New limits on neutrino magnetic moments from low energy neutrino data
Canas, B C; Parada, A; Tortola, M; Valle, J W F
2016-01-01
Here we give a brief review on the current bounds on the general Majorana transition neutrino magnetic moments (TNMM) which cover also the conventional neutrino magnetic moments (NMM). Leptonic CP phases play a key role in constraining TNMMs. While the Borexino experiment is the most sensitive to the TNMM magnitudes, one needs complementary information from reactor and accelerator experiments in order to probe the complex CP phases.
Probing the magnetic moment of FePt micromagnets prepared by focused ion beam milling
Overweg, H.C.; Den Haan, A.M.J.; Eerkens, H.J.; Alkemade, P.F.A.; La Rooij, A.L.; Spreeuw, R.J.C.; Bossoni, L.; Oosterkamp, T.H.
2015-01-01
We investigate the degradation of the magnetic moment of a 300 nm thick FePt film induced by Focused Ion Beam (FIB) milling. A 1 μm × 8 μm rod is milled out of a film by a FIB process and is attached to a cantilever by electron beam induced deposition. Its magnetic moment is determined by frequency-
REC and NdFe magnetic moment irreversibility from temperature cycling
Energy Technology Data Exchange (ETDEWEB)
Hoyer, E.; Chin, J.W.G.; Shuman, D.
1985-10-01
Presented are the results of thermal cycling tests carried out on REC and NdFe samples, to determine the irreversible losses in room temperature open circuit magnetic moment. A stabilization prescription was developed for a REC alloy that will allow two 4 day/175/sup 0/C temperature cycles, which simulate two UHV bakeouts, with only a 0.35% average loss and a 0.65% loss variation in the room temperature open circuit magnetic moment after stabilization.
Abgaryan, V S; Ananikian, N. S.; Ananikyan, L. N.; Hovhannisyan, V.
2014-01-01
Thermal entanglement, magnetic and quadrupole moments properties of the mixed spin-1/2 and spin-1 Ising-Heisenberg model on a diamond chain are considered. Magnetization and quadrupole moment plateaus are observed for the antiferromagnetic couplings. Thermal negativity as a measure of quantum entanglement of the mixed spin system is calculated. Different behavior for the negativity is obtained for the various values of Heisenberg dipolar and quadrupole couplings. The intermediate plateau of t...
Elastic neutrino - electron scattering and potential effects of magnetic and electric dipole moments
W. Grimus(University of Vienna, Faculty of Physics, Boltzmanngasse 5, A-1090 Vienna, Austria); Schwetz, T.
2000-01-01
We consider elastic neutrino - electron scattering of solar neutrinos with magnetic moments and electric dipole moments, where the solar neutrino state at the scattering site is determined by the evolution in matter and solar magnetic fields of the initial electron neutrino state. We present the general cross section for an arbitrary superposition of active and sterile neutrino types with positive and negative helicities, with particular emphasis on the effect of transverse polarization, whic...
Energy Technology Data Exchange (ETDEWEB)
Lebedev, A.V.
2015-01-15
Magnetic susceptibility measurements were carried out for magnetite-based fluids over a wide temperature range. The fluids were stabilized with commonly used surfactants (fatty acids) and new surfactants (polypropylene glycol and tallow acids). The coefficients of temperature dependence of the particle magnetic moments were determined by fitting of the measured and calculated values of magnetic susceptibility. The influence of the inter-particle dipole–dipole interaction on the susceptibility was taken into account in the framework of A.O. Ivanov's model. The corrections for thermal expansion were determined by density measurements of the carrier fluid. The obtained values of temperature coefficients correlate to the solidification temperature of the fluid samples. For fluids with a low solidification temperature the value of the temperature coefficient of particle magnetization coincides with its value for bulk magnetite. - Highlights: • Susceptibility measurements made for magnetic fluids over a wide temperature range. • Temperature coefficients of particle magnetization found from susceptibility data. • The value of coefficients correlates to the solidification temperature of the fluid. • For the lowest solidification temperature the coefficient corresponds to that of bulk magnetite.
Gómez, A. M.; Torres, D. A.
2016-07-01
The experimental study of nuclear magnetic moments, using the Transient Field technique, makes use of spin-orbit hyperfine interactions to generate strong magnetic fields, above the kilo-Tesla regime, capable to create a precession of the nuclear spin. A theoretical description of such magnetic fields is still under theoretical research, and the use of parametrizations is still a common way to address the lack of theoretical information. In this contribution, a review of the main parametrizations utilized in the measurements of Nuclear Magnetic Moments will be presented, the challenges to create a theoretical description from first principles will be discussed.
Spontaneous magnetization and anomalous Hall effect in an emergent Dice lattice
Dutta, Omjyoti; Przysiężna, Anna; Zakrzewski, Jakub
2015-06-01
Ultracold atoms in optical lattices serve as a tool to model different physical phenomena appearing originally in condensed matter. To study magnetic phenomena one needs to engineer synthetic fields as atoms are neutral. Appropriately shaped optical potentials force atoms to mimic charged particles moving in a given field. We present the realization of artificial gauge fields for the observation of anomalous Hall effect. Two species of attractively interacting ultracold fermions are considered to be trapped in a shaken two dimensional triangular lattice. A combination of interaction induced tunneling and shaking can result in an emergent Dice lattice. In such a lattice the staggered synthetic magnetic flux appears and it can be controlled with external parameters. The obtained synthetic fields are non-Abelian. Depending on the tuning of the staggered flux we can obtain either anomalous Hall effect or its quantized version. Our results are reminiscent of Anomalous Hall conductivity in spin-orbit coupled ferromagnets.
Abgaryan, V. S.; Ananikian, N. S.; Ananikyan, L. N.; Hovhannisyan, V.
2015-02-01
Thermal entanglement, magnetic and quadrupole moments properties of the mixed spin-1/2 and spin-1 Ising-Heisenberg model on a diamond chain are considered. Magnetization and quadrupole moment plateaus are observed for the antiferromagnetic couplings. Thermal negativity as a measure of quantum entanglement of the mixed spin system is calculated. Different behavior for the negativity is obtained for the various values of Heisenberg dipolar and quadrupole couplings. The intermediate plateau of the negativity has been observed at the absence of the single-ion anisotropy and quadrupole interaction term. When dipolar and quadrupole couplings are equal there is a similar behavior of negativity and quadrupole moment.
Two dimensional electron gas confined over a spherical surface: Magnetic moment
Energy Technology Data Exchange (ETDEWEB)
Hernando, A; Crespo, P [Instituto de Magnetismo Aplicado, UCM-CSIC-ADIF, Las Rozas. P. O. Box 155, Madrid 28230 (Spain) and Dpto. Fisica de Materiales, Universidad Complutense (Spain); Garcia, M A, E-mail: antonio.hernando@adif.es [Instituto de Ceramica y Vidrio, CSIC c/Kelsen, 5 Madrid 28049 (Spain)
2011-04-01
Magnetism of capped nanoparticles, NPs, of non-magnetic substances as Au and ZnO is briefly reviewed. The source of the magnetization is discussed on the light of recent X-ray magnetic circular dichroism experiments. As magnetic dichroism analysis has pointed out impurity atoms bonded to the surface act as donor or acceptor of electrons that occupy the surface states. It is proposed that mesoscopic collective orbital magnetic moments induced at the surface states can account for the experimental magnetism characteristic of these nanoparticles. The total magnetic moment of the surface originated at the unfilled Fermi level can reach values as large as 10{sup 2} or 10{sup 3} Bohr magnetons.
Antonelli, V; Picariello, M; Pulido, J; Torrente-Lujan, E
2003-01-01
We present here a recopilation of recent results about the possibility of detecting solar electron antineutrinos produced by solar core and convective magnetic fields. These antineutrinos are predicted by spin-flavor oscillations at a significant rate even if this mechanism is not the leading solution to the SNP. Using the recent Kamland results and assuming a concrete model for antineutrino production by spin-flavor precession in the convective zone based on chaotic magnetic fields,we obtain bounds on the flux of solar antineutrinos, on the average conversion neutrino-antineutrino probability and on intrinsic neutrino magnetic moment. In the most conservative case, $\\mu\\lsim 2.5\\times 10^{-11} \\mu_B$ (95% CL). When studying the effects of a core magnetic field, we find in the weak limit a scaling of the antineutrino probability with respect to the magnetic field profile in the sense that the same probability function can be reproduced by any profile with a suitable peak field value. In this way the solar ele...
Guo, Zaibing
2015-05-01
The effect of interfacial intermixing on magnetization and anomalous Hall effect (AHE) in Co/Pd multilayers is studied by using rapid thermal annealing to enhance the interfacial diffusion. The dependence of saturation magnetization and coercivity on the temperature of rapid thermal annealing at 5 K is discussed. It is found that AHE is closely related to the relative thickness of the Co and Pd layers. Localized paramagnetism has been observed which destroys AHE, while AHE can be enhanced by annealing.
Kopferman, H; Massey, H S W
1958-01-01
Nuclear Moments focuses on the processes, methodologies, reactions, and transformations of molecules and atoms, including magnetic resonance and nuclear moments. The book first offers information on nuclear moments in free atoms and molecules, including theoretical foundations of hyperfine structure, isotope shift, spectra of diatomic molecules, and vector model of molecules. The manuscript then takes a look at nuclear moments in liquids and crystals. Discussions focus on nuclear paramagnetic and magnetic resonance and nuclear quadrupole resonance. The text discusses nuclear moments and nucl
Soft gamma-ray repeaters and anomalous X-ray pulsars as highly magnetized white dwarfs
Mukhopadhyay, Banibrata
2016-01-01
We show that the soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) can be explained as recently proposed highly magnetized white dwarfs (B-WDs). The radius and magnetic field of B-WDs are perfectly adequate to explain energies in SGRs/AXPs as the rotationally powered energy. While the highly magnetized neutron stars require an extra, observationally not well established yet, source of energy, the magnetized white dwarfs, yet following Chandrasekhar's theory (C-WDs), exhibit large ultra-violet luminosity which is observationally constrained from a strict upper limit.
Constraining neutrino magnetic moment with solar neutrino data
Tortola, M A
2003-01-01
We use solar neutrino data to derive stringent bounds on Majorana neutrino transition moments (TMs). Such moments, if present, would contribute to the neutrino-electron scattering cross section and hence alter the signal observed in Super-Kamiokande. Using the latest solar neutrino data, combined with the results of the reactor experiment KamLAND, we perform a simultaneous fit of the oscillation parameters and TMs. Furthermore, we include data from the reactor experiments Rovno, TEXONO and MUNU in our analysis, improving significantly the current constraints on TMs. A comparison with previous works shows that our bounds are the strongest and most general results presented up to now. Finally, we perform a simulation of the future Borexino experiment and show that it will improve the bounds from today's data by order of magnitude.
Anomalous Magnetic Excitations of Cooperative Tetrahedral Spin Clusters
DEFF Research Database (Denmark)
Prsa, K.; Rønnow, H.M.; Zaharko, O.;
2009-01-01
An inelastic neutron scattering study of Cu2Te2O5X2 (X=Cl, Br) shows strong dispersive modes with large energy gaps persisting far above T-N, notably in Cu2Te2O5Br2. The anomalous features: a coexisting unusually weak Goldstone-like mode observed in Cu2Te2O5Cl2 and the size of the energy gaps can...... cannot be explained by existing theories, such as our mean-field or random-phase approximation. We argue that our findings represent a new general type of behavior due to intercluster quantum fluctuations and call for development of a new theoretical approach....
A prototype vector magnetic field monitoring system for a neutron electric dipole moment experiment
Nouri, N; Brown, M A; Carr, R; Filippone, B; Osthelder, C; Plaster, B; Slutsky, S; Swank, C
2015-01-01
We present results from a first demonstration of a magnetic field monitoring system for a neutron electric dipole moment experiment. The system is designed to reconstruct the vector components of the magnetic field in the interior measurement region solely from exterior measurements.
Supernova neutrino signals by liquid Argon detector and neutrino magnetic moment
Yoshida, Takashi; Kimura, Keiichi; Kawagoe, Shio; Kajino, Toshitaka; Yokomakura, Hidekazu
2011-01-01
We study electron-neutrino and electron-antineutrino signals from a supernova with strong magnetic field detected by a 100 kton liquid Ar detector. The change of neutrino flavors by resonant spin-flavor conversions, matter effects, and neutrino self-interactions are taken into account. Different neutrino signals, characterized by neutronization burst event and the total event numbers of electron-neutrinos and electron-antineutrinos, are expected with different neutrino oscillation parameters and neutrino magnetic moment. Observations of supernova neutrino signals by a 100 kton liquid Ar detector would constrain oscillation parameters as well as neutrino magnetic moment in either normal and inverted mass hierarchies.
Energy Technology Data Exchange (ETDEWEB)
Pisane, K.L. [Department of Physics & Astronomy, West Virginia University, Morgantown, WV 26506 (United States); Despeaux, E.C. [Department of Pharmaceutical Sciences, West Virginia University, Morgantown, WV 26506 (United States); Seehra, M.S., E-mail: mseehra@wvu.edu [Department of Physics & Astronomy, West Virginia University, Morgantown, WV 26506 (United States)
2015-06-15
The role of particle size distribution inherently present in magnetic nanoparticles (NPs) is examined in considerable detail in relation to the measured magnetic properties of oleic acid-coated maghemite (γ-Fe{sub 2}O{sub 3}) NPs. Transmission electron microscopy (TEM) of the sol–gel synthesized γ-Fe{sub 2}O{sub 3} NPs showed a log-normal distribution of sizes with average diameter 〈D〉=7.04 nm and standard deviation σ=0.78 nm. Magnetization, M, vs. temperature (2–350 K) of the NPs was measured in an applied magnetic field H up to 90 kOe along with the temperature dependence of the ac susceptibilities, χ′ and χ″, at various frequencies, f{sub m}, from 10 Hz to 10 kHz. From the shift of the blocking temperature from T{sub B}=35 K at 10 Hz to T{sub B}=48 K at 10 kHz, the absence of any significant interparticle interaction is inferred and the relaxation frequency f{sub o}=2.6×10{sup 10} Hz and anisotropy constant K{sub a}=5.48×10{sup 5} erg/cm{sup 3} are determined. For T
On Intrinsic Magnetic Moments In Black Hole Candidates
Robertson, S L; Robertson, Stanley L.; Leiter, Darryl J.
2003-01-01
In previous work we found that many of the spectral properties of low mass x-ray binaries, including galactic black hole candidates could be explained by a magnetic propeller model that requires an intrinsically magnetized central object. Here we describe how the Einstein field equations of General Relativity and equipartition magnetic fields permit the existence of highly red shifted, extremely long lived, collapsing, radiating objects. We examine the properties of these collapsed objects and discuss characteristics that might lead to their confirmation as the source of black hole candidate phenomena.
Tang, Jiqiang; Xiang, Biao; Zhang, Yongbin
2014-07-01
For a magnetically suspended control moment gyroscope, stiffness and damping of magnetic bearing will influence modal frequency of a rotor. In this paper the relationship between modal frequency and stiffness and damping has been investigated. The mathematic calculation model of axial passive magnetic bearing (PMB) stiffness is developed. And PID control based on internal model control is introduced into control of radial active magnetic bearing (AMB), considering the radial coupling of axial PMB, a mathematic calculation model of stiffness and damping of radial AMB is established. According to modal analysis, the relationship between modal frequency and modal shapes is achieved. Radial vibration frequency is mainly influenced by stiffness of radial AMB; however, when stiffness increases, radial vibration will disappear and a high frequency bending modal will appear. Stiffness of axial PMB mainly affects the axial vibration mode, which will turn into high-order bending modal. Axial PMB causes bigger influence on torsion modal of the rotor.
Anomalous origin of the occipital artery diagnosed by magnetic resonance angiography
Energy Technology Data Exchange (ETDEWEB)
Uchino, Akira; Saito, Naoko; Mizukoshi, Waka; Okada, Yoshitaka [Saitama Medical University International Medical Center, Department of Diagnostic Radiology, Hidaka, Saitama (Japan)
2011-11-15
It is well known that the occipital artery (OA) can arise from the internal carotid artery (ICA) or vertebral artery (VA). However, the incidence of an anomalously originating OA has not been reported. We investigate its incidence and characteristic features on magnetic resonance angiography (MRA). We retrospectively reviewed MRA images of 2,866 patients that included the carotid bifurcation; images were obtained using a standard noncontrast MRA protocol and two 1.5-T MR units. We diagnosed six cases (seven arteries) of anomalously originating OA, which represented an incidence of 0.21%. The OA arose from the ICA in four patients (five arteries), from the carotid bifurcation in one, and from the VA in one. Five of the seven arteries occurred on the right. Anomalously originating OA is rare and occurs with right-side predominance. Correct diagnosis is necessary before or during cerebral angiography, especially when selective catheterization to the OA is required. (orig.)
Magnetic moments in chemically ordered mass-selected CoPt and FePt clusters
Energy Technology Data Exchange (ETDEWEB)
Dupuis, V., E-mail: Veronique.Dupuis@univ-lyon1.fr [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex (France); Khadra, G.; Linas, S.; Hillion, A. [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex (France); Gragnaniello, L. [Institute of Condensed Matter Physics, EPFL, CH-1015 Lausanne (Switzerland); Tamion, A.; Tuaillon-Combes, J.; Bardotti, L.; Tournus, F. [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex (France); Otero, E.; Ohresser, P. [Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin BP 48, F-91192 Gif-sur-Yvette Cedex (France); Rogalev, A.; Wilhelm, F. [European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex (France)
2015-06-01
By combining high photon flux and chemical selectivity, X-ray absorption spectroscopy and X-ray magnetic circular dichroism (XMCD) have been used to study the magnetism of CoPt and FePt clusters before and after their transition to the chemically ordered L1{sub 0}-like phase. Compared to the bulk, we find larger magnetic spin and orbital moments of Fe, Co and Pt atoms in nanoalloys. - Highlights: • Study of magnetism on well-defined CoPt and FePt clusters embedded in carbon matrix • X-ray magnetic circular dichroism (XMCD) at each specific Fe, Co and Pt edges, before and after annealing to induce transition to the chemically L1{sub 0}-like phase. • Quantitative values of the spin and orbital magnetic moments of Co (resp. Fe) and Pt after the chemical ordering transition. • Specific nanoalloy effects.
Magnetic Moment Formation in Graphene Detected by Scattering of Pure Spin Currents
Swartz, Adrian; McCreary, Kathy; Chen, Jen-Ru; Han, Wei; Fabian, Jaroslav; Kawakami, Roland
2013-03-01
Graphene's 2D nature and high surface sensitivity have led to fascinating predictions for induced spin-based phenomena through careful control of adsorbates, including the extrinsic spin Hall effect, band gap opening, and induced magnetism. By taking advantage of atomic scale control provided by MBE, we have investigated deposition of adsorbates and their interactions with graphene. Spin transport measurements performed in-situ during systematic introduction of atomic hydrogen demonstrated that hydrogen adsorbed on graphene forms magnetic moments that couple via exchange to the injected spin current. The observed behavior is quantitatively explained utilizing a phenomenological theory for scattering of pure spin currents by localized magnetic moments. Lattice vacancies show similar behavior, indicating that the moments originate from so called pz-orbital defects. On the other hand, experiments with charge impurity scatterers such as Mg and Au, are noticeably absent of features related to magnetic moment formation. Furthermore, we observe gate dependent effective exchange fields due to the spin-spin coupling between conduction electrons and magnetic moments, which are of interest for novel phenomena and spintronic functionality but have not been seen previously in graphene.
EM Induction Experiment to Determine the Moment of a Magnet
Najiya Maryam, K. M.
2014-01-01
If we drop a magnet through a coil, an emf is induced in the coil according to Faraday's law of electromagnetic induction. Here, such an experiment is done using expEYES kit. The plot of emf versus time has a specific shape with two peaks. A theoretical analysis of this graph is discussed here for both short and long cylindrical magnets.…
Anomalous shift of magnetic diffuse scattering studied by neutron diffraction
Energy Technology Data Exchange (ETDEWEB)
Prokes, K [Helmholtz Centre Berlin for Materials and Energy, SF-2, Glienicker Strasse 100, 14109 Berlin (Germany); Lander, G H [European Commission, JRC, Institute for Transuranium Elements, Postfach 2340, 76125 Karlsruhe (Germany); Bernhoeft, N [CEA Grenoble, DRFMC/SPSMS, F-38054 Grenoble (France)], E-mail: prokes@helmholtz-berlin.de
2009-07-15
Neutron diffraction results, in the vicinity of the magnetic phase transition of USb and MnF{sub 2}, are reported. The thermal evolution of the magnetic diffuse signal and nuclear Bragg reflections demonstrate that the centre of gravity of the magnetic signals does not lie at the predicted position as calculated from nuclear reflections. This phenomenon, called the q-shift, was first found using resonance x-ray scattering (RXS). The present results show that, (i) the effect is not an artefact of RXS and is also found with neutrons (ii) that the effect arises from the bulk of the sample and is not restricted to the near surface layer ({approx}2000 A) associated with the RXS probe in actinide systems, (iii) the effect is not restricted to actinide compounds.
Li, Hao-Song; Chen, Xiao-Lin; Deng, Wei-Zhen; Zhu, Shi-Lin
2016-01-01
We have systematically investigated the magnetic moments and magnetic form factors of the decuplet baryons to the next-to-next-leading order in the framework of the heavy baryon chiral perturbation theory. Our calculation includes the contributions from both the intermediate decuplet and octet baryon states in the loops. We also calculate the charge and magnetic dipole form factors of the decuplet baryons. Our results may be useful to the chiral extrapolation of the lattice simulations of the decuplet electromagnetic properties.
Magnetic moment interactions in the e--e+ system
International Nuclear Information System (INIS)
We have studied the possible existence of quasibound states of an electron-positron pair due to their magnetic interaction in the framework of the equations suggested by Barut et al. We derive radial equations for all angular quantum numbers of the e--e+ system and show, in detail, that Barut's equations does not give a consistent, physically satisfactory description of positronium, except in the non-relativistic approximation (up to terms of order m α2). Moreover, we do not find evidence that the effective potentials occurring in the radial equations support magnetic resonances of the e--e+ system at short particle distances ('micropositronium'). (orig.)
Magnetic moments of cascade baryons with strange sea in statistical model
International Nuclear Information System (INIS)
Study of hadrons can help to enrich our knowledge of its structure. Various recent experimental facilities at BASE, COMPASS etc. have provided opportunities for measurements of hadronic properties with an additional strangeness degree of freedom and search for exotic particles. Experimentally, at present magnetic moments of Δ++, Δ0 and Ω- are known. Magnetic moments of decuplet particles have not been measured experimentally because the particles decay strongly and thus do not live long enough. The present work analyses the contribution of sea-quarks to magnetic moment of cascade baryons of JP=3/2+ decuplet. For this, the methodology is based on the statistical model presented. The results are compared with the predictions of other models
The Impact of Neutrino Magnetic Moments on the Evolution of Massive Stars
Heger, Alexander; Giannotti, Maurizio; Cirigliano, Vincenzo
2008-01-01
We explore the sensitivity of massive stars to the neutrino magnetic moment. We find that the additional cooling due to the neutrino magnetic moment brings about qualitative changes to the structure and evolution of stars in the mass window 7 Msun < M < 18 Msun, rather than simply changing the time scales for the burning. We describe some of the consequences of this modified evolution: the shifts in the threshold masses for creating core-collapse supernovae and oxygen-neon-magnesium white dwarfs and the appearance of a new type of supernova in which a partial carbon-oxygen core explodes within a massive star. The resulting sensitivity to the magnetic moment is at the level of (2-4) * 10^{-11} \\mu_B.
Egan, R; Philippe, M; Wera, L; Fagnard, J F; Vanderheyden, B; Dennis, A; Shi, Y; Cardwell, D A; Vanderbemden, P
2015-02-01
We report the design and construction of a flux extraction device to measure the DC magnetic moment of large samples (i.e., several cm(3)) at cryogenic temperature. The signal is constructed by integrating the electromotive force generated by two coils wound in series-opposition that move around the sample. We show that an octupole expansion of the magnetic vector potential can be used conveniently to treat near-field effects for this geometrical configuration. The resulting expansion is tested for the case of a large, permanently magnetized, type-II superconducting sample. The dimensions of the sensing coils are determined in such a way that the measurement is influenced by the dipole magnetic moment of the sample and not by moments of higher order, within user-determined upper bounds. The device, which is able to measure magnetic moments in excess of 1 A m(2) (1000 emu), is validated by (i) a direct calibration experiment using a small coil driven by a known current and (ii) by comparison with the results of numerical calculations obtained previously using a flux measurement technique. The sensitivity of the device is demonstrated by the measurement of flux-creep relaxation of the magnetization in a large bulk superconductor sample at liquid nitrogen temperature (77 K). PMID:25725888
Direct high-precision measurement of the magnetic moment of the proton
Mooser, A; Blaum, K; Franke, K; Kracke, H; Leiteritz, C; Quint, W; Rodegheri, C C; Smorra, C; Walz, J
2014-01-01
The spin-magnetic moment of the proton $\\mu_p$ is a fundamental property of this particle. So far $\\mu_p$ has only been measured indirectly, analysing the spectrum of an atomic hydrogen maser in a magnetic field. Here, we report the direct high-precision measurement of the magnetic moment of a single proton using the double Penning-trap technique. We drive proton-spin quantum jumps by a magnetic radio-frequency field in a Penning trap with a homogeneous magnetic field. The induced spin-transitions are detected in a second trap with a strong superimposed magnetic inhomogeneity. This enables the measurement of the spin-flip probability as a function of the drive frequency. In each measurement the proton's cyclotron frequency is used to determine the magnetic field of the trap. From the normalized resonance curve, we extract the particle's magnetic moment in units of the nuclear magneton $\\mu_p=2.792847350(9)\\mu_N$. This measurement outperforms previous Penning trap measurements in terms of precision by a factor...
Knowles, R.
1982-07-01
A general theory of moments for electrodynamic magnetic levitation systems has been developed using double Fourier series and dynamic circuit principles. Both employ Parseval's theorem using either wave constant derivatives or the polar waveconstant principle of the Fourier-Bessel/double Fourier series equivalence. A method for calculating angular derivatives of moments and forces is explained, and for all of these methods comparisons are made with experimental results obtained for single and split rail configurations. Extensions of dynamic circuit theory for tilted nonflat and circular magnets are also explained.
Magnetic moment formation due to arsenic vacancies in LaFeAsO-derived superconductors.
Kikoin, Konstantin; Drechsler, Stefan-Ludwig; Koepernik, Klaus; Málek, Jiři; van den Brink, Jeroen
2015-07-14
Arsenic vacancies in LaFeAsO-derived superconductors are nominally non-magnetic defects. However, we find from a microscopic theory in terms of an appropriately modified Anderson-Wolff model that in their vicinity local magnetic moments form. They can arise because removing an arsenic atom breaks four strong, covalent bonds with the neighboring iron atoms. The moments emerging around an arsenic vacancy orient ferromagnetically and cause a substantial enhancement of the paramagnetic susceptibility in both the normal and superconducting state. The qualitative model description is supported by first principles band structure calculations of the As-vacancy related defect spectrum within a larger supercell.
Leading-order decuplet contributions to the baryon magnetic moments in chiral perturbation theory
Energy Technology Data Exchange (ETDEWEB)
Geng, L.S. [Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, 46071-Valencia (Spain); Camalich, J. Martin [Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, 46071-Valencia (Spain)], E-mail: camalich@ific.uv.es; Vacas, M.J. Vicente [Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, 46071-Valencia (Spain)
2009-06-01
We extend an earlier study of the baryon magnetic moments in chiral perturbation theory by the explicit inclusion of the spin-3/2 decuplet resonances. We find that the corrections induced by these heavier degrees of freedom are relatively small in a covariant framework where unphysical spin-1/2 modes are removed. Consequently, implementing the leading SU(3)-breaking corrections given by both the baryon and decuplet contributions, we obtain a description of the baryon-octet magnetic moments that is better than the Coleman-Glashow relations. Finally, we discuss the uncertainties and compare between heavy baryon and covariant approaches.
Leading-order decuplet contributions to the baryon magnetic moments in Chiral Perturbation Theory
Geng, L S; Vacas, M J Vicente
2009-01-01
We extend an earlier study of the baryon magnetic moments in chiral perturbation theory by the explicit inclusion of the spin-3/2 decuplet resonances. We find that the corrections induced by these heavier degrees of freedom are relatively small in a covariant framework where unphysical spin-1/2 modes are removed. Consequently, implementing the leading SU(3)-breaking corrections given by both the baryon and decuplet contributions, we obtain a description of the baryon-octet magnetic moments that is better than the Coleman-Glashow relations. Finally, we discuss the uncertainties and compare between heavy baryon and covariant approaches.
SNO results and neutrino magnetic moment solution to the solar neutrino problem
Indian Academy of Sciences (India)
Debasish Majumdar
2002-01-01
We have analysed the solar neutrino data obtained from chlorine, gallium and Super-Kamiokande (SK) experiments (1258 days) and also the new results that came from Sudbury Neutrino Observatory (SNO) charge current (CC) and elastic scattering (ES) experiments considering that the solar neutrino deﬁcit is due to the interaction of neutrino transition magnetic moment with the solar magnetic ﬁeld. We have also analysed the moments of the spectrum of scattered electrons at SK. Another new feature in the analysis is that for the global analysis, we have replaced the spectrum by its centroid.
Two Models Relevant to the Interaction of a Point Charge and a Magnetic Moment
Boyer, Timothy H
2012-01-01
An understanding of the interaction of a point charge and a magnetic moment is crucial for understanding the experiments involving electromagnetic momentum carried by permeable materials as well as the experimentally-observed Aharonov-Bohm and Aharonov-Casher phase shifts. Here we present two simple models for a magnetic moment which have vastly different interactions with a distant point charge. It is suggested that a satisfactory theoretical understanding of the interaction is still lacking and that the "hidden momentum" interpretation has been introduced into the textbook literature prematurely.
Energy Technology Data Exchange (ETDEWEB)
Gouvêa, André de; Shalgar, Shashank, E-mail: degouvea@northwestern.edu, E-mail: shashank@northwestern.edu [Department of Physics and Astronomy, Northwestern University, Evanston IL 60208-3112 (United States)
2013-04-01
We demonstrate the non-negligible effect of transition magnetic moments on three-flavor collective oscillations of Majorana neutrinos in the core of type-II supernovae, within the single-angle approximation. We argue that data from a galactic supernova in conjunction with terrestrial experiments can potentially give us clues about the non-zero nature of neutrino transition magnetic moments if these are Majorana fermions, even if their values are as small as those predicted by the Standard Model augmented by nonzero neutrino Majorana masses.
Magnetic moment formation due to arsenic vacancies in LaFeAsO-derived superconductors.
Kikoin, Konstantin; Drechsler, Stefan-Ludwig; Koepernik, Klaus; Málek, Jiři; van den Brink, Jeroen
2015-01-01
Arsenic vacancies in LaFeAsO-derived superconductors are nominally non-magnetic defects. However, we find from a microscopic theory in terms of an appropriately modified Anderson-Wolff model that in their vicinity local magnetic moments form. They can arise because removing an arsenic atom breaks four strong, covalent bonds with the neighboring iron atoms. The moments emerging around an arsenic vacancy orient ferromagnetically and cause a substantial enhancement of the paramagnetic susceptibility in both the normal and superconducting state. The qualitative model description is supported by first principles band structure calculations of the As-vacancy related defect spectrum within a larger supercell. PMID:26169486
Artificial ferroelectricity due to anomalous Hall effect in magnetic tunnel junctions
Vedyayev, A.; Ryzhanova, N.; Strelkov, N.; Dieny, B
2012-01-01
We theoretically investigated Anomalous Hall Effect (AHE) and Spin Hall Effect (SHE) transversally to the insulating spacer O, in magnetic tunnel junctions of the form F/O/F where F are ferromagnetic layers and O represents a tunnel barrier. We considered the case of purely ballistic (quantum mechanical) transport, taking into account the assymetric scattering due to spin-orbit interaction in the tunnel barrier. AHE and SHE in the considered case have a surface nature due to proximity effect....
Prediction of magnetic moment collapse in ZrFe{sub 2} under hydrostatic pressure
Energy Technology Data Exchange (ETDEWEB)
Zhang, Wenxu; Zhang, Wanli [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)
2015-04-28
Electronic structure and magnetic properties of ZrFe{sub 2} in the cubic Laves phase are investigated by calculations based on density functional theory. The magnetic moment decreases with the increase of the hydrostatic pressure in an unusual way: Two-step magnetic collapse is predicted. The first one is a continuous change from 1.53 μ{sub B}/Fe to 0.63 μ{sub B}/Fe at about 3.6 GPa, and the other is from 0.25 μ{sub B}/Fe to the nonmagnetic state at about 15 GPa in a first order manner under the local spin density approximation of the exchange correlation potential. A metastable state with intermediate spin moment about 0.15 μ{sub B}/Fe may exist before that. We understand this process by the changes of density of states during it. The magnetic moment decreases under the pressure in the vicinity of the experimental lattice constant with dlnm/dp=−0.038 GPa{sup −1}. The spontaneous volume magnetostriction is 3.6%, which is huge enough to find potential applications in magnetostriction actuators and sensors. We suggest that the Invar effect of this compound may be understood when considering the magnetic moment variation according to the magnetostrictive model of Invar.
Energy Technology Data Exchange (ETDEWEB)
Stone, N. J., E-mail: n.stone@physics.ox.ac.uk [Department of Physics and Astronomy, University of Tennessee, Knoxville Tennessee 37996 (United States)
2015-09-15
The most recent tabulations of nuclear magnetic dipole and electric quadrupole moments have been prepared and published by the Nuclear Data Section of the IAEA, Vienna [N. J. Stone, Report No. INDC(NDS)-0650 (2013); Report No. INDC(NDS)-0658 (2014)]. The first of these is a table of recommended quadrupole moments for all isotopes in which all experimental results are made consistent with a limited number of adopted standards for each element; the second is a combined listing of all measurements of both moments. Both tables cover all isotopes and energy levels. In this paper, the considerations relevant to the preparation of both tables are described, together with observations as to the importance and (where appropriate) application of necessary corrections to achieve the “best” values. Some discussion of experimental methods is included with emphasis on their precision. The aim of the published quadrupole moment table is to provide a standard reference in which the value given for each moment is the best available and for which full provenance is given. A table of recommended magnetic dipole moments is in preparation, with the same objective in view.
International Nuclear Information System (INIS)
The most recent tabulations of nuclear magnetic dipole and electric quadrupole moments have been prepared and published by the Nuclear Data Section of the IAEA, Vienna [N. J. Stone, Report No. INDC(NDS)-0650 (2013); Report No. INDC(NDS)-0658 (2014)]. The first of these is a table of recommended quadrupole moments for all isotopes in which all experimental results are made consistent with a limited number of adopted standards for each element; the second is a combined listing of all measurements of both moments. Both tables cover all isotopes and energy levels. In this paper, the considerations relevant to the preparation of both tables are described, together with observations as to the importance and (where appropriate) application of necessary corrections to achieve the “best” values. Some discussion of experimental methods is included with emphasis on their precision. The aim of the published quadrupole moment table is to provide a standard reference in which the value given for each moment is the best available and for which full provenance is given. A table of recommended magnetic dipole moments is in preparation, with the same objective in view
Anisotropic Open Cosmological Models of Spin Matter with Magnetic Moment
Institute of Scientific and Technical Information of China (English)
SHENLi－ming; SUNNai－jiang; 等
2001-01-01
We have derived a set of field equations for a Weyssenhoff spin fluid including magnetic interacton among the spinning particles prevailling in spatially homogeneous,but anisotropically cosmological models of Bianchi type V based on Einstein-Cartan theory.We analyze the field equations in three different equations of states specified by p=1(1/3)ρand p=0,The analytical solutions found are non-singular provided that the combined energy arising from matter spin and magnetic interaction among particles overcomes the anisotropy energy in the Universe,We have also deduced that the minimum particle numers for the radiation(p=(1/3)ρ) and matter(p=0) epochs are 1088 and 10108 respectively.the minimum particle number for the state p=ρ is 1096,leading to the conclusion that we must consider the existence of neutrinos and other creation of particles and anti-particles under torsion and strong gravitational field in the early Universe.
Period Clustering of the Anomalous X-Ray Pulsars and Magnetic Field Decay in Magnetars.
Colpi; Geppert; Page
2000-01-20
We confront theoretical models for the rotational, magnetic, and thermal evolution of an ultramagnetized neutron star, or magnetar, with available data on the anomalous X-ray pulsars (AXPs). We argue that, if the AXPs are interpreted as magnetars, their clustering of spin periods between 6 and 12 s (observed at present in this class of objects), their period derivatives, their thermal X-ray luminosities, and the association of two of them with young supernova remnants can only be understood globally if the magnetic field in magnetars decays significantly on a timescale of the order of 104 yr.
Institute of Scientific and Technical Information of China (English)
郭远清; 黄光明; 林洁丽; 段传喜; 李奉延; 李津蕊; 刘煜炎
2001-01-01
An intracavity CO laser magnetic resonance spectrometer with homogeneous dc electric field applied via a pairof parallel Stark plates in the absorption cell is used to measure the electric dipole moments of free radicals.Taking advantage of the high sensitivity and high resolution of this technique and the Stark effect, highlyresolved saturated absorption spectra of the ν ＝ 1 - 0 transition of 15 N16 O in the ground state X2 П3/2 have beensuccessfully observed in the presence of a low electric field. The electric dipole moment of NO in the electronicground state is determined asμ ＝ 0.1566 ± 14D (Debye) from the analysis of the observed spectra, confirmingthat, combined with the Stark field, the laser magnetic resonance technique can be an effective and reliableapproach for the precise measurement of electric dipole moments of free radicals, especially unstable ones.
Magnetic dipole moment of the doubly closed-shell plus one proton nucleus $^{49}$Sc
Gaulard, C V; Walters, W; Nishimura, K; Muto, S; Bingham, C R
It is proposed to measure the magnetic moment of $^{49}$Sc by the Nuclear Magnetic Resonance on Oriented Nuclei (NMR-ON) method using the NICOLE on-line nuclear orientation facility. $^{49}$Sc is the neutron rich, doubly closed-shell, nucleus $^{48}$Ca plus one proton. Results will be used to deduce the effective g-factors in the $^{48}$Ca region with reference to nuclear structure and meson exchange current effects.
Anomalous evolution of interfaces in Fe/Ag magnetic multilayer
Sharma, Gagan; Gupta, Ranjeeta; Kumar, Dileep; Gupta, Ajay
2013-12-01
Interfaces greatly influence the magnetic properties of multilayer nanostructures. In the present work, the x-ray standing wave (XSW) technique along with conversion electron Mössbauer spectroscopy have been used to study the evolution of interfaces in Fe/Ag system as a function of thermal annealing. The XSW technique has sufficient depth resolution so as to determine the concentration profiles of Fe across the two interfaces, namely Fe-on-Ag and Ag-on-Fe independently. In as-deposited Ag/Fe/Ag trilayer, Fe-on-Ag interface has a substantially higher roughness of 1.3 nm as compared to 0.9 nm of Ag-on-Fe interface. It is shown that the observed difference in the roughness of the two interfaces is due to a substantial intermixing between Fe and Ag occurring preferentially at Fe-on-Ag interface. With thermal annealing, the two interfaces exhibit opposite behaviour; while Fe-on-Ag interface exhibits an initial sharpening, Ag-on-Fe interface exhibits a monotonous broadening. Two competing processes occur at the interfaces, (i) interface sharpening as a result of de-mixing, driven by a large positive heat of mixing between Fe and Ag and (ii) increase in topological roughness due to increased thermal agitation. This results in a non-monotonous variation in the roughness of Fe-on-Ag interface. At sufficiently high temperature the layered structure is completely destroyed, leading to formation of Fe and Ag nanoparticles.
Nucleon polarizabilities and Delta-resonance magnetic moment in chiral EFT
Pascalutsa, Vladimir
2010-01-01
Recent chiral EFT calculations of nucleon polarizabilities reveal a problem in the current empirical determination of proton's electromagnetic polarizabilities. We also report on the progress in the empirical determination of the $\\Delta$(1232)-resonance magnetic moment in the process of $\\gamma p \\to p \\pi^0 \\gamma'$ measured at MAMI.
Nucleon polarizabilities and Δ-resonance magnetic moment in chiral EFT
International Nuclear Information System (INIS)
Recent chiral EFT calculations of nucleon polarizabilities reveal a problem in the current empirical determination of proton's electromagnetic polarizabilities. We also report on the progress in the empirical determination of the Δ(1232)-resonance magnetic moment in the process of γp→pπ0γ' measured at MAMI.
Masses and magnetic moments of heavy flavour baryons in hyper central model
Patel, Bhavin; Raiyz, Ajay Kumar; Vinodkumar, P. C.
2008-05-01
We employ the hyper central approach to study the masses and magnetic moments of the baryons constituting single charm and beauty quark. The confinement potential is assumed in the hyper central co-ordinates of the coulomb plus power potential form.
Masses and magnetic moments of heavy flavour baryons in hyper central model
Patel, Bhavin; Vinodkumar, P C
2008-01-01
We employ the hyper central approach to study the masses and magnetic moments of the baryons constituting single charm and beauty quark. The confinement potential is assumed in the hyper central co-ordinates of the coulomb plus power potential form.
Local magnetic moment and hyperfine field in hydrogenated iron and iron-vanadium alloy
Energy Technology Data Exchange (ETDEWEB)
Elzain, M.E.; Yousif, A.A. [Sultan Qaboos Univ., Al-Khod (Oman). Dept. of Phys.
1994-11-01
The local magnetic moment {mu} and hyperfine field B{sub hf} at Fe and V sites in hydrogenated iron and iron-vanadium were calculated using the discrete variational method. The variations in {mu} and B{sub hf} with H occupation of the octahedral (O) site were considered. It was found that when H occupies the O site neighbouring an Fe atom, both local moment and hyperfine field at this atom decrease linearly with increasing number of H atoms. The rate of decrease is larger for Fe in iron as compared to iron in vanadium. On the other hand, when H resides at an O site next neighbouring an Fe atom, whether in iron metal or in iron-vanadium, the Fe magnetic moment increases slowly, while the hyperfine field remains almost constant. The V moment in iron, which is negative ({approx} -0.83 {mu}{sub B}), becomes less negative ({approx} -0.30 {mu}{sub B}) as H occupies the neighboring O sites, whereas slight changes occur ({approx} -0.88 {mu}{sub B}) when H is at the next neighbouring O site. The net effect of H on Fe in iron is to decrease the average magnetic moment at a rate of {approx} 1.2 {mu}{sub B} per H/Fe for low H content. On the other hand, the average Fe moment in an iron-vanadium alloy increases if H resides at O sites which are immediate neigbours of V and next neighbours of Fe. This may explain the development of a magnetic state on hydrogenation of Fe-V alloys, which is exhibited by the specific heat and susceptibility measurements. The changes in the isomer shift were found to agree with experimental trends. (orig.)
Room-temperature ferromagnetism with high magnetic moment in Cu-doped AlN single crystal whiskers
Institute of Scientific and Technical Information of China (English)
姜良宝; 刘宇; 左思斌; 王文军
2015-01-01
Ferromagnetism is investigated in high-quality Cu-doped AlN single crystal whiskers. The whiskers exhibit room-temperature ferromagnetism with a magnetic moment close to the results from first-principles calculations. High crys-tallinity and low Cu concentrations are found to be indispensable for high magnetic moments. The difference between the experimental and theoretical moment values is explored in terms of the infl uence of nitrogen vacancies. The calculated results demonstrate that nitrogen vacancies can reduce the magnetic moments of Cu atom.
Baryshevsky, Vladimir
2013-01-01
It is shown that in the experiments for search of the EDM of an electron (atom, molecule) the T-odd magnetic moment induced by an electric field and the T-odd electric dipole moment induced by a magnetic field will be also measured. It is discussed how to distinguish these contributions.
Anomalous Magnetohydrodynamics
Giovannini, Massimo
2013-01-01
Anomalous symmetries induce currents which can be parallel rather than orthogonal to the hypermagnetic field. Building on the analogy with charged liquids at high magnetic Reynolds numbers, the persistence of anomalous currents is scrutinized for parametrically large conductivities when the plasma approximation is accurate. Different examples in globally neutral systems suggest that the magnetic configurations minimizing the energy density with the constraint that the helicity be conserved co...
Anomalous wave structure in magnetized materials described by non-convex equations of state
Energy Technology Data Exchange (ETDEWEB)
Serna, Susana, E-mail: serna@mat.uab.es [Departament de Matematiques, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain); Marquina, Antonio, E-mail: marquina@uv.es [Departamento de Matematicas, Universidad de Valencia, 46100 Burjassot, Valencia (Spain)
2014-01-15
We analyze the anomalous wave structure appearing in flow dynamics under the influence of magnetic field in materials described by non-ideal equations of state. We consider the system of magnetohydrodynamics equations closed by a general equation of state (EOS) and propose a complete spectral decomposition of the fluxes that allows us to derive an expression of the nonlinearity factor as the mathematical tool to determine the nature of the wave phenomena. We prove that the possible formation of non-classical wave structure is determined by both the thermodynamic properties of the material and the magnetic field as well as its possible rotation. We demonstrate that phase transitions induced by material properties do not necessarily imply the loss of genuine nonlinearity of the wavefields as is the case in classical hydrodynamics. The analytical expression of the nonlinearity factor allows us to determine the specific amount of magnetic field necessary to prevent formation of complex structure induced by phase transition in the material. We illustrate our analytical approach by considering two non-convex EOS that exhibit phase transitions and anomalous behavior in the evolution. We present numerical experiments validating the analysis performed through a set of one-dimensional Riemann problems. In the examples we show how to determine the appropriate amount of magnetic field in the initial conditions of the Riemann problem to transform a thermodynamic composite wave into a simple nonlinear wave.
Anomalous wave structure in magnetized materials described by non-convex equations of state
International Nuclear Information System (INIS)
We analyze the anomalous wave structure appearing in flow dynamics under the influence of magnetic field in materials described by non-ideal equations of state. We consider the system of magnetohydrodynamics equations closed by a general equation of state (EOS) and propose a complete spectral decomposition of the fluxes that allows us to derive an expression of the nonlinearity factor as the mathematical tool to determine the nature of the wave phenomena. We prove that the possible formation of non-classical wave structure is determined by both the thermodynamic properties of the material and the magnetic field as well as its possible rotation. We demonstrate that phase transitions induced by material properties do not necessarily imply the loss of genuine nonlinearity of the wavefields as is the case in classical hydrodynamics. The analytical expression of the nonlinearity factor allows us to determine the specific amount of magnetic field necessary to prevent formation of complex structure induced by phase transition in the material. We illustrate our analytical approach by considering two non-convex EOS that exhibit phase transitions and anomalous behavior in the evolution. We present numerical experiments validating the analysis performed through a set of one-dimensional Riemann problems. In the examples we show how to determine the appropriate amount of magnetic field in the initial conditions of the Riemann problem to transform a thermodynamic composite wave into a simple nonlinear wave
(129) Xe and (131) Xe nuclear magnetic dipole moments from gas phase NMR spectra.
Makulski, Włodzimierz
2015-04-01
(3) He, (129) Xe and (131) Xe NMR measurements of resonance frequencies in the magnetic field B0=11.7586 T in different gas phase mixtures have been reported. Precise radiofrequency values were extrapolated to the zero gas pressure limit. These results combined with new quantum chemical values of helium and xenon nuclear magnetic shielding constants were used to determine new accurate nuclear magnetic moments of (129) Xe and (131) Xe in terms of that of the (3) He nucleus. They are as follows: μ((129) Xe) = -0.7779607(158)μN and μ((131) Xe) = +0.6918451(70)μN . By this means, the new 'helium method' for estimations of nuclear dipole moments was successfully tested. Gas phase NMR spectra demonstrate the weak intermolecular interactions observed on the (3) He and (129) Xe and (131) Xe shielding in the gaseous mixtures with Xe, CO2 and SF6 .
Neutrino magnetic moments and low-energy solar neutrino-electron scattering experiments
Pastor, S; Semikoz, V B; Valle, José W F
1999-01-01
The scattering of solar neutrinos on electrons is sensitive to the neutrino magnetic moments through an interference of electromagnetic and weak amplitudes in the cross section. We show that future low-energy solar neutrino experiments with good angular resolution can be sensitive to the resulting azimuthal asymmetries in event number and should provide useful information on non-standard neutrino properties such as magnetic moments. We compare asymmetries expected at HELLAZ (mainly pp neutrinos) with those at the Kamiokande and Super-Kamiokande experiments (Boron neutrinos), both for the case of Dirac and Majorana neutrinos and discuss the advantages of low energies. Potentially interesting information on the solar magnetic fields may be accessible
Hadronic Light by Light Contributions to the Muon Anomalous Magnetic Moment With Physical Pions
Jin, Luchang; Christ, Norman; Hayakawa, Masashi; Izubuchi, Taku; Lehner, Christoph
2015-01-01
The current measurement of muonic $g - 2$ disagrees with the theoretical calculation by about 3 standard deviations. Hadronic vacuum polarization (HVP) and hadronic light by light (HLbL) are the two types of processes that contribute most to the theoretical uncertainty. The current value for HLbL is still given by models. I will describe results from a first-principles lattice calculation with a 139 MeV pion in a box of 5.5 fm extent. Our current numerical strategies, including noise reduction techniques, evaluating the HLbL amplitude at zero external momentum transfer, and important remaining challenges, in particular those associated with finite volume effects, will be discussed.
Muon Anomalous Magnetic Moment (g-2)_mu and the Randall-Sundrum Model
Kim, C S; Song, J; Song, Jeonghyeon
2001-01-01
We study the effects of the Kaluza-Klein gravitons in the Randall-Sundrum model on the recent BNL measurements of the muon (g-2) deviation from the standard model prediction. By examining the J-partial wave unitarity bounds of the elastic process \\gamma\\gamma\\to\\gamma\\gamma, the cut-off on the number of massive KK gravitons, n_c, has been introduced so that the reported \\Delta a_\\mu can be attributed to the RS effects with dozens (hundreds) of the n_c for \\Lambda_\\pi=1-2 TeV (3 TeV). We found that the recently measured \\Delta a_\\mu can be accommodated in the RS model, as providing valuable information on the validity of its effective theory.
Study of the anomalous magnetic moment of the muon computed from the Adler function
Della Morte, Michele; Herdoiza, Gregorio; Horch, Hanno; Jäger, Benjamin; Jüttner, Andreas; Meyer, Harvey; Wittig, Hartmut
2014-01-01
We compute the Adler function on the lattice from vacuum polarization data with twisted boundary conditions using numerical derivatives. The study is based on CLS ensembles with two flavours of $O(a)$ improved Wilson fermions. We extrapolate the lattice data for the Adler function to the continuum limit and to the physical pion mass and analyze its dependence on the momentum transfer. We discuss the application of this method to the extraction of the $u,d$ contribution to $a_\\mu^{\\mathrm{HLO}}$.
Lepton flavor violating Z' explanation of the muon anomalous magnetic moment
Altmannshofer, Wolfgang; Dev, P S Bhupal; Soni, Amarjit
2016-01-01
We discuss a minimal solution to the long-standing $(g-2)_\\mu$ anomaly in a simple extension of the Standard Model with an extra $Z'$ vector boson that has only flavor off-diagonal couplings to the second and third generation of leptons, i.e. $\\mu, \\tau, \
Decoherence-governed magnetic-moment dynamics of supported atomic objects
Gauyacq, Jean-Pierre; Lorente, Nicolás
2015-11-01
Due to the quantum evolution of molecular magnetic moments, the magnetic state of nanomagnets can suffer spontaneous changes. This process can be completely quenched by environment-induced decoherence. However, we show that for typical small supported atomic objects, the substrate-induced decoherence does change the magnetic-moment evolution but does not quell it. To be specific and to compare with experiment, we analyze the spontaneous switching between two equivalent magnetization states of atomic structures formed by Fe on Cu2N/Cu (1 0 0), measured by Loth et al (2012 Science 335 196-9). Due to the substrate-induced decoherence, the Rabi oscillations proper to quantum tunneling between magnetic states are replaced by an irreversible decay of long characteristic times leading to the observed stochastic magnetization switching. We show that the corresponding switching rates are small, rapidly decreasing with system’s size, with a 1/T thermal behavior and in good agreement with experiments. Quantum tunneling is recovered as the switching mechanism at extremely low temperatures below the μK range for a six-Fe-atom system and exponentially lower for larger atomic systems. The unexpected conclusion of this work is that experiments could detect the switching of these supported atomic systems because their magnetization evolution is somewhere between complete decoherence-induced stability and unobservably fast quantum-tunneling switching.
Decoherence-governed magnetic-moment dynamics of supported atomic objects
International Nuclear Information System (INIS)
Due to the quantum evolution of molecular magnetic moments, the magnetic state of nanomagnets can suffer spontaneous changes. This process can be completely quenched by environment-induced decoherence. However, we show that for typical small supported atomic objects, the substrate-induced decoherence does change the magnetic-moment evolution but does not quell it. To be specific and to compare with experiment, we analyze the spontaneous switching between two equivalent magnetization states of atomic structures formed by Fe on Cu2N/Cu (1 0 0), measured by Loth et al (2012 Science 335 196–9). Due to the substrate-induced decoherence, the Rabi oscillations proper to quantum tunneling between magnetic states are replaced by an irreversible decay of long characteristic times leading to the observed stochastic magnetization switching. We show that the corresponding switching rates are small, rapidly decreasing with system’s size, with a 1/T thermal behavior and in good agreement with experiments. Quantum tunneling is recovered as the switching mechanism at extremely low temperatures below the μK range for a six-Fe-atom system and exponentially lower for larger atomic systems. The unexpected conclusion of this work is that experiments could detect the switching of these supported atomic systems because their magnetization evolution is somewhere between complete decoherence-induced stability and unobservably fast quantum-tunneling switching. (paper)
Decoherence-governed magnetic-moment dynamics of supported atomic objects.
Gauyacq, Jean-Pierre; Lorente, Nicolás
2015-11-18
Due to the quantum evolution of molecular magnetic moments, the magnetic state of nanomagnets can suffer spontaneous changes. This process can be completely quenched by environment-induced decoherence. However, we show that for typical small supported atomic objects, the substrate-induced decoherence does change the magnetic-moment evolution but does not quell it. To be specific and to compare with experiment, we analyze the spontaneous switching between two equivalent magnetization states of atomic structures formed by Fe on Cu2N/Cu (1 0 0), measured by Loth et al (2012 Science 335 196-9). Due to the substrate-induced decoherence, the Rabi oscillations proper to quantum tunneling between magnetic states are replaced by an irreversible decay of long characteristic times leading to the observed stochastic magnetization switching. We show that the corresponding switching rates are small, rapidly decreasing with system's size, with a 1/T thermal behavior and in good agreement with experiments. Quantum tunneling is recovered as the switching mechanism at extremely low temperatures below the μK range for a six-Fe-atom system and exponentially lower for larger atomic systems. The unexpected conclusion of this work is that experiments could detect the switching of these supported atomic systems because their magnetization evolution is somewhere between complete decoherence-induced stability and unobservably fast quantum-tunneling switching. PMID:26471260
Magnetic structure of Yb2Pt2Pb : Ising moments on the Shastry-Sutherland lattice
Miiller, W.; Wu, L. S.; Kim, M. S.; Orvis, T.; Simonson, J. W.; GamŻa, M.; McNally, D. M.; Nelson, C. S.; Ehlers, G.; Podlesnyak, A.; Helton, J. S.; Zhao, Y.; Qiu, Y.; Copley, J. R. D.; Lynn, J. W.; Zaliznyak, I.; Aronson, M. C.
2016-03-01
Neutron diffraction measurements were carried out on single crystals and powders of Yb2Pt2Pb , where Yb moments form two interpenetrating planar sublattices of orthogonal dimers, a geometry known as Shastry-Sutherland lattice, and are stacked along the c axis in a ladder geometry. Yb2Pt2Pb orders antiferromagnetically at TN=2.07 K , and the magnetic structure determined from these measurements features the interleaving of two orthogonal sublattices into a 5 ×5 ×1 magnetic supercell that is based on stripes with moments perpendicular to the dimer bonds, which are along (110 ) and (-110 ) . Magnetic fields applied along (110 ) or (-110 ) suppress the antiferromagnetic peaks from an individual sublattice, but leave the orthogonal sublattice unaffected, evidence for the Ising character of the Yb moments in Yb2Pt2Pb that is supported by point charge calculations. Specific heat, magnetic susceptibility, and electrical resistivity measurements concur with neutron elastic scattering results that the longitudinal critical fluctuations are gapped with Δ E ≃0.07 meV .
Magnetic moment of single vortices in YBCO nano-superconducting particle: Eilenberger approach
Zakharchuk, I.; Sharafeev, A.; Belova, P.; Safonchik, M.; Traito, K. B.; Lähderanta, E.
2013-12-01
Temperature dependence of single vortex magnetic moment in nanosize superconducting particles is investigated in the framework of quasiclassical Eilenberger approach. Such nanoparticles can be used for preparation of high-quality superconducting thin films with high critical current density. In contrast to bulk materials where the vortex magnetic moment is totally determined by flux quantum, in nano-sized specimens (with characteristic size, D, much less than effective penetration depth, λeff) the quantization rule is violated and magnetic moment is proportional to D2/λ2eff(T). Due to strong repulsion between vortices in nanoparticles only a single vortex can be trapped in them. Because of small size of particles the screening current of the vortex is located near the vortex core where the current is quite high and comparable to depairing currents. Therefore, the superconducting electron density, ns, depends on the current value and the distance from the vortex core. This effect is especially important for superconductors having gap nodes, such as YBCO. The current dependence of ns in nanoparticles is analogous to the Volovik effect in flux-line lattice in bulk samples. The magnitude of the effect can be obtained by comparing the temperature dependence of magnetic moment in the vortex and in the Meissner states. In the last case the value of screening current is small and superconducting response to the external field is determined by London penetration depth. Because of importance of nonlinear and nonlocal effects, the quantum mechanical Eilenberger approach is applied for description of the vortex in nanoparticles. The flattening of 1/λ2eff(T) dependence has been found. A comparison of the theoretical results with experimental magnetization data in Meissner and mixed states of YBCO nanopowders has been done. The presence of nonlinear and nonlocal effects in vortex current distribution is clearly visible. The obtained results are important for the description
From magnetically doped topological insulator to the quantum anomalous Hall effect
Institute of Scientific and Technical Information of China (English)
He Ke; Ma Xu-Cun; Chen Xi; Lü Li; Wang Ya-Yu; Xue Qi-Kun
2013-01-01
Quantum Hall effect (QHE),as a class of quantum phenomena that occur in macroscopic scale,is one of the most important topics in condensed matter physics.It has long been expected that QHE may occur without Landau levels so that neither extemal magnetic field nor high sample mobility is required for its study and application.Such a QHE free of Landau levels,can appear in topological insulators (TIs) with ferromagnetism as the quantized version of the anomalous Hall effect,i.e.,quantum anomalous Hall (QAH) effect.Here we review our recent work on experimental realization of the QAH effect in magnetically doped TIs.With molecular beam epitaxy,we prepare thin films of Cr-doped (Bi,Sb)2Te3 TIs with wellcontrolled chemical potential and long-range ferromagnetic order that can survive the insulating phase.In such thin films,we eventually observed the quantization of the Hall resistance at h/e2 at zero field,accompanied by a considerable drop in the longitudinal resistance.Under a strong magnetic field,the longitudinal resistance vanishes,whereas the Hall resistance remains at the quantized value.The realization of the QAH effect provides a foundation for many other novel quantum phenomena predicted in TIs,and opens a route to practical applications of quantum Hall physics in low-power-consumption electronics.
Desai, Rucha; Upadhyay, R. V.
2014-12-01
Magnetorheological properties are experimentally investigated in aqueous magnetic fluid containing spherical silica nanoparticles. A bi-dispersed system is prepared using aqueous suspension of silica nanoparticles and aqueous magnetic fluid. Both these fluids exhibit Newtonian viscosity with nominal values of 1.3 and 5.8 mPa\\cdot s at 20 °C. Three different samples are prepared by varying silica and magnetic fluid concentrations and keeping the total volume constant. The addition of silica nanoparticles leads to enhancement of the magnetic field induced viscosity up to the order 107 Pa\\cdot s. The magnetic field induced viscosity is analyzed using the structural viscosity model. Magnetic field induced static and dynamic yield stress values to reveal the existence of field induced clustering. An attempt is made to explain this yielding behavior using chain-like and micromechanical models. It is found that high silica fraction leads to the formation of chain-like structure. At low silica fraction, chains overlap and result into layer aggregates, which are responsible for the anomalous increase in the magnetorheological properties. This is further confirmed using magnetic field microscopic chain formations.
Soft gamma-ray repeaters and anomalous X-ray pulsars as highly magnetized white dwarfs
Mukhopadhyay, Banibrata
2016-01-01
We explore the possibility that soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are powered by highly magnetized white dwarfs (B-WDs). We take a sample of SGRs and AXPs and provide the possible parameter space in mass, radius, and surface magnetic field based on their observed properties (period and its derivative) and the assumption that these sources obey the mass-radius relation derived for the B-WDs. The radius and magnetic field of B-WDs are adequate to explain energies in SGRs/AXPs as the rotationally powered energy. In addition, B-WDs also adequately explain the perplexing radio transient GCRT J1745-3009 as a white dwarf pulsar. Note that the radius and magnetic fields of B-WDs are neither extreme (unlike of highly magnetized neutron stars) nor ordinary (unlike of magnetized white dwarfs, yet following the Chandrasekhar's mass-radius relation (C-WDs)). In order to explain SGRs/AXPs, while the highly magnetized neutron stars require an extra, observationally not well established yet, ...
Soft gamma-ray repeaters and anomalous X-ray pulsars as highly magnetized white dwarfs
Mukhopadhyay, Banibrata; Rao, A. R.
2016-05-01
We explore the possibility that soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are powered by highly magnetized white dwarfs (B-WDs). We take a sample of SGRs and AXPs and provide the possible parameter space in mass, radius, and surface magnetic field based on their observed properties (period and its derivative) and the assumption that these sources obey the mass-radius relation derived for the B-WDs. The radius and magnetic field of B-WDs are adequate to explain energies in SGRs/AXPs as the rotationally powered energy. In addition, B-WDs also adequately explain the perplexing radio transient GCRT J1745-3009 as a white dwarf pulsar. Note that the radius and magnetic fields of B-WDs are neither extreme (unlike of highly magnetized neutron stars) nor ordinary (unlike of magnetized white dwarfs, yet following the Chandrasekhar's mass-radius relation (C-WDs)). In order to explain SGRs/AXPs, while the highly magnetized neutron stars require an extra, observationally not well established yet, source of energy, the C-WDs predict large ultra-violet luminosity which is observationally constrained from a strict upper limit. Finally, we provide a set of basic differences between the magnetar and B-WD hypotheses for SGRs/AXPs.
Large enhancement of magnetic moment in L1(0) ordered FePt thin films by Nd substitutional doping
Energy Technology Data Exchange (ETDEWEB)
Xu, D. B.; Sun, C J; Chen, J. S.; Heald, S M; Sanyal, B.; Rosenberg, R. A.; Zhou, T. J.; Chow, G. M.
2015-07-01
We studied L1(0) ordered Fe50Pt50-xNdx alloy films, which showed a large enhancement (similar to 18.4% at room temperature and similar to 11.7% at 10 K) of magnetic moment with 6 atomic % of Nd. Analysis of the x-ray magnetic circular dichroism spectra at the Fe L-3,L-2 edges and Nd M-5,M-4 edges in Fe50Pt44Nd6 films indicated a significant contribution of the Nd orbital moment. The origin of the large enhancement of magnetic moment was attributed to the effect of ferromagnetic coupling of the total magnetic moments between Fe and Nd. Density functional theory based first principles calculations supported the experimental observations of increasing moment due to Nd substitution of Pt.
Research Update: Plentiful magnetic moments in oxygen deficient SrTiO{sub 3}
Energy Technology Data Exchange (ETDEWEB)
Lopez-Bezanilla, Alejandro, E-mail: alejandrolb@gmail.com [Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439 (United States); Ganesh, P. [Center for Nanophase Materials Science, Oak Ridge National Laboratory, One Bethel Valley Road, Tennessee 37831 (United States); Littlewood, Peter B. [Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439 (United States); James Franck Institute, University of Chicago, Chicago, Illinois 60637 (United States)
2015-10-01
Correlated band theory is employed to investigate the magnetic and electronic properties of different arrangements of oxygen di- and tri-vacancy clusters in SrTiO{sub 3}. Hole and electron doping of oxygen deficient SrTiO{sub 3} yields various degrees of magnetization as a result of the interaction between localized magnetic moments at the defect sites. Different kinds of Ti atomic orbital hybridization are described as a function of the doping level and defect geometry. We find that magnetism in SrTiO{sub 3−δ} is sensitive to the arrangement of neighbouring vacancy sites, charge carrier density, and vacancy-vacancy interaction. Permanent magnetic moments in the absence of vacancy doping electrons are observed. Our description of the charged clusters of oxygen vacancies widens the previous descriptions of mono- and multi-vacancies and points out the importance of the controlled formation at the atomic level of defects for the realization of transition metal oxide based devices with a desirable magnetic performance.
Plentiful magnetic moments in oxygen deficient SrTiO_{3}.
Energy Technology Data Exchange (ETDEWEB)
Lopez Bezanilla, Alejandro; Ganesh, P.; Littlewood, Peter B.
2015-10-01
Correlated band theory is employed to investigate the magnetic and electronic properties of different arrangements of oxygen di- and tri-vacancy clusters in SrTiO_{3}. Hole and electron doping of oxygen deficient SrTiO_{3} yields various degrees of magnetization as a result of the interaction between localized magnetic moments at the defected sites. Different kinds of Ti atomic orbital hybridization are described as a function of the doping level and defect geometry. We find that magnetism in SrTiO_{3}-d is sensitive to the arrangement of neighbouring vacancy sites, charge carrier density, and vacancy-vacancy interaction. Permanent magnetic moments in the absence of vacancy doping electrons are observed. Our description of the charged clusters of oxygen vacancies widens the previous descriptions of mono and multi-vacancies and points out the importance of the controlled formation at the atomic level of defects for the realization of transition metal oxide based devices with a desirable magnetic performance.
Spontaneous magnetization in high-density quark matter
International Nuclear Information System (INIS)
It is shown that spontaneous magnetization occurs due to the anomalous magnetic moments of quarks in high-density quark matter under the tensor-type four-point interaction. The spin polarized condensate for each flavor of quark appears at high baryon density, which leads to the spontaneous magnetization due to the anomalous magnetic moments of quarks. The implications for the strong magnetic field in compact stars is discussed
Spontaneous magnetization in high-density quark matter
DEFF Research Database (Denmark)
Tsue, Yasuhiko; da Providência, João; Providência, Constanca;
2015-01-01
It is shown that spontaneous magnetization occurs due to the anomalous magnetic moments of quarks in high-density quark matter under the tensor-type four-point interaction. The spin polarized condensate for each flavor of quark appears at high baryon density, which leads to the spontaneous...... magnetization due to the anomalous magnetic moments of quarks. The implications for the strong magnetic field in compact stars is discussed....
Magnetic moments in a helical edge can make weak correlations seem strong
Väyrynen, Jukka I.; Geissler, Florian; Glazman, Leonid I.
2016-06-01
We study the effect of localized magnetic moments on the conductance of a helical edge. Interaction with a local moment is an effective backscattering mechanism for the edge electrons. We evaluate the resulting differential conductance as a function of temperature T and applied bias V for any value of V /T . Backscattering off magnetic moments, combined with the weak repulsion between the edge electrons, results in a power-law temperature and voltage dependence of the conductance; the corresponding small positive exponent is indicative of insulating behavior. Local moments may naturally appear due to charge disorder in a narrow-gap semiconductor. Our results provide an alternative interpretation of the recent experiment by Li et al. [Phys. Rev. Lett. 115, 136804 (2015)], 10.1103/PhysRevLett.115.136804 where a power-law suppression of the conductance was attributed to strong electron repulsion within the edge, with the value of Luttinger-liquid parameter K fine tuned close to 1 /4 .
In-gas-cell laser spectroscopy for magnetic dipole moment of $^{199}$Pt toward $N=$ 126
Hirayama, Y; Watanabe, Y X; Jeong, S C; Jung, H S; Kakiguchi, Y; Kimura, S; Moon, J Y; Oyaizu, M; Park, J H; Schury, P; Wada, M; Miyatake, H
2016-01-01
Magnetic dipole moment and mean-square charge radius of $^{199}$Pt ($I^{\\pi}=$ 5/2$^-$) have been evaluated for the first time from the investigation of the hyperfine splitting of the $\\lambda_1=$ 248.792 nm transition by in-gas-cell laser ionization spectroscopy. Neutron-rich nucleus $^{199}$Pt was produced by multi-nucleon transfer reaction at the KISS where the nuclear spectroscopy in the vicinity of $N=$ 126 is planed from the aspect of an astrophysical interest as well as the nuclear structure. Measured magnetic dipole moment $+$0.63(13)$\\mu_{\\rm N}$ is consistent with the systematics of those of nuclei with $I^{\\pi}=$ 5/2$^-$. The deformation parameter $|^{1/2}|$ evaluated from the isotope shift indicates the gradual shape change to spherical shape of platinum isotopes with increasing neutron number toward $N=$ 126.
Li, J; Hu, J N; Ring, P; Meng, J
2013-01-01
Using the relativistic point-coupling model with density functional PC-PK1, the magnetic moments of the nuclei $^{207}$Pb, $^{209}$Pb, $^{207}$Tl and $^{209}$Bi with a $jj$ closed-shell core $^{208}$Pb are studied on the basis of relativistic mean field (RMF) theory. The corresponding time-odd fields, the one-pion exchange currents, and the first- and second-order corrections are taken into account. The present relativistic results reproduce the data well. The relative deviation between theory and experiment for these four nuclei is 6.1% for the relativistic calculations and somewhat smaller than the value of 13.2% found in earlier non-relativistic investigations. It turns out that the $\\pi$ meson is important for the description of magnetic moments, first by means of one-pion exchange currents and second by the residual interaction provided by the $\\pi$ exchange.
Nuclear magnetic moment measurements through hyperfine interactions in highly stripped ions
International Nuclear Information System (INIS)
Time-differential magnetic moment measurements on the first-excited Isup(π)=2+ states in 20Ne and 24Mg with mean lives of 1.0 and 2.1 ps, respectively are described. The lifetime of the latter state was determined simultaneously. A special detection geometry was designed to improve the experimental γ-ray anisotropy measured with finite-size detectors. For 20Ne also a time-integral measurement with charge-state separation was performed. The necessary electronics circuitry built to perform these complicated measurements and the plunger assembly with laser interferometer are also described. A magnetic moment measurement of 22Ne(21+) with tau=5.0 ps and transient field measurements at low and high recoil velocities are reported. A discussion of possible extensions of the techniques are given. (Auth.)
Orbital magnetic moment and extrinsic spin Hall effect for iron impurities in gold
Shick, Alexander B.; Kolorenč, Jindřich; Janiš, Václav; Lichtenstein, Alexander I.
2011-09-01
We report electronic structure calculations of an iron impurity in a gold host. The spin, orbital, and dipole magnetic moments were investigated using the local density approximation (LDA) + U correlated band theory. We show that the around-mean-field LDA + U reproduces the x-ray magnetic circular dichroism (XMCD) experimental data well and does not lead to the formation of a large orbital moment on the Fe atom. Furthermore, exact diagonalization of the multiorbital Anderson impurity model with the full Coulomb interaction matrix and the spin-orbit coupling is performed in order to estimate the spin Hall angle. The obtained value γS≈0.025 suggests that there is no giant extrinsic spin Hall effect due to scattering on iron impurities in gold.
Vortices and domain walls in a Chern-Simons theory with magnetic moment interactions
International Nuclear Information System (INIS)
We study the structure and properties of vortices in a recently proposed Abelian Maxwell-Chern-Simons model in 2+1 dimensions. The model which is described by a gauge field interacting with a complex scalar field includes two parity- and time-violating terms: the Chern-Simons and the anomalous magnetic terms. Self-dual relativistic vortices are discussed in detail. We also find one-dimensional soliton solutions of the domain wall type. The vortices are correctly described by the domain wall solutions in the large flux limit. copyright 1997 The American Physical Society
Rotating effects on the Landau quantization for an atom with a magnetic quadrupole moment
Fonseca, I C
2016-01-01
Based on the single particle approximation [V. F. Dmitriev {\\it et al}, Phys. Rev. C {\\bf50}, 2358 (1994), C.-C. Chen, Phys. Rev. A {\\bf51}, 2611 (1995)], the Landau quantization associated with an atom with a magnetic quadrupole moment is introduced, and then, rotating effects on this analogue of the Landau quantization is investigated. It is shown that rotating effects can modify the cyclotron frequency and breaks the degeneracy of the analogue of the Landau levels.
Masses and magnetic moments of ground-state baryons in covariant baryon chiral perturbation theory
Geng, L S; Alvarez-Ruso, L; Vicente-Vacas, M J
2012-01-01
We report on some recent developments in our understanding of the light-quark mass dependence and the SU(3) flavor symmetry breaking corrections to the magnetic moments of the ground-state baryons in a covariant formulation of baryon chiral perturbation theory, the so-called EOMS formulation. We show that this covariant ChPT exhibits some promising features compared to its heavy-baryon and infrared counterparts.
Nuclear magnetic moments and the spin-orbit current in the relativistic mean field theory
International Nuclear Information System (INIS)
The Dirac magnetic moments in the relativistic mean field theory are affected not only by the effective mass, but also by the spin-orbit current related to the spin-orbit force through the continuity equation. Previous arguments on the cancellation of the effective-mass effect in nuclear matter are not simply applied to finite nuclei to obtain the Schmidt values. Effects of the spin-orbit current on (e, e') response functions are also mentioned. (orig.)
Deák, A.; E. Simon; Balogh, L.; Szunyogh, L.; dos Santos Dias, M.; Staunton, J. B.
2014-01-01
We develop a self-consistent relativistic disordered local moment (RDLM) scheme aimed at describing finite-temperature magnetism of itinerant metals from first principles. Our implementation in terms of the Korringa-Kohn-Rostoker multiple-scattering theory and the coherent potential approximation allows us to relate the orientational distribution of the spins to the electronic structure, thus a self-consistent treatment of the distribution is possible. We present applications for bulk bcc Fe,...
Silenko, A. J.
2013-01-01
A buildup of the vertical polarization in the resonant electric dipole moment (EDM) experiment [Y. F. Orlov, W. M. Morse, and Y. K. Semertzidis, Phys. Rev. Lett. 96, 214802 (2006)] is affected by a horizontal electric field in the particle rest frame oscillating at a resonant frequency. This field is defined by the Lorentz transformation of an oscillating longitudinal electric field and a uniform vertical magnetic one. The effect of a longitudinal electric field is significant, while the cont...
Rotating effects on the Landau quantization for an atom with a magnetic quadrupole moment.
Fonseca, I C; Bakke, K
2016-01-01
Based on the single particle approximation [Dmitriev et al., Phys. Rev. C 50, 2358 (1994) and C.-C. Chen, Phys. Rev. A 51, 2611 (1995)], the Landau quantization associated with an atom with a magnetic quadrupole moment is introduced, and then, rotating effects on this analogue of the Landau quantization is investigated. It is shown that rotating effects can modify the cyclotron frequency and breaks the degeneracy of the analogue of the Landau levels.
Rotating effects on the Landau quantization for an atom with a magnetic quadrupole moment
Energy Technology Data Exchange (ETDEWEB)
Fonseca, I. C.; Bakke, K., E-mail: kbakke@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, João Pessoa, PB 58051-970 (Brazil)
2016-01-07
Based on the single particle approximation [Dmitriev et al., Phys. Rev. C 50, 2358 (1994) and C.-C. Chen, Phys. Rev. A 51, 2611 (1995)], the Landau quantization associated with an atom with a magnetic quadrupole moment is introduced, and then, rotating effects on this analogue of the Landau quantization is investigated. It is shown that rotating effects can modify the cyclotron frequency and breaks the degeneracy of the analogue of the Landau levels.
Magnetic moments in present relativistic nuclear theories: a mean-field problem
International Nuclear Information System (INIS)
We show that the magnetic moments of LS closed shell nuclei plus or minus one nucleon derived from non-relativistic Hartree-Fock mean-fields are as bad as those obtained in relativistic approaches of nuclear structure. Deviations with respect to more complete results in both cases are ascribed to the mean-field approximation which neglects some degrees of freedom in the nucleus description. 18 refs
Directory of Open Access Journals (Sweden)
Samanbir S Kalirai
Full Text Available There is a good deal of published evidence that indicates that all magnetosomes within a single cell of a magnetotactic bacterium are magnetically oriented in the same direction so that they form a single magnetic dipole believed to assist navigation of the cell to optimal environments for their growth and survival. Some cells of the cultured magnetotactic bacterium Magnetovibrio blakemorei strain MV-1 are known to have relatively wide gaps between groups of magnetosomes that do not seem to interfere with the larger, overall linear arrangement of the magnetosomes along the long axis of the cell. We determined the magnetic orientation of the magnetosomes in individual cells of this bacterium using Fe 2p X-ray magnetic circular dichroism (XMCD spectra measured with scanning transmission X-ray microscopy (STXM. We observed a significant number of cases in which there are sub-chains in a single cell, with spatial gaps between them, in which one or more sub-chains are magnetically polarized opposite to other sub-chains in the same cell. These occur with an estimated frequency of 4.0±0.2%, based on a sample size of 150 cells. We propose possible explanations for these anomalous cases which shed insight into the mechanisms of chain formation and magnetic alignment.
LaCoO3 (LCO) - Dramatic changes in Magnetic Moment in fields to 500T
Lee, Y.; Harmon, B. N.
LCO has attracted great attention over the years (>2000 publications) because of its unusual magnetic properties; although in its ground state at low temperatures it is non-magnetic. A recent experiment[1] in pulsed fields to 500T showed a moment of ~1.3μB above 140T, and above ~270T the magnetization rises, reaching ~3.8μB by 500T. We have performed first principles DFT calculations for LCO in high fields. Our earlier calculations[2] explained the importance of a small rhombohedral distortion in the ground state that leads to a suppression of the 1.3μB moment for fields below ~140T. By allowing fairly large atomic displacements in high fields, moments of ~4μB are predicted. This work was supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences, Materials Science and Engineering Division under Contract No. DE-AC02-07CH11358.
Magnetic dipole moments of High-K isomeric states in Hf isotopes
Walters, W; Nishimura, K; Bingham, C R
2007-01-01
It is proposed to make precision measurements of the magnetic moments of 5 multi-quasi-particle K-isomers in Hf nuclei by the Nuclear Magnetic Resonance of Oriented Nuclei (NMR/ON) technique using the NICOLE on-line nuclear orientation facility and exploiting the unique HfF$_{3}$ beams recently available at ISOLDE. Results will be used to extract single-particle and collective g-factors of the isomeric states and their excitations and to shed new light on their structure.
Probing the Pu4 + magnetic moment in PuF4 with 19F NMR spectroscopy
Capan, Cigdem; Dempsey, Richard J.; Sinkov, Sergey; McNamara, Bruce K.; Cho, Herman
2016-06-01
The magnetic fields produced by Pu4 + centers have been measured by 19F NMR spectroscopy to elucidate the Pu-F electronic interactions in polycrystalline PuF4. Spectra acquired at applied fields of 2.35 and 7.05 T reveal a linear scaling of the 19F line shape. A model is presented that treats the line broadening and shifts as due to dipolar fields produced by Pu valence electrons in localized noninteracting orbitals. Alternative explanations for the observed line shape involving covalent Pu-F bonding, superexchange interactions, and electronic configurations with enhanced magnetic moments are considered.
Chiral structures and tunable magnetic moments in 3d transition metal doped Pt6 clusters
Institute of Scientific and Technical Information of China (English)
Zhang Xiu-Rong; Yang Xing; Ding Xun-Lei
2012-01-01
The structural,electronic,and magnetic properties of transition metal doped platinum clusters MPt6 (M＝Sc,Ti,V,Cr,Mn,Fe,Co,Ni,Cu,and Zn) are systematically studied by using the relativistic all-electron density functional theory with the generalized gradient approximation. Most of the doped clusters show larger binding energies than the pure Pt7 cluster,which indicates that the doping of the transition metal atom can stabilize the pure platinum cluster.The results of the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gaps suggest that the doped clusters can have higher chemical activities than the pure Pt7 cluster.The magnetism calculations demonstrate that the variation range of the magnetic moments of the MPt6 clusters is from 0 μB to 7 μB,revealing that the MPt6 clusters have potential utility in designing new spintronic nanomaterials with tunable magnetic properties.
Magnetic excitations and anomalous spin-wave broadening in multiferroic FeV2O4
Energy Technology Data Exchange (ETDEWEB)
Zhang, Qiang [Ames Laboratory; Ramazanoglu, Mehmet [Ames Laboratory; Chi, Songxue [Oak Ridge National Laboratory; Liu, Yong [Ames Laboratory; Lograsso, Thomas A. [Ames Laboratory; Vaknin, David [Ames Laboratory
2014-06-01
We report on the different roles of two orbital-active Fe2+ at the A site and V3+ at the B site in the magnetic excitations and on the anomalous spin-wave broadening in FeV2O4. FeV2O4 exhibits three structural transitions and successive paramagnetic (PM)–collinear ferrimagnetic (CFI)–noncollinear ferrimagnetic (NCFI)/ferroelectric transitions. The high-temperature tetragonal/PM–orthorhombic/CFI transition is accompanied by the appearance of a large energy gap in the magnetic excitations due to strong spin-orbit-coupling-induced anisotropy at the Fe2+ site. While there is no measurable increase in the energy gap from the orbital ordering of V3+ at the orthorhombic/CFI–tetragonal/NCFI transition, anomalous spin-wave broadening is observed in the orthorhombic/CFI state due to V3+ spin fluctuations at the B site. The spin-wave broadening is also observed at the zone boundary without softening in the NCFI/ferroelectric phase, which is discussed in terms of magnon-phonon coupling. Our study also indicates that the Fe2+ spins without the frustration at the A site may not play an important role in inducing ferroelectricity in the tetragonal/NCFI phase of FeV2O4.
Quantum anomalous Hall effect in atomic crystal layers from in-plane magnetization
Ren, Yafei; Zeng, Junjie; Deng, Xinzhou; Yang, Fei; Pan, Hui; Qiao, Zhenhua
2016-08-01
We theoretically demonstrate that with in-plane magnetization, the quantum anomalous Hall effect (QAHE) can be realized in two-dimensional atomic crystal layers with preserved inversion symmetry but broken out-of-plane mirror reflection symmetry. By taking the honeycomb lattice system as an example, we find that the low-buckled structure satisfying the symmetry criteria is crucial to induce QAHE. The topologically nontrivial bulk gap carrying a Chern number of C =±1 opens in the vicinity of the saddle points M , where the band dispersion exhibits strong anisotropy. We further show that the QAHE with electrically tunable Chern number can be achieved in Bernal-stacked multilayer systems, and the applied interlayer potential differences can dramatically decrease the critical magnetization to make the QAHE experimentally feasible.
A magnetic reconnection mechanism for the generation of anomalous cosmic rays
Drake, James; Opher, Merav; Swisdak, Marc; Chamoun, Jacob
The recent observations of the anomalous cosmic ray (ACR) energy spectrum as Voyagers 1 and 2 crossed the heliospheric termination shock have called into question the conventional shock source of these energetic particles. We suggest that the sectored heliospheric magnetic field, which results from the flapping of the heliospheric current sheet, piles up as it approaches the heliopause, narrowing the current sheets that separate the sectors and triggering the onset of collisionless magnetic reconnection. Particle-in-cell simulations reveal that the current layers break up into a turbulent bath of magnetic islands that merge to release a large fraction of the energy in the sectored magnetic field. Most of the magnetic energy goes into energetic ions with significant but smaller amounts of energy going into electrons. The dominant acceleration mechanism is through reflection in contracting islands, a first-order Fermi mechanism. Particle energy gain is regulated by the approach to the marginal firehose condition. The ACR differ-ential energy spectrum for all of the ion species takes the form of a power law with a spectral index slightly above 1.5, which is consistent with observations.
Rashba Interaction and Local Magnetic Moments in a Graphene-BN Heterostructure Intercalated with Au
O'Farrell, E. C. T.; Tan, J. Y.; Yeo, Y.; Koon, G. K. W.; Ã-zyilmaz, B.; Watanabe, K.; Taniguchi, T.
2016-08-01
We intercalate a van der Waals heterostructure of graphene and hexagonal boron nitride with Au, by encapsulation, and show that the Au at the interface is two dimensional. Charge transfer upon current annealing indicates the redistribution of the Au and induces splitting of the graphene band structure. The effect of an in-plane magnetic field confirms that the splitting is due to spin splitting and that the spin polarization is in the plane, characteristic of a Rashba interaction with a magnitude of approximately 25 meV. Consistent with the presence of an intrinsic interfacial electric field we show that the splitting can be enhanced by an applied displacement field in dual gated samples. A giant negative magnetoresistance, up to 75%, and a field induced anomalous Hall effect at magnetic fields effects persist close to room temperature.
van Rijssel, Jozef; Kuipers, Bonny W M; Erne, Ben
2015-01-01
High-frequency applications of magnetic nanoparticles, such as therapeutic hyperthermia and magnetic particle imaging, are sensitive to nanoparticle size and dipole moment. Usually, it is assumed that magnetic nanoparticles with a log-normal distribution of the physical size also have a log-normal d
Magnetic and Distribution of Magnetic Moments in Amorphous Fe89.7 P10.3 Alloy Nanowire Arrays
International Nuclear Information System (INIS)
Binary amorphous Fe89.7P10.3 alloy nanowire arrays in diameter of about 40nm and length of about 3 μm have been fabricated in an anodic aluminium oxide template by electrodeposition. Magnetic properties of the samples are investigated by mean of vibrating sample magnetometer, transmission Mössbauer spectroscopy and conversion electron Mössbauer spectroscopy at room temperature. It is found that the nanowire arrays have obvious perpendicular magnetic anisotropy and are ferromagnetic at room temperature, with its Mössbauer spectra consisting of six broad lines. The average angles between the Fe magnetic moment and the wire axis are about 14° inside and 28° at the end of the amorphous Fe89.7P10.3 alloy nanowire arrays, respectively. The magnetic behaviour is decided by the shape anisotropy and the dipolar interaction between wires. In addition, the magnetic moments distribution is theoretically demonstrated by using the symmetric fanning mechanism of the spheres chain model
Magnetic and Distribution of Magnetic Moments in Amorphous Fe89.7P10.3Alloy Nanowire Arrays
Institute of Scientific and Technical Information of China (English)
SHI Hui-Gang; XUE De-Sheng
2008-01-01
Binary amorphous Fe89.7P10.3 alloy nanowire arrays in diameter of about 40nm and length of about 3μm have been fabricated in an anodic aluminium oxide template by electrodeposition.Magnetic properties of the samples are investigated by mean of vibrating sample magnetometer,transmission M(o)ssbauer spectroscopy and conversion electron M(o)ssbauer spectroscopy at room temperature.It is found that the nanowire arrays have obvious perpendicular magnetic anisotropy,and are ferromagnetic at room temperature,with its M(o)ssbauer spectra consisting of six broad lines.The average anglas between the Fe magnetic moment and the wire axis are about 14°inside and 28°at the end of the amorphous Fe89.7P10.3 alloy nanowire arrays,respectively.The magnetic behaviour is decided by the shape anisotropy and the dipolar interaction between wires.In addition,the magnetic moments distribution is theoretically demonstrated by using the symmetric fanning mechanism of the spheres chain model.
Remote sensing of the magnetic moment of uranus: predictions for voyager.
Hill, T W; Dessler, A J
1985-03-22
Power is supplied to a planet's magnetosphere from the kinetic energy of planetary spin and the energy flux of the impinging solar wind. A fraction of this power is available to drive numerous observable phenomena, such as polar auroras and planetary radio emissions. In this report our present understanding of these power transfer mechanisms is applied to Uranus to make specific predictions of the detectability of radio and auroral emissions by the planetary radio astronomy (PRA) and ultraviolet spectrometer (UVS) instruments aboard the Voyager spacecraft before its encounter with Uranus at the end of January 1986. The power available for these two phenomena is (among other factors) a function of the magnetic moment of Uranus. The date of earliest detectability also depends on whether the predominant power source for the magnetosphere is planetary spin or solar wind. The magnetic moment of Uranus is derived for each power source as a function of the date of first detection of radio emissions by the PRA instrument or auroral emissions by the UVS instrument. If we accept the interpretation of ultraviolet observations now available from the Earth-orbiting International Ultraviolet Explorer satellite, Uranus has a surface magnetic field of at least 0.6 gauss, and more probably several gauss, making it the largest or second-largest planetary magnetic field in the solar system. PMID:17777779
Switchable magnetic moment in cobalt-doped graphene bilayer on Cu(111): An ab initio study
Souza, Everson S.; Scopel, Wanderlã L.; Miwa, R. H.
2016-06-01
In this work, we have performed an ab initio theoretical investigation of substitutional cobalt atoms in the graphene bilayer supported on the Cu(111) surface (Co/GBL/Cu). Initially, we examined the separated systems, namely, graphene bilayer adsorbed on Cu(111) (GBL/Cu) and a free standing Co-doped GBL (Co/GBL). In the former system, the GBL becomes n -type doped, where we map the net electronic charge density distribution along the GBL-Cu(111) interface. The substitutional Co atom in Co/GBL lies between the graphene layers, and present a net magnetic moment mostly due to the unpaired Co-3 dz2 electrons. In Co/GBL/Cu, we found that the Cu(111) substrate rules (i) the energetic stability, and (ii) the magnetic properties of substitutional Co atoms in the graphene bilayer. In (i), the substitutional Co atom becomes energetically more stable lying on the GBL surface, and in (ii), the magnetic moment of Co/GBL has been quenched due to the Cu(111) → Co/GBL electronic charge transfer. We verify that such a charge transfer can be tuned upon the application of an external electric field, and thus mediated by a suitable change on the electronic occupation of the Co-dz2 orbitals, we found a way to switch-on and -off the magnetization of the Co-doped GBL adsorbed on the Cu(111) surface.
International Nuclear Information System (INIS)
We obtain bounds on the anomalous magnetic and electric dipole moments of the tau-neutrino through the reaction e+e-→ννγ at the Z1-pole in the framework of a Left-Right symmetric model and a class of E6 inspired models with an additional neutral vector boson Zθ. We use the data collected by the L3 Collaboration at LEP. For the parameters of the E6 model we consider the mixing angle θE6=37.8 deg. and MZθ=7MZ1. We find that our bounds are of the same order of magnitude as those obtained in other extensions of the standard model
Energy Technology Data Exchange (ETDEWEB)
Muraca, Diego, E-mail: dmuraca@ifi.unicamp.br; Siervo, Abner de; Pirota, Kleber R. [Universidade Estadual de Campinas (UNICAMP), Instituto de Fsica Gleb Wataghin (IFGW) (Brazil)
2013-01-15
In this study, the correlation between magnetic, structure, and electronic properties of Ag-Fe{sub 3}O{sub 4} hetero nanostructures are presented. These nanostructures were prepared using a two-step new chemical approach. Three different nanoparticle systems with different Ag concentrations have been prepared and characterized using high resolution transmission electron microscopy, dc magnetization (magnetization and coercive field as a function of temperature), X-ray absorption near edge spectroscopy, and magnetic circular dichroism studies (XMCD). From the correlation between XMCD and dc magnetic measurements (Verwey transition) the presence of non-stoichiometric magnetite in Ag-Fe{sub 3}O{sub 4} nanoparticle systems was confirmed. From the spin and orbital contribution to the total magnetic moment, we conclude that the sample with less Ag seeds particle concentration presents a non-quenched orbital contribution. These phenomena were analyzed based on the actual models and correlated with dc magnetic properties. From these, we conclude that the enhancement on the orbital contribution increases the spin orbital interaction, also increasing the magnetocrystalline anisotropy reflected on the dc magnetic properties.
Energy Technology Data Exchange (ETDEWEB)
Rijssel, Jos van; Kuipers, Bonny W.M.; Erné, Ben H., E-mail: B.H.Erne@uu.nl
2015-04-15
High-frequency applications of magnetic nanoparticles, such as therapeutic hyperthermia and magnetic particle imaging, are sensitive to nanoparticle size and dipole moment. Usually, it is assumed that magnetic nanoparticles with a log-normal distribution of the physical size also have a log-normal distribution of the magnetic dipole moment. Here, we test this assumption for different types of superparamagnetic iron oxide nanoparticles in the 5–20 nm range, by multimodal fitting of magnetization curves using the MINORIM inversion method. The particles are studied while in dilute colloidal dispersion in a liquid, thereby preventing hysteresis and diminishing the effects of magnetic anisotropy on the interpretation of the magnetization curves. For two different types of well crystallized particles, the magnetic distribution is indeed log-normal, as expected from the physical size distribution. However, two other types of particles, with twinning defects or inhomogeneous oxide phases, are found to have a bimodal magnetic distribution. Our qualitative explanation is that relatively low fields are sufficient to begin aligning the particles in the liquid on the basis of their net dipole moment, whereas higher fields are required to align the smaller domains or less magnetic phases inside the particles. - Highlights: • Multimodal fits of dilute ferrofluids reveal when the particles are multidomain. • No a priori shape of the distribution is assumed by the MINORIM inversion method. • Well crystallized particles have log-normal TEM and magnetic size distributions. • Defective particles can combine a monomodal size and a bimodal dipole moment.
Nd-doped ZnO monolayer: High Curie temperature and large magnetic moment
Tan, Changlong; Sun, Dan; Zhou, Long; Tian, Xiaohua; Huang, Yuewu
2016-10-01
We performed first-principles calculations within density-functional theory to study the structural, electronic, and magnetic properties of Nd-doped ZnO monolayer. The calculated results reveal that Nd-doped ZnO monolayer exhibits stable room temperature ferromagnetism with a large saturation magnetic moment of 3.99 μB per unit in ZnO monolayer. The magnetic property is contributed to the localized f sates of Nd atoms. When two Zn atoms are substituted by two Nd dopants, they tend to form ferromagnetic (FM) coupling and the estimated Curie temperature is higher than room temperature. More interesting, the impurity bands appear within the band gap of ZnO monolayer due to the introduction of Nd dopant. Our results may provide a reference for modifying the material property of ZnO monolayer and are promising as nanoscale building block in spintronic devices.
Magnetic moment of $X_Q$ state with $J^{PC}=1^{+\\pm}$ in light cone QCD sum rules
Agamaliev, A K; Savcı, M
2016-01-01
The magnetic moments of the recently observed resonance $X_b(5568)$ by DO Collaboration and its partner with charm quark are calculated in the framework of the light cone QCD sum rules, by assuming that these resonances are represented as tetra--quark states with quantum numbers $J^{PC}=1^{+\\pm}$. The magnetic moment can play critical role in determination of the quantum numbers, as well as giving useful information about the inner structure of these mesons.
Aliev, T M
2015-01-01
The magnetic moment of the $\\Lambda \\to \\Sigma^0$ transition between negative parity, baryons is calculated in framework of the QCD sum rules approach, using the general form of the interpolating currents. The pollution arising from the positive--to--positive, and positive to negative parity baryons are eliminated by constructing the sum rules for different Lorentz structures. Nonzero value of the considered magnetic moment can be attributed to the violation of the $SU(3)$ symmetry.
Itinerancy-enhanced quantum fluctuation of magnetic moments in iron-based superconductors.
Tam, Yu-Ting; Yao, Dao-Xin; Ku, Wei
2015-09-11
We investigate the influence of itinerant carriers on the dynamics and fluctuation of local moments in Fe-based superconductors, via linear spin-wave analysis of a spin-fermion model containing both itinerant and local degrees of freedom. Surprisingly, against the common lore, instead of enhancing the (π,0) order, itinerant carriers with well-nested Fermi surfaces are found to induce a significant amount of spatial and temporal quantum fluctuation that leads to the observed small ordered moment. Interestingly, the underlying mechanism is shown to be an intrapocket nesting-associated long-range coupling rather than the previously believed ferromagnetic double-exchange effect. This challenges the validity of ferromagnetically compensated first-neighbor coupling reported from short-range fitting to the experimental dispersion, which turns out to result instead from the ferro-orbital order that is also found instrumental in stabilizing the magnetic order. PMID:26406850
Realizing high magnetic moments in fcc Fe nanoparticles through atomic structure stretch.
Baker, S H; Roy, M; Thornton, S C; Binns, C
2012-05-01
We describe the realization of a high moment state in fcc Fe nanoparticles through a controlled change in their atomic structure. Embedding Fe nanoparticles in a Cu(1-x)Au(x) matrix causes their atomic structure to switch from bcc to fcc. Extended x-ray absorption fine structure (EXAFS) measurements show that the structure in both the matrix and the Fe nanoparticles expands as the amount of Au in the matrix is increased, with the data indicating a tetragonal stretch in the Fe nanoparticles. The samples were prepared directly from the gas phase by co-deposition, using a gas aggregation source and MBE-type sources respectively for the nanoparticle and matrix materials. The structure change in the Fe nanoparticles is accompanied by a sharp increase in atomic magnetic moment, ultimately to values of ~2.5 ± 0.3 μ(B)/atom .
Alling, B.; Körmann, F.; Grabowski, B.; Glensk, A.; Abrikosov, I. A.; Neugebauer, J.
2016-06-01
We study the impact of lattice vibrations on magnetic and electronic properties of paramagnetic bcc and fcc iron at finite temperature, employing the disordered local moments molecular dynamics (DLM-MD) method. Vibrations strongly affect the distribution of local magnetic moments at finite temperature, which in turn correlates with the local atomic volumes. Without the explicit consideration of atomic vibrations, the mean local magnetic moment and mean field derived magnetic entropy of paramagnetic bcc Fe are larger compared to paramagnetic fcc Fe, which would indicate that the magnetic contribution stabilizes the bcc phase at high temperatures. In the present study we show that this assumption is not valid when the coupling between vibrations and magnetism is taken into account. At the γ -δ transition temperature (1662 K), the lattice distortions cause very similar magnetic moments of both bcc and fcc structures and hence magnetic entropy contributions. This finding can be traced back to the electronic densities of states, which also become increasingly similar between bcc and fcc Fe with increasing temperature. Given the sensitive interplay of the different physical excitation mechanisms, our results illustrate the need for an explicit consideration of vibrational disorder and its impact on electronic and magnetic properties to understand paramagnetic Fe. Furthermore, they suggest that at the γ -δ transition temperature electronic and magnetic contributions to the Gibbs free energy are extremely similar in bcc and fcc Fe.
Spin flip of neutrinos with magnetic moment in core-collapse supernova
Lychkovskiy, Oleg
2009-01-01
Neutrino with magnetic moment can experience a chirality flip while scattering off charged particles. This effect may lead to important consequences for the dynamics and the neutrino signal of the core-collapse supernova. It is known that if neutrino is a Dirac fermion, then nu_L->nu_R transition induced by the chirality flip leads to the emission of sterile right-handed neutrinos. The typical energies of these neutrinos are rather high, E ~ (100-200)MeV. Neutrino spin precession in the magnetic field either inside the collapsing star or in the interstellar space may lead to the backward transition, nu_R->nu_L. Both possibilities are known to be interesting. In the former case high-energy neutrinos can deliver additional energy to the supernova envelope, which can help the supernova to explode. In the latter case high-energy neutrinos may be detected simultaneously with the "normal" supernova neutrino signal, which would be a smoking gun for the Dirac neutrino magnetic moment. We report the results of the cal...
NMR absolute shielding scale and nuclear magnetic dipole moment of (207)Pb.
Adrjan, Bożena; Makulski, Włodzimierz; Jackowski, Karol; Demissie, Taye B; Ruud, Kenneth; Antušek, Andrej; Jaszuński, Michał
2016-06-28
An absolute shielding scale is proposed for (207)Pb nuclear magnetic resonance (NMR) spectroscopy. It is based on ab initio calculations performed on an isolated tetramethyllead Pb(CH3)4 molecule and the assignment of the experimental resonance frequency from the gas-phase NMR spectra of Pb(CH3)4, extrapolated to zero density of the buffer gas to obtain the result for an isolated molecule. The computed (207)Pb shielding constant is 10 790 ppm for the isolated molecule, leading to a shielding of 10799.7 ppm for liquid Pb(CH3)4 which is the accepted reference standard for (207)Pb NMR spectra. The new experimental and theoretical data are used to determine μ((207)Pb), the nuclear magnetic dipole moment of (207)Pb, by applying the standard relationship between NMR frequencies, shielding constants and nuclear moments of two nuclei in the same external magnetic field. Using the gas-phase (207)Pb and (reference) proton results and the theoretical value of the Pb shielding in Pb(CH3)4, we find μ((207)Pb) = 0.59064 μN. The analysis of new experimental and theoretical data obtained for the Pb(2+) ion in water solutions provides similar values of μ((207)Pb), in the range of 0.59000-0.59131 μN. PMID:27265668
Deák, A.; Simon, E.; Balogh, L.; Szunyogh, L.; dos Santos Dias, M.; Staunton, J. B.
2014-06-01
We develop a self-consistent relativistic disordered local moment (RDLM) scheme aimed at describing finite-temperature magnetism of itinerant metals from first principles. Our implementation in terms of the Korringa-Kohn-Rostoker multiple-scattering theory and the coherent potential approximation allows us to relate the orientational distribution of the spins to the electronic structure, thus a self-consistent treatment of the distribution is possible. We present applications for bulk bcc Fe, L10-FePt, and FeRh ordered in the CsCl structure. The calculations for Fe show significant variation of the local moments with temperature, whereas according to the mean-field treatment of the spin fluctuations the Curie temperature is overestimated. The magnetic anisotropy of FePt alloys is found to depend strongly on intermixing between nominally Fe and Pt layers, and it shows a power-law behavior as a function of magnetization for a broad range of chemical disorder. In the case of FeRh we construct a lattice constant vs temperature phase diagram and determine the phase line of metamagnetic transitions based on self-consistent RDLM free-energy curves.
(83)Kr nuclear magnetic moment in terms of that of (3)He.
Makulski, Włodzimierz
2014-08-01
High resolution NMR spectroscopy was applied to precisely determine the (83)Kr nuclear magnetic dipole moment on the basis of new results available for nuclear magnetic shielding in krypton and helium-3 atoms. Small amounts of (3)He as the solutes and (83)Kr as the buffer gas were observed in (3)He and (83)Kr NMR spectra at the constant external field, B0 = 11.7578 T. In each case, the resonance frequencies (ν(He) and ν(Kr)) were linearly dependent on the density of gaseous solvent. The extrapolation of experimental points to the zero density of gaseous krypton allowed for the evaluation of both resonance frequencies free from intermolecular interactions. By combining these measurements with the recommended (83)Kr chemical shielding value, the nuclear magnetic moment could be determined with much better precision than ever before, μ((83)Kr) = -0.9707297(32)μN, with the improvement due to the greater accuracy of the spectral data.
Tilted-Foil Polarisation and magnetic moments of mirror nuclei at ISOLDE
Bordeanu, C; Thundiyamkulathu baby, L; Lindroos, M
2002-01-01
We report here on the first measurement in an experimental program initiated at the ISOLDE facility at CERN for the measurement of magnetic moments of short-lived radionuclides. The 60~keV ISOLDE beam from the GPS separator is boosted in energy by a 200~kV high-voltage platform, on which the whole experiment is mounted, in order to achieve sufficiently high energy for transmission through the foils of a tilted-foil setup. The 520~keV $^{23}$Mg(2$^+$) nuclei are polarized by the tilted foil technique and the resulting 0$^o$ - 180$^o$ $\\beta$- asymmetry is monitored as a function of the frequency of an rf-applied perturbing magnetic field in an NMR setup.\\\\ In this experiment, earlier asymmetry measurements were confirmed and an NMR resonance was observed, corresponding to a preliminary value of the magnetic moment of 0.533(6) n.m., in agreement with a previous measurement. The measured asymmetry as function of NMR frequency and the fitted resonance curve are presented in the figure. During the e...
Shape and magnetic moment dependence of the dipolar field in Mn12-acetate
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
There is a small fraction of fast-relaxation species in Mn12-acetate, which is utilized to determine the dipolar field of Mn12. Here we report an easier way to precisely obtain the dipolar field by measuring the M-H curves above the blocking temperature of fastrelaxation species. We found that there is a simple linear relationship between the magnetic moment and dipolar field; besides the dipolar field is also dependent on the sample shape, which is consistent with the numerical calculation.
Leading SU(3)-breaking corrections to the baryon magnetic moments in chiral perturbation theory.
Geng, L S; Camalich, J Martin; Alvarez-Ruso, L; Vacas, M J Vicente
2008-11-28
We calculate the baryon magnetic moments using covariant chiral perturbation theory (chiPT) within the extended-on-mass-shell renormalization scheme. By fitting the two available low-energy constants, we improve the Coleman-Glashow description of the data when we include the leading SU(3)-breaking effects coming from the lowest-order loops. This success is in dramatic contrast with previous attempts at the same order using heavy-baryon chiPT and covariant infrared chiPT. We also analyze the source of this improvement with particular attention to the comparison between the covariant results.
SU(3)-breaking corrections to the baryon-octet magnetic moments in chiral perturbation theory
Camalich, J Martin; Geng, L S; Vacas, M J Vicente
2009-01-01
We report a calculation of the baryon magnetic moments using covariant chiral perturbation theory within the extended-on-mass-shell renormalization scheme including intermediate octet and decuplet contributions. By fitting the two available low-energy constants, we improve the Coleman-Glashow description of the data when we include the leading SU(3) breaking effects coming from the lowest-order loops. We compare with previous attempts at the same order using heavy-baryon and covariant infrared chiral perturbation theory, and discuss the source of the differences.
Magnetic moments of lanthanide 3-, 4-nitrobenzoates and 3,4-dinitrobenzoates
International Nuclear Information System (INIS)
The magnetic moments for lanthanide 3-nitro and 4-nitrobenzoates were determined at 298 K and those for 3,4-dinitrobenzoates of rare earth elements over the temperature range 77 - 296 K. The complexes of 3,4-dinitrobenzoates of rare earth were found to obey the Curie-Weiss law. The values of μ calculated for all complexes (except that for europium 3,4-dinitrobenzoates) are close to those obtained for Ln3+ ions by Hund and Van Vleck. The results reveal that irrespective of the kind of ligands (3-nitro, 4-nitro or 3,4-dinitrobenzoates) no influence of their field on lanthanide ions occurs. (author)
Explaining muon magnetic moment and AMS-02 positron excess in a gauged horizontal symmetric model
Tomar, Gaurav
2015-01-01
We extended the standard model with a fourth generation of fermions to explain the discrepancy in the muon magnetic moment and to describe the positron excess observed by AMS-02 experiment. We introduce a gauged $SU(2)_{HV}$ horizontal symmetry between the muon and the 4th generation lepton families and identified the 4th generation right-handed neutrino as the dark matter with mass $\\sim 700$ GeV. The dark matter annihilates through $SU(2)_{HV}$ gauge boson into final states $(\\mu^+ \\mu^-)$ and $(\
Phonon coupling effects in magnetic moments of magic and semi-magic nuclei
Saperstein, E. E.; Achakovskiy, O.; Kamerdzhiev, S.; Krewald, S.; J. Speth; Tolokonnikov, S. V.
2013-01-01
Phonon coupling (PC) corrections to magnetic moments of odd neighbors of magic and semi-magic nuclei are analyzed within the self-consistent Theory of Finite Fermi Systems (TFFS) based on the Energy Density Functional by Fayans et al. The perturbation theory in g_L^2 is used where g_L is the phonon-particle coupling vertex. A model is developed with separating non-regular PC contributions, the rest is supposed to be regular and included into the standard TFFS parameters. An ansatz is proposed...
A 17 keV neutrino and large magnetic moment solution of the solar neutrino puzzle
Akhmedov, E. Kh.; Senjanovic, G.; Tao, Zhijian; Berezhiani, Z. G.
1992-08-01
Zee-type models with Majorons naturally incorporate the 17 keV neutrino but in their minimal version fail to simultaneously solve the solar neutrino puzzle. If there is a sterile neutrino state, a particularly simple solution is found to the solar neutrino problem, which besides nu(sub 17) predicts a light Zeldovich-Konopinski-Mahmoud neutrino nu(sub light) = nu(sub e) + nu(sub mu)(sup c) with a magnetic moment being easily as large as 10(exp -11)(mu)(sub B) through the Barr-Freire-Zee mechanism.
17 keV neutrino and large magnetic moment solution of the solar neutrino puzzle
Akhmedov, Eugeni Kh.; Berezhiani, Zurab G.; Senjanović, Goran; Tao, Zhijian
1993-01-01
Zee-type models with majorons naturally incorporate the 17 keV neutrino but in their minimal version fail to simultaneously solve the solar neutrino puzzle. If there is a sterile neutrino state, we find a particularly simple solution to the solar neutrino problem, which besides ν17 predicts a light Zeldovich-Konopinski-Mahmoud neutrino νlight = νe + νcμ with a magnetic moment being easily as large as 10 -11μB through the Barr-Freire-Zee mechanism.
Srnka, L. J.
1976-01-01
The acquisition of thermoremanent magnetization (TRM) by a cooling spherical shell is studied for internal magnetizing dipole fields, using Runcorn's (1975) theorems on magnetostatics. If the shell cools progressively inward, inner regions acquire TRM in a net field composed of the dipole source term plus a uniform field due to the outer magnetized layers. In this case, the global dipole moment and external remanent field are nonzero when the whole shell has cooled below the Curie point and the source dipole has disappeared. The remanent field outside the shell is found to depend on the thickness, radii, and cooling rate of the shell, as well as the coefficient of TRM and the intensity of the magnetizing field. Some implications for the moon's remanent dipole moment are discussed.
International Nuclear Information System (INIS)
We introduce an extensible multi-fluid moment model in the context of collisionless magnetic reconnection. This model evolves full Maxwell equations and simultaneously moments of the Vlasov-Maxwell equation for each species in the plasma. Effects like electron inertia and pressure gradient are self-consistently embedded in the resulting multi-fluid moment equations, without the need to explicitly solving a generalized Ohm's law. Two limits of the multi-fluid moment model are discussed, namely, the five-moment limit that evolves a scalar pressures for each species and the ten-moment limit that evolves the full anisotropic, non-gyrotropic pressure tensor for each species. We first demonstrate analytically and numerically that the five-moment model reduces to the widely used Hall magnetohydrodynamics (Hall MHD) model under the assumptions of vanishing electron inertia, infinite speed of light, and quasi-neutrality. Then, we compare ten-moment and fully kinetic particle-in-cell (PIC) simulations of a large scale Harris sheet reconnection problem, where the ten-moment equations are closed with a local linear collisionless approximation for the heat flux. The ten-moment simulation gives reasonable agreement with the PIC results regarding the structures and magnitudes of the electron flows, the polarities and magnitudes of elements of the electron pressure tensor, and the decomposition of the generalized Ohm's law. Possible ways to improve the simple local closure towards a nonlocal fully three-dimensional closure are also discussed
Local magnetism in YbCrSb3, an anomalous member of the RECrSb3 series
International Nuclear Information System (INIS)
The intermetallic magnetic compound YbCrSb3, which shows anomalous behavior when compared to other compounds in the RECrSb3 series, is studied near zero magnetic field using μSR. Coherent muon spin precession is observed, unambiguously establishing at the local level that a significant fraction of the sample is in a well-ordered magnetic state below ∼240K. These results confirm, at the local level, that the magnetic transition temperature in YbCrSb3 is higher than those of the other RECrSb3 compounds synthesized to date.
Magnetic moments of 33Mg in the time-odd relativistic mean field approach
Institute of Scientific and Technical Information of China (English)
LI Jian; ZHANG Ying; YAO JiangMing; MENG Jie
2009-01-01
The configuration-fixed deformation constrained relativistic mean field approach with time-odd component has been applied to investigate the ground state properties of 33Mg with effective interaction PK1.The ground state of 33Mg has been found to be prolate deformed,β2=0.23,with the odd neutron in 1/2[330]orbital and the energy-251.85 MeV which is close to the data-252.06 MeV.The magnetic moment-0.9134μN is obtained with the effective electromagnetic current which well reproduces the data -0.7456 μN self-consistently without introducing any parameter.The energy splittings of time reversal conjugate states,the neutron current,the energy contribution from the nuclear magnetic potential,and the effect of core polarization are discussed in detail.
Magnetic moments of 33Mg in the time-odd relativistic mean field approach
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
The configuration-fixed deformation constrained relativistic mean field approach with time-odd component has been applied to investigate the ground state properties of 33Mg with effective interaction PK1.The ground state of 33Mg has been found to be prolate deformed,β2=0.23,with the odd neutron in 1/2[330] orbital and the energy -251.85 MeV which is close to the data -252.06 MeV.The magnetic moment -0.9134 μN is obtained with the effective electromagnetic current which well reproduces the data -0.7456 μN self-consistently without introducing any parameter.The energy splittings of time reversal conjugate states,the neutron current,the energy contribution from the nuclear magnetic potential,and the effect of core polarization are discussed in detail.
Avian magnetic compass can be tuned to anomalously low magnetic intensities.
Winklhofer, Michael; Dylda, Evelyn; Thalau, Peter; Wiltschko, Wolfgang; Wiltschko, Roswitha
2013-07-22
The avian magnetic compass works in a fairly narrow functional window around the intensity of the local geomagnetic field, but adjusts to intensities outside this range when birds experience these new intensities for a certain time. In the past, the geomagnetic field has often been much weaker than at present. To find out whether birds can obtain directional information from a weak magnetic field, we studied spontaneous orientation preferences of migratory robins in a 4 µT field (i.e. a field of less than 10 per cent of the local intensity of 47 µT). Birds can adjust to this low intensity: they turned out to be disoriented under 4 µT after a pre-exposure time of 8 h to 4 µT, but were able to orient in this field after a total exposure time of 17 h. This demonstrates a considerable plasticity of the avian magnetic compass. Orientation in the 4 µT field was not affected by local anaesthesia of the upper beak, but was disrupted by a radiofrequency magnetic field of 1.315 MHz, 480 nT, suggesting that a radical-pair mechanism still provides the directional information in the low magnetic field. This is in agreement with the idea that the avian magnetic compass may have developed already in the Mesozoic in the common ancestor of modern birds.
Magnetic moments of JP = 3/2+ decuplet baryons using statistical model
Kaur, Amanpreet
2015-01-01
A suitable wave function for baryon decuplet is framed with inclusion of sea containing quark- gluon Fock states. Relevant operator formalism is applied to calculate magnetic moments of JP = 3 2 + baryon decuplet. Statistical model assumes decomposition of baryonic state in various quark-gluon Fock states such as jqqqijgi; jqqqijggi; jqqqijgggi with possibility gluon emitting qq pairs condensates due to the subprocesses like g , qq; g , gg and g , qg where qq = uu; dd; ss. Statistical approach and detailed balance principle in combination is used to find the relative probabilities of these Fock states in avor, spin and color space. The total number of partons (sea) in this formalism are restricted to three gluons due to limited free energy of gluon and suppressed number of strange quark-antiquark pairs. The combined approach is used to calculate the magnetic moments, importance of strangeness in the sea (scalar, vector and tensor). Our approach has confirmed the scalar-tensor sea dominancy over vector sea. Va...
Phonon coupling effects in magnetic moments of magic and semi-magic nuclei
Saperstein, E E; Kamerdzhiev, S; Krewald, S; Speth, J; Tolokonnikov, S V
2013-01-01
Phonon coupling (PC) corrections to magnetic moments of odd neighbors of magic and semi-magic nuclei are analyzed within the self-consistent Theory of Finite Fermi Systems (TFFS) based on the Energy Density Functional by Fayans et al. The perturbation theory in g_L^2 is used where g_L is the phonon-particle coupling vertex. A model is developed with separating non-regular PC contributions, the rest is supposed to be regular and included into the standard TFFS parameters. An ansatz is proposed to take into account the so-called tadpole term which ensures the total angular momentum conservation with g_L^2 accuracy. An approximate method is suggested to take into account higher order terms in g_L^2. Calculations are carried out for four odd-proton chains, the odd Tl, Bi, In and Sb ones. Different PC corrections strongly cancel each other. In the result, the total PC correction to the magnetic moment in magic nuclei is, as a rule, negligible. In non-magic nuclei considered it is noticeable and, with only one exce...
Magnetic moments of nuclei near Z=40, 50 and 82 measured by nuclear orientation
International Nuclear Information System (INIS)
Magnetic moments of ground and isomeric states by static nuclear orientation at low temperature are measured. The following nuclei, standing near Z=40, 50 and 82, 87Y, 93 Mosup(m), 93-94Tc, 110Insup(m) 106Agsup(m), 189-191Pt have been studied. Results are compared with single particle predictions for (1g9/2) and (3p3/2) orbitals of the shell model, corrected for mesonic and core-polarization effects. A number of multipole mixing ratios of transitions in the daughter nuclei have been determined. Experiments have been done with the first top loading, rapid access 3He-4He dilution refrigator. This feature enlarges the field of the method to shorter lifetimes nuclei. Formal development of nuclear orientation coefficients are also presented with both, a randomly oriented electric quadrupole interaction and a polarized magnetic dipole interaction, acting in the oriented state. The numerical results are put in a table for all spins from I=1 to 8, a wide range of temperature and ratio of quadrupole to dipole interactions strenghts values. These calculations enable to get electric quadrupole moments of long lived nuclei from low temperature nuclear orientation in non-cubic polycristalline samples
First-Principles Study of the Local Magnetic Moment on a N-Doped Cu2O(111)Surface
Institute of Scientific and Technical Information of China (English)
王治
2011-01-01
First-principles calculations based on density functional theory within the generalized gradient approximation are used to study on magnetism in N-doped Cu2O.It is interesting that nitrogen does not induce magnetism in bulk Cu2O,while shows a total magnetism moment of 1.0μB at the Cu2O(111)surface,which is mainly localized on the doped N atoms.The local magnetic moment at the N-doped Cu2O(111)surface can be explained in terms of the surface state.%First-principles calculations based on density functional theory within the generalized gradient approximation are used to study on magnetism in N-doped C112O. It is interesting that nitrogen does not induce magnetism in bulk Cu2O, while shows a total magnetism moment of 1.0μB at the C112O (111) surface, which is mainly localized on the doped JV atoms. The local magnetic moment at the N-doped Cu2O (111) surface can be explained in terms of the surface state.
Okabayashi, Jun; Sukegawa, Hiroaki; Wen, Zhenchao; Inomata, Koichiro; Mitani, Seiji
2013-09-01
Perpendicular magnetic anisotropy (PMA) in Heusler alloy Co2FeAl thin films sharing an interface with a MgO layer is investigated by angular-dependent x-ray magnetic circular dichroism. Orbital and spin magnetic moments are deduced separately for Fe and Co 3d electrons. In addition, the PMA energies are estimated using the orbital magnetic moments parallel and perpendicular to the film surfaces. We found that PMA in Co2FeAl is determined mainly by the contribution of Fe atoms with large orbital magnetic moments, which are enhanced at the interface between Co2FeAl and MgO. Furthermore, element specific magnetization curves of Fe and Co are found to be similar, suggesting the existence of ferromagnetic coupling between Fe and Co PMA directions.
Directed magnetic field induced assembly of high magnetic moment cobalt nanowires
DEFF Research Database (Denmark)
Srivastava, Akhilesh Kumar; Madhavi, S.; Ramanujan, R.V.
2010-01-01
A directed magnetic field induced assembly technique was employed to align two phase (h.c.p. + f.c.c.) cobalt nanoparticles in a mechanically robust long wire morphology. Co nanoparticles with an average size of 4.3 nm and saturation magnetization comparable to bulk cobalt were synthesized...... by borohydride reduction followed by size selection and magnetic field induced assembly. The coercivity of these nanowires was higher than their nanoparticle counterpart due to shape anisotropy. The experimental coercivity values of the nanowires were lower than the predictions of the coherent rotation, fanning...
Anomalous magnetoresistance in NiMnGa thin films
Golub, Vladimir O.; Vovk, Andriy Ya.; Malkinski, Leszek; O'Connor, Charles J.; Wang, Zhenjun; Tang, Jinke
2004-10-01
The origin of anomalous negative magnetoresistance and its temperature dependence in polycrystalline Ni -Mn-Ga films prepared by pulse laser deposition was studied. The investigation of structural, transports, magnetic, and ferromagnetic resonance properties of the films suggests contributions of different mechanisms in magnetotransport. At low magnetic fields the main contribution to magnetoresistance is due to the transport between the areas with different orientation of magnetic moments, while at high fields it is an electron scattering of in spin-disordered areas.
Institute of Scientific and Technical Information of China (English)
HE Jun; DONG Yu-Bing
2005-01-01
We derive the exchange currents of pseudoscalar, vector, and scalar mesons from Feynman diagrams, and use them to calculate the magnetic form factors of nucleon and △(1232). The magnetic moments and electromagnetic radii are obtained by using those form factors and the parameters determined from the masses of nucleon and △(1232).We find the magnetic moments and electromagnetic radii of nucleon and △(1232) can be produced very well in the extended Goldstone-Boson-exchange model in which all of pseudoscalar, vector, and scalar meson nonet are included.The magnetic moments of △(1232) are closer to experiment values and results from lattice calculation than the results obtained by the model without other mesons except for pion and sigma.
Measurement of Magnetic Moment at the Atomic Scale in a High TC Molecular Based Magnet
Arrio, M.-A.; Sainctavit, Ph.; Cartier dit Moulin, Ch.; Brouder, Ch.; Groot, F.M.F. de; Mallah, T.; Verdaguer, M.
2001-01-01
The molecular-based magnet Cs^(I) [Ni^(II) Cr^(III) (CN)6]-2H2O is a ferromagnetic with a Curie temperature TC ) 90 K. Its structure consists of face-centered cubic lattice of Ni^(II) ions connected by Cr(CN)6 entities. We have recorded X-ray magnetic circular dichroism (XMCD) at nickel L2,3 edges.
Zhou, Y.; Yu, T.; Wu, M. W.
2013-06-01
We report an anomalous scaling of the D’yakonov-Perel’ spin relaxation with the momentum relaxation in semiconductor quantum wells under a strong magnetic field in the Voigt configuration. We focus on the case in which the external magnetic field is perpendicular to the spin-orbit-coupling-induced effective magnetic field and its magnitude is much larger than the latter one. It is found that the longitudinal spin relaxation time is proportional to the momentum relaxation time even in the strong-scattering limit, indicating that the D’yakonov-Perel’ spin relaxation demonstrates Elliott-Yafet-like behavior. Moreover, the transverse spin relaxation time is proportional (inversely proportional) to the momentum relaxation time in the strong- (weak-) scattering limit, both in the opposite trends against the well-established conventional D’yakonov-Perel’ spin relaxation behaviors. We further demonstrate that all the above anomalous scaling relations come from the unique form of the effective inhomogeneous broadening.
Sun, Jingbo; Liu, Xiaoming; Zhou, Ji; Kudyshev, Zhaxylyk; Litchinitser, Natalia M
2015-11-04
Anomalous field enhancement accompanied by resonant absorption phenomenon was originally discussed in the context of plasma physics and in applications related to radio-communications between the ground and spacecraft returning to Earth. Indeed, there is a critical period of time when all communications are lost due to the reflection/absorption of electromagnetic waves by the sheath of plasma created by a high speed vehicle re-entering the atmosphere. While detailed experimental studies of these phenomena in space are challenging, the emergence of electromagnetic metamaterials enables researchers exceptional flexibility to study them in the laboratory environment. Here, we experimentally demonstrated the strong localized field enhancement of magnetic field for an electromagnetic wave propagating in Mie-resonance-based inhomogeneous metamaterials with magnetic permeability gradually changing from positive to negative values. Although these experiments were performed in the microwave frequency range, the proposed all-dielectric approach to transition metamaterials can be extended to terahertz, infrared, and visible frequencies. We anticipate that these results, besides most basic science aspects, hold the potential for numerous applications, including low-intensity nonlinear transformation optics, topological photonics, and the broader area of surface and interface science.
Anomalous Hall effect sensors based on magnetic element doped topological insulator thin films
Ni, Yan; Zhang, Zhen; Nlebedim, Ikenna; Jiles, David
Anomalous Hall effect (AHE) is recently discovered in magnetic element doped topological insulators (TIs), which promises low power consumption highly efficient spintronics and electronics. This discovery broaden the family of Hall effect (HE) sensors. In this work, both HE and AHE sensor based on Mn and Cr doped Bi2Te3 TI thin films will be systematically studied. The influence of Mn concentration on sensitivity of MnxBi2-xTe3 HE sensors will be discussed. The Hall sensitivity increase 8 times caused by quantum AHE will be reported. AHE senor based on Cr-doped Bi2Te3 TI thin films will also be studied and compared with Mn doped Bi2Te3 AHE sensor. The influence of thickness on sensitivity of CrxBi2-xTe3 AHE sensors will be discussed. Ultrahigh Hall sensitivity is obtained in Cr doped Bi2Te3. The largest Hall sensitivity can reach 2620 Ω/T in sensor which is almost twice higher than that of the normal semiconductor HE sensor. Our work indicates that magnetic element doped topological insulator with AHE are good candidates for ultra-sensitive Hall effect sensors.
Liang, Yingjie; Ye, Allen Q.; Chen, Wen; Gatto, Rodolfo G.; Colon-Perez, Luis; Mareci, Thomas H.; Magin, Richard L.
2016-10-01
Non-Gaussian (anomalous) diffusion is wide spread in biological tissues where its effects modulate chemical reactions and membrane transport. When viewed using magnetic resonance imaging (MRI), anomalous diffusion is characterized by a persistent or 'long tail' behavior in the decay of the diffusion signal. Recent MRI studies have used the fractional derivative to describe diffusion dynamics in normal and post-mortem tissue by connecting the order of the derivative with changes in tissue composition, structure and complexity. In this study we consider an alternative approach by introducing fractal time and space derivatives into Fick's second law of diffusion. This provides a more natural way to link sub-voxel tissue composition with the observed MRI diffusion signal decay following the application of a diffusion-sensitive pulse sequence. Unlike previous studies using fractional order derivatives, here the fractal derivative order is directly connected to the Hausdorff fractal dimension of the diffusion trajectory. The result is a simpler, computationally faster, and more direct way to incorporate tissue complexity and microstructure into the diffusional dynamics. Furthermore, the results are readily expressed in terms of spectral entropy, which provides a quantitative measure of the overall complexity of the heterogeneous and multi-scale structure of biological tissues. As an example, we apply this new model for the characterization of diffusion in fixed samples of the mouse brain. These results are compared with those obtained using the mono-exponential, the stretched exponential, the fractional derivative, and the diffusion kurtosis models. Overall, we find that the order of the fractal time derivative, the diffusion coefficient, and the spectral entropy are potential biomarkers to differentiate between the microstructure of white and gray matter. In addition, we note that the fractal derivative model has practical advantages over the existing models from the
Haldar, Soumyajyoti
2014-05-09
In this work, we have studied the chemical and magnetic interactions of Fen (n=1–6) clusters with vacancy defects (monovacancy to correlated vacancies with six missing C atoms) in a graphene sheet by ab initio density functional calculations combined with Hubbard U corrections for correlated Fe-d electrons. It is found that the vacancy formation energies are lowered in the presence of Fe, indicating an easier destruction of the graphene sheet. Due to strong chemical interactions between Fe clusters and vacancies, a complex distribution of magnetic moments appear on the distorted Fe clusters which results in reduced averaged magnetic moments compared to the free clusters. In addition to that, we have calculated spin-dipole moments and magnetic anisotropy energies. The calculated spin-dipole moments arising from anisotropic spin density distributions vary between positive and negative values, yielding increased or decreased effective moments. Depending on the cluster geometry, the easy axis of magnetization of the Fe clusters shows in-plane or out-of-plane behavior.
Bialynicki-Birula, Iwo; Radożycki, Tomasz
2016-01-01
The motion of a neutral atom endowed with a magnetic moment interacting with the magnetic field is determined from the Ehrenfest-like equations of motion. These equations for the average values of the translational and spin degrees of freedom are derived from the Schr\\"odinger-Pauli wave equation and they form a set of nine coupled nonlinear evolution equations. The numerical and analytic solutions of these equations are obtained for the combination of the rotating magnetic field of a wave ca...
Afach, S.; Baker, C.A.; Ban, G.; Bison, G.; K. Bodek; Chowdhuri, Z.; Daum, M.; Fertl, M.; Franke, B.; Geltenbort, P.(Institut Laue-Langevin, Grenoble Cedex 9, 38042, France); Green, K.; van der Grinten, M. G. D.; Grujic, Z.; Harris, P.G.; Heil, W.
2015-01-01
We report on the measurement of a Larmor frequency shift proportional to the electric-field strength for $^{199}{\\rm Hg}$ atoms contained in a volume permeated with aligned magnetic and electric fields. This shift arises from the interplay between the inevitable magnetic field gradients and the motional magnetic field. The proportionality to electric-field strength makes it apparently similar to an electric dipole moment (EDM) signal, although unlike an EDM this effect is P- and T-conserving....
Quantum anomalous Hall effect with higher plateaus.
Wang, Jing; Lian, Biao; Zhang, Haijun; Xu, Yong; Zhang, Shou-Cheng
2013-09-27
The quantum anomalous Hall (QAH) effect in magnetic topological insulators is driven by the combination of spontaneous magnetic moments and spin-orbit coupling. Its recent experimental discovery raises the question if higher plateaus can also be realized. Here, we present a general theory for a QAH effect with higher Chern numbers and show by first-principles calculations that a thin film magnetic topological insulator of Cr-doped Bi2(Se,Te)3 is a candidate for the C=2 QAH insulator. Remarkably, whereas a higher magnetic field leads to lower Hall conductance plateaus in the integer quantum Hall effect, a higher magnetic moment leads to higher Hall conductance plateaus in the QAH effect.
Institute of Scientific and Technical Information of China (English)
胡社军; 刘正义; 等
2002-01-01
The structure and magnetic properties of Ce2Co17-xMx(M=Ga,Al and Si)compounds for Mcomcentrations up to x=5 were studied by means of X-ray diffraction and magnetic measurements,The experimental results show that the Curie temperatures and Co spontaneous magnetization decrease significantly with increasing the addition of non-magnetic substitutional atoms,and that Si which has a minimum solid solubility ic Ce2Co17causes a largest reduction of Curie temperature,spontaneous magnetization and moment perCo atom compared with Ga and Al.
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
The structure and magnetic properties of Ce2Co17-xMx(M=Ga,Al and Si) compounds for M concentrations up to x=5 were studied by means of X-ray diffraction and magnetic measurements. The experimental results show that the Curie temperatures and Co spontaneous magnetization decrease significantly with increasing the addition of non-magnetic substitutional atoms, and that Si which has a minimum solid solubility in Ce2Co17 causes a largest reduction of Curie temperature, spontaneous magnetization and moment per Co atom compared with Ga and Al.
Covariant Spectator Theory of np scattering: Deuteron magnetic moment and form factors
Energy Technology Data Exchange (ETDEWEB)
Gross, Franz L. [JLAB
2014-06-01
The deuteron magnetic moment is calculated using two model wave functions obtained from 2007 high precision fits to $np$ scattering data. Included in the calculation are a new class of isoscalar $np$ interaction currents which are automatically generated by the nuclear force model used in these fits. After normalizing the wave functions, nearly identical predictions are obtained: model WJC-1, with larger relativistic P-state components, gives 0.863(2), while model WJC-2 with very small $P$-state components gives 0.864(2) These are about 1\\% larger than the measured value of the moment, 0.857 n.m., giving a new prediction for the size of the $\\rho\\pi\\gamma$ exchange, and other purely transverse interaction currents that are largely unconstrained by the nuclear dynamics. The physical significance of these results is discussed, and general formulae for the deuteron form factors, expressed in terms of deuteron wave functions and a new class of interaction current wave functions, are given.
The spin and orbital contributions to the total magnetic moments of free Fe, Co, and Ni clusters
Energy Technology Data Exchange (ETDEWEB)
Meyer, Jennifer; Tombers, Matthias; Wüllen, Christoph van; Niedner-Schatteburg, Gereon, E-mail: gns@chemie.uni-kl.de [Fachbereich Chemie and Forschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern (Germany); Peredkov, Sergey; Eberhardt, Wolfgang [Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany and DESY-CFEL, Notkestr. 85, 22607 Hamburg (Germany); Neeb, Matthias [Helmholtz-Zentrum für Materialien und Energie, BESSY II, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Palutke, Steffen; Martins, Michael; Wurth, Wilfried [Institut für Experimentalphysik, Universität Hamburg, Luruper Chausee 149, 22761 Hamburg (Germany)
2015-09-14
We present size dependent spin and orbital magnetic moments of cobalt (Co{sub n}{sup +}, 8 ≤ n ≤ 22), iron (Fe{sub n}{sup +}, 7 ≤ n ≤ 17), and nickel cluster (Ni{sub n}{sup +}, 7 ≤ n ≤ 17) cations as obtained by X-ray magnetic circular dichroism (XMCD) spectroscopy of isolated clusters in the gas phase. The spin and orbital magnetic moments range between the corresponding atomic and bulk values in all three cases. We compare our findings to previous XMCD data, Stern-Gerlach data, and computational results. We discuss the application of scaling laws to the size dependent evolution of the spin and orbital magnetic moments per atom in the clusters. We find a spin scaling law “per cluster diameter,” ∼n{sup −1/3}, that interpolates between known atomic and bulk values. In remarkable contrast, the orbital moments do likewise only if the atomic asymptote is exempt. A concept of “primary” and “secondary” (induced) orbital moments is invoked for interpretation.
Leading SU(3)-breaking corrections to the baryon magnetic moments in Chiral Perturbation Theory
Geng, L S; Alvarez-Ruso, L; Vacas, M J Vicente
2008-01-01
We calculate the baryon magnetic moments using covariant Chiral Perturbation Theory ($\\chi$PT) within the Extended-on-mass-shell (EOMS) renormalization scheme. By fitting the two available low-energy constants, we improve the Coleman-Glashow description of the data when we include the leading SU(3) breaking effects coming from the lowest-order loops. This success is in dramatic contrast with previous attempts at the same order using Heavy Baryon (HB) $\\chi$PT and covariant Infrared (IR) $\\chi$PT. We also analyze the source of this improvement with particular attention on the comparison between the covariant results, and conclude that SU(3) baryon $\\chi$PT coverges better within the EOMS renormalization scheme.
Magnetic moment and plasma environment of HD 209458b as determined from Ly$\\alpha$ observations
Kislyakova, K G; Lammer, H; Odert, P; Khodachenko, M L
2014-01-01
Transit observations of HD 209458b in the stellar Lyman-$\\alpha$ (Ly$\\alpha$) line revealed strong absorption in both blue and red wings of the line interpreted as hydrogen atoms escaping from the planet's exosphere at high velocities. The following sources for the absorption were suggested: acceleration by the stellar radiation pressure, natural spectral line broadening, charge exchange with stellar wind. We reproduce the observation by means of modelling that includes all aforementioned processes. Our results support a stellar wind with a velocity of $\\approx400$ km$\\times$s$^{-1}$ at the time of the observation and a planetary magnetic moment of $\\approx 1.6 \\times 10^{26}$ A$\\times$m$^2$.
Mass and magnetic dipole moment of negative parity heavy baryons with spin--3/2
Azizi, K
2015-01-01
We calculate the mass and residue of the heavy spin--3/2 negative parity baryons with single heavy bottom or charm quark by the help of a two-point correlation function. We use the obtained results to investigate the diagonal radiative transitions among the baryons under consideration. In particular, we compute corresponding transition form factors via light cone QCD sum rules which are then used to obtain the magnetic dipole moments of the heavy spin--3/2 negative parity baryons. We remove the pollutions coming from the positive parity spin--3/2 and positive/negative parity spin--1/2 baryons by constructing sum rules for different Lorentz structures. We compare the results obtained with the existing theoretical predictions.
Masses and magnetic moments of triple heavy flavour baryons in hypercentral model
Indian Academy of Sciences (India)
Bhavin Patel; Ajay Majethiya; P C Vinodkumar
2009-04-01
Triple heavy flavour baryons are studied using the hypercentral description of the three-body system. The confinement potential is assumed as hypercentral Coulomb plus power potential with power index . The ground state ($J^{P} = \\dfrac{1}{2}^{+}$ and $\\dfrac{3}{2}^{+}$) masses of heavy flavour baryons are computed for different power index, starting from 0.5 to 2.0. The predicted masses are found to attain a saturated value with respect to variation in p beyond the power index > 1.0. Using the spin-flavour structure of the constituting quarks and by defining effective mass of the confined quarks within the baryons, the magnetic moments are computed with no additional free parameters.
Magnetic moment of $^{17}$Ne using beta -NMR and tilted foil polarization
Baby, L T; Hass, M; Haas, H; Weissman, L; Brown, B A
2004-01-01
We report on the measurement of the magnetic moment of the ground state of /sup 17/Ne. Radioactive /sup 17/Ne nuclei were delivered from the high resolution mass separator at ISOLDE onto a high voltage platform at -200 kV and were polarized using the tilted foil polarization method. The polarized nuclei were implanted into a Pt stopper situated in a liquid-helium cooled beta -NMR apparatus and the asymmetry destruction of the ensuing beta rays was monitored as a function of the rf frequency applied to the polarized nuclei. The measured value of mu = 0.74 +or- 0.03 affirms the nu p/sub 1/2//sup - / nature of the ground state of /sup 17/Ne and is compared to shell model calculations. (10 refs).
Radiative corrections to the magnetic moments of the proton and the neutron
Kaiser, N
2016-01-01
We estimate the radiative corrections of order $\\alpha/\\pi$ to the magnetic moments of the proton and the neutron. The photon-loop diagram of the vertex-correction type is evaluated with phenomenological nucleon vector form factors. Infrared-finiteness and gauge-invariance require the inclusion of the wave-function renormalization factor from the self-energy diagram. Using recent empirical form factor parametrizations the corrections amount to $\\delta\\kappa_p= -3.42 \\cdot 10^{-3}$ and $\\delta\\kappa_n= 1.34 \\cdot 10^{-3}$. We study also the effects from photon-loops with internal $\\Delta(1232)$-isobars. For two customary versions of the $\\Delta N\\gamma $-vertex and spin-3/2 propagator, these radiative corrections have values of $\\delta\\kappa_p^{(\\Delta)}= (-0.9,\\, 0.0)\\!\\cdot\\! 10^{-3}$ and $\\delta\\kappa_n^{(\\Delta)} = (1.2,\\,-0.8)\\!\\cdot\\! 10^{-3}$, respectively.
Final results on the neutrino magnetic moment from the MUNU experiment
Daraktchieva, Z; Avenier, M; Broggini, C; Busto, J; Cerna, C; Juget, F R; Koang, D H; Lamblin, J; Lebrun, D; Link, O; Puglierin, G; Stutz, A; Tadsen, A; Vuilleumier, J L; Zacek, V
2005-01-01
The MUNU detector was designed to study neutrino-electron elastic scattering at low energy. The central component is a Time Projection Chamber filled with CF4 gas, surrounded by an anti-Compton detector. The experiment was carried out at the Bugey (France) nuclear reactor. In this paper we present the final analysis of the data recorded at 3 bar and 1 bar pressure. Both the energy and the scattering angle of the recoil electron are measured. From the 3 bar data a new upper limit on the neutrino magnetic moment was derived. At 1 bar electron tracks down to 150 keV were reconstructed, demonstrating the potentiality of the experimental technique for future applications in low energy neutrino physics.
Phonon coupling effects in magnetic moments of magic and semimagic nuclei
Saperstein, E. E.; Achakovskiy, O. I.; Kamerdzhiev, S. P.; Krewald, S.; Speth, J.; Tolokonnikov, S. V.
2014-08-01
Phonon coupling (PC) corrections to magnetic moments of odd neighbors of magic and semimagic nuclei are analyzed within the self-consistent Theory of Finite Fermi Systems (TFFS) based on the Energy Density Functional by S. A. Fayans et al. The perturbation theory in g {/L 2} is used where g L is the phonon-particle coupling vertex. A model is developed with separating non-regular PC contributions, the rest is supposed to be regular and included into the standard TFFS parameters. An ansatz is proposed to take into account the so-called tadpole term which ensures the total angular momentum conservation with g {/L 2} accuracy. An approximate method is suggested to take into account higher-order terms in g {/L 2}. Calculations are carried out for four odd-proton chains, the odd Tl, Bi, In, and Sb ones. Different PC corrections strongly cancel each other. In the result, the total PC correction to the magnetic moment in magic nuclei is, as a rule, negligible. In non-magic nuclei considered it is noticeable and, with only one exception, negative. On average it is of the order of -(0.1-0.5) µ N and improves the agreement of the theory with the data. Simultaneously we calculated the gyromagnetic ratios g {/L ph} of all low-lying phonons in 208Pb. For the 3{1/-} state it is rather close to the Bohr-Mottelson model prediction whereas for other L phonons, two 5- and six positive parity states, the difference from the Bohr-Mottelson values is significant.
Torres, D A
2016-01-01
The experimental study of magnetic moments for nuclear states near the ground state, $I \\ge 2$, provides a powerful tool to test nuclear structure models. The study of magnetic moments in nuclei far away from the stability line is the next frontier in such studies. Two techniques have been utilized to populated low-spin states in radioactive nuclei: coulomb excitation reactions using radioactive nuclei, and the transfer of $\\alpha$ particles to stable beams to populate low spin states in radioactive nuclei. A presentations of these two techniques, along with the experimental challenges presented for future uses with nuclei far away from the stability line, will be presented.
Weinstein, Roy; Parks, Drew; Sawh, Ravi-Persad; Carpenter, Keith; Davey, Kent
2016-04-01
Recent experiments on pulsed-zero field cool magnetization of bulk high Jc YBCO (YBa2Cu3O7-δ) have shown unexpected results. For example, reproducible, non-destructive, rapid, giant field leaps (GFLs) to higher penetrated field are observed. The observations are inconsistent with the critical state model (CSM), in several aspects. Additional experiments have been pursued in an attempt to clarify the physics involved in the observed anomalies. Here, we present experimental results for the Jc dependence of the anomalous features. It is found that the sudden field increase in the GFL is a monotonically increasing function of Jc. The ratio of required pulsed field amplitude, BA,max, to obtain maximum trappable field, BT,max, which CSM predicts to be ≥2.0, gradually approaches 1.0 at high Jc. Tests using values of pulsed, applied field BA,max just below the GFL exhibit two additional anomalies: (i) At high Jc, the highest trapped field is up to ˜6 times lower than predicted by CSM, and (ii) the measured Lorentz force as a function of Jc deviates sharply from CSM predictions. The data rule out heating effects and pinning center geometry as possible physical causes of these anomalies. A speculative cause is considered.
Dipole moments of the τ-neutrino
International Nuclear Information System (INIS)
Bounds on the anomalous magnetic moment and the electric dipole moment of the τ -neutrino are calculated through the reaction e+e- → ν ν-bar γ at the Z1-pole, and in the framework of a left-right symmetric model. The results are based on the recent data reported by the L3 Collaboration at CERN LEP. We find that the bounds are almost independent of the mixing angle φ of the model in the allowed experimental range for this parameter
Sun, X.; Wang, B.; Pratt, A.; Yamauchi, Y.
2014-07-01
The geometric, electronic, and magnetic structures of a manganese phthalocyanine (MnPc) molecule on an antiferromagnetic IrMn(100) surface are studied by density functional theory calculations. Two kinds of orientation of the adsorbed MnPc molecule are predicted to coexist due to molecular self-assembly on the surface—a top-site geometry with the Mn-N bonds aligned along the ⟨100⟩ direction, and a hollow-site orientation in which the Mn-N bonds are parallel to the ⟨110⟩ direction. The MnPc molecule is antiferromagnetically coupled to the substrate at the top site with a slight reduction in the magnetic moment of the Mn atom of the MnPc molecule (Mnmol). In contrast, the magnetic moment of the Mnmol is enhanced to 4.28 μB at the hollow site, a value larger than that in the free MnPc molecule (3.51 μB). Molecular distortion induced by adsorption is revealed to be responsible for the enhancement of the magnetic moment. Furthermore, the spin polarization of the Mnmol atom at around the Fermi level is found to change from negative to positive through an elongation of the Mn-N bonds of the MnPc. We propose that a reversible switch of the low/high magnetic moment and negative/positive spin polarization might be realized through some mechanical engineering methods.
International Nuclear Information System (INIS)
The geometric, electronic, and magnetic structures of a manganese phthalocyanine (MnPc) molecule on an antiferromagnetic IrMn(100) surface are studied by density functional theory calculations. Two kinds of orientation of the adsorbed MnPc molecule are predicted to coexist due to molecular self-assembly on the surface—a top-site geometry with the Mn–N bonds aligned along the 〈100〉 direction, and a hollow-site orientation in which the Mn–N bonds are parallel to the 〈110〉 direction. The MnPc molecule is antiferromagnetically coupled to the substrate at the top site with a slight reduction in the magnetic moment of the Mn atom of the MnPc molecule (Mnmol). In contrast, the magnetic moment of the Mnmol is enhanced to 4.28 μB at the hollow site, a value larger than that in the free MnPc molecule (3.51 μB). Molecular distortion induced by adsorption is revealed to be responsible for the enhancement of the magnetic moment. Furthermore, the spin polarization of the Mnmol atom at around the Fermi level is found to change from negative to positive through an elongation of the Mn–N bonds of the MnPc. We propose that a reversible switch of the low/high magnetic moment and negative/positive spin polarization might be realized through some mechanical engineering methods
Drake, J F; Swisdak, M; Chamoun, J N
2009-01-01
The recent observations of the anomalous cosmic ray (ACR) energy spectrum as Voyagers 1 and 2 crossed the heliospheric termination shock have called into question the conventional shock source of these energetic particles. We suggest that the sectored heliospheric magnetic field, which results from the flapping of the heliospheric current sheet, piles up as it approaches the heliopause, narrowing the current sheets that separate the sectors and triggering the onset of collisionless magnetic reconnection. Particle-in-cell simulations reveal that most of the magnetic energy is released and most of this energy goes into energetic ions with significant but smaller amounts of energy going into electrons. The energy gain of the most energetic ions results from their reflection from the ends of contracting magnetic islands, a first order Fermi process. The energy gain of the ions in contracting islands increases their parallel (to the magnetic field ${\\bf B}$) pressure $p_\\parallel$ until the marginal firehose condi...
Synthesis of high magnetic moment soft magnetic nanocomposite powders for RF filters and antennas
Chinnasamy, Chins; Malallah, Yaaqoub; Jasinski, Melania M.; Daryoush, Afshin S.
2015-04-01
Fe60Co40 alloy nanoparticles with an average particle size of 30 nm were successfully synthesized in gram scale batches using the modified polyol process. The X-ray diffraction and microstructure studies clearly show the formation of the alloy nanoparticles. The saturation magnetization for the gram scale synthesized Fe60Co40 alloy nanoparticles is in the range of 190-205 emu/g at room temperature. The as-synthesized nanoparticles were used to fabricate transmission lines on FR4 substrate to perform radio frequency (RF) characterization of the nanoparticles at ISM RF bands of interest (all in GHz range). The complex permeability extraction of composite Fe60Co40 nanoparticles were performed using perturbation technique applied to microstrip transmission lines by relative measurement of full two port scattering parameter with respect to a baseline FR4 substrate. The extracted results show attractive characteristics for small size antennas and filters.
Boda, Aalu; Kumar, D. Sanjeev; Sankar, I. V.; Chatterjee, Ashok
2016-11-01
The problem of a parabolically confined two-dimensional semiconductor GaAs quantum dot with two interacting electrons in the presence of an external magnetic field and the spin-Zeeman interaction is studied using a method of numerical diagonalization. The energy spectrum is calculated as a function of the magnetic field. The magnetic moment (M) and the magnetic susceptibility (χ) show zero temperature diamagnetic peaks due to the exchange induced singlet-triplet transitions. The position and the number of these peaks depend both on the confinement strength of the quantum dot and the strength of the electron-electron interaction (β) .
Directory of Open Access Journals (Sweden)
Tsutomu Ando, Noriyuki Hirota and Hitoshi Wada
2009-01-01
Full Text Available In this paper, the motion of a chainlike cluster of feeble magnetic particles induced by high magnetic field is discussed on the basis of the results of numerical simulations. The simulations were performed on glass particles with a diameter of 0.8 mm; and the viscosity, applied magnetic field and magnetic properties of the surrounding medium were changed. In addition to the magnetic field and the difference in magnetic susceptibility between the particles and the surrounding medium, the obtained results indicate that the viscosity is an essential factor for the formation of the chainlike alignment of feeble magnetic particles. We also carried out simulations using glass particles with a smaller diameter of 0.1 mm. Chainlike clusters were produced similar to those of ferromagnetic particles formed in a ferromagnetic fluid.
Correlation of magnetic moments and angular momenta for stars and planets
Dolginov, A
2016-01-01
The observed correlation of the angular momenta $L^{ik}$ and magnetic moments $\\mu_{lm}$ of celestial bodies (the Sun, planets and stars) was discussed by many authors but without any explanation. In this paper a possible explanation of this phenomenon is suggested. It is shown that the function $\\Phi_{lm} =(\\eta/r_g)L^{ik}R_{iklm}$ satisfy Maxwell equations and can be considered as a function which determine the electro-magnetic properties of rotating heavy bodies. The $R_{iklm}$ is the Riemann tensor, which determines the gravitational field of the body, $r_g$ is the gravitational radius of the body, and $\\eta$ is the constant which has to be determined by observations. The field $\\Phi_{lm}$ describe the observed $\\mu \\leftrightarrow L$ correlation. In particular the function $\\Phi_{l0}$ describe the electric field created by rotating heavy bodies. It is possible that the observed electric field of the Earth is created by the Earth rotation
KamLAND Bounds on Solar Antineutrinos and neutrino transition magnetic moments
Torrente-Lujan, E
2003-01-01
We investigate the possibility of detecting solar antineutrinos with the KamLAND experiment. These antineutrinos are predicted by spin-flavor oscillations at a significant rate even if this mechanism is not the leading solution to the SNP. The recent evidence from SNO shows that the solar flux could contain a residual component including sterile neutrinos and/or the antineutrinos of the active flavors. KamLAND is sensitive to antineutrinos originated from solar ${}^8$B neutrinos. From KamLAND negative results after 145 days of data taking, we obtain model independent limits on the total flux of solar antineutrinos $\\Phi({}^8 B)< 1.1-3.5\\times 10^4 cm^{-2} s^{-1}$, more than one order of magnitude smaller than existing limits,and on their appearance probability $P<0.15%$ (95% CL). Assuming a concrete model for antineutrino production by spin-flavor precession, this upper bound implies an upper limit on the product of the intrinsic neutrino magnetic moment and the value of the solar magnetic field $\\mu B&...
Bounds on the magnetic moment of the τ-neutrino via the process e+e-→v(v)γ
Institute of Scientific and Technical Information of China (English)
C.Aydin; M.Bayar; N.Kilic
2008-01-01
Using Breit-Wigner resonance relation,bounds on the magnetic moment of the tau-neutrino are calculated through the reaction e+e-→v(v)γ at the neutral boson pole in the framework of a superstringinspired E6 model which has one extra low-energy neutral gauge boson and a LRSM.
O'Brien, T. P.
2015-01-01
in the magnetospheric magnetic field produce drift shell splitting, which causes the radial (drift shell) invariant to sometimes depend on pitch angle. Where drift shell splitting is significant, pitch angle scattering leads to diffusion in all three invariants of the particle's motion, including cross diffusion. We examine the magnitude of drift shell splitting-related anomalous diffusion for outer zone electrons compared to conventional diffusion in the absence of drift shell splitting. We assume that the primary local scattering process is wave-particle interactions with chorus. We find that anomalous radial diffusion can exceed that of conventional drift-resonant radial diffusion for particles with energies near 0.1 MeV at all radial distances outside the plasmasphere during quiet to moderate geomagnetic activity, and it is significant at 0.5 MeV. Cross diffusion involving the radial invariant can exceed the geometric mean of the corresponding pure diffusion coefficients at 0.1 MeV, and that such cross diffusion is significant even at 0.5-1 MeV. At 1 MeV, cross diffusion is often significant. The highest radial distances and magnetic activity levels in our study do not always exhibit as much significant anomalous diffusion as moderate radial distances and activity levels. This can be explained by (a) stronger dependence of conventional diffusion on magnetic activity and radius, and (b) strongest drift shell splitting at moderate magnetic activity. Simulation codes that neglect the possibility for cross terms will likely systematically underperform, especially for 0.1-0.5 MeV electrons, for much of the outer zone for quiet to moderate levels of magnetic activity.
Institute of Scientific and Technical Information of China (English)
Liu Xue-Chao; Chen Zhi-Zhan; Shi Er-Wei; Liao Da-Qian; Zhou Ke-Jin
2011-01-01
This paper reports that the (Ga, Co)-codoped ZnO thin films have been grown by inductively coupled plasma enhanced physical vapour deposition. Room-temperature ferromagnetism is observed for the as-grown thin films. The x-ray absorption fine structure characterization reveals that Co2+ and Ga3+ ions substitute for Zn2+ ions in the ZnO lattice and exclude the possibility of extrinsic ferromagnetism origin. The ferromagnetic (Ga, Co)-codoped ZnO thin films exhibit carrier concentration dependent anomalous Hall effect and positive magnetoresistance at room temperature. The mechanism of anomalous Hall effect and magneto-transport in ferromagnetic ZnO-based diluted magnetic semiconductors is discussed.
Phase-Transition and Magnetic Moment of the Gd3+ Ion in the Gd2Fe17 Compound
Institute of Scientific and Technical Information of China (English)
HAO Yan-Ming; FU Bin; ZHOU Yan; ZHAO Miao
2009-01-01
The structure and magnetic phase transitions of the Gd2Fe17 compound are investigated by using a differential thermal/thermogravimetric analyzer, x-ray diffraction, and magnetization measurements. The result shows that there are two phase structures for the Gd2Fe17 compound: the hexagonal Th2Ni17-type structure at high tem-peratures (above 1243℃), and the rhombohedrai Th2Zn17-type structure, respectively. A method to measure the magnetic moments of the Gd-sublattice and the Fe-sublattice in the Gd2Fe17 compound is presented. The moments of the Gd-sublattice and the Fe-sublattice in the Gd2Fe17 compound from 77 to 500 K are measured in this way with a vibrating sample magnetometer. A detailed discussion is presented.
Das, Chinmoy; Vaidya, Shefali; Gupta, Tulika; Frost, Jamie M; Righi, Mattia; Brechin, Euan K; Affronte, Marco; Rajaraman, Gopalan; Shanmugam, Maheswaran
2015-10-26
Three cationic [Ln4 ] squares (Ln=lanthanide) were isolated as single crystals and their structures solved as [Dy4 (μ4 -OH)(HL)(H2 L)3 (H2 O)4 ]Cl2 ⋅(CH3 OH)4 ⋅(H2 O)8 (1), [Tb4 (μ4 -OH)(HL)(H2 L)3 (MeOH)4 ]Cl2 ⋅(CH3 OH)4 ⋅(H2 O)4 (2) and [Gd4 (μ4 -OH)(HL)(H2 L)3 (H2 O)2 (MeOH)2 ]Br2 ⋅(CH3 OH)4 ⋅(H2 O)3 (3). The structures are described as hydroxo-centered squares of lanthanide ions, with each edge of the square bridged by a doubly deprotonated H2 L(2-) ligand. Alternating current magnetic susceptibility measurements show frequency-dependent out-of-phase signals with two different thermally assisted relaxation processes for 1, whereas no maxima in χM " appears above 2.0 K for complex 2. For 1, the estimated effective energy barrier for these two relaxation processes is 29 and 100 K. Detailed ab initio studies reveal that complex 1 possesses a toroidal magnetic moment. The ab initio calculated anisotropies of the metal ions in complex 1 were employed to simulate the magnetic susceptibility by using the Lines model (POLY_ANISO) and this procedure yields J1 =+0.01 and J2 =-0.01 cm(-1) for 1 as the two distinct exchange interactions between the Dy(III) ions. Similar parameters are also obtained for complex 1 (and 2) from specific heat measurements. A very weak antiferromagnetic super-exchange interaction (J1 =-0.043 cm(-1) and g=1.99) is observed between the metal centers in 3. The magnetocaloric effect (MCE) was estimated by using field-dependent magnetization and temperature-dependent heat-capacity measurements. An excellent agreement is found for the -ΔSm values extracted from these two measurements for all three complexes. As expected, 3 shows the largest -ΔSm variation (23 J Kg(-1) K(-1) ) among the three complexes. The negligible magnetic anisotropy of Gd indeed ensures near degeneracy in the (2S+1) ground state microstates, and the weak super-exchange interaction facilitates dense population of low-lying excited states, all of
Postma, H; Heyde, K; Walker, P; Grant, I; Veskovic, M; Stone, N; Stone, J
2002-01-01
% IS301 \\\\ \\\\ Low temperature nuclear orientation of isotope-separator implanted short-lived radioisotopes makes possible the measurements of nuclear magnetic dipole moments of oriented ground and excited states with half-lives longer than a few seconds. Coupling schemes characterizing the odd nucleons and ground-state deformations can be extracted from the nuclear moments. \\\\ We thus propose to measure the magnetic dipole moments of $^{127-133}$Sb to high precision using NMR/ON at the NICOLE facility. With (double magic +1) $^{133}$Sb as the reference, the main aim of this experiment is to examine whether the collective component in the 7/2$^+$ Sb ground state magnetic dipole moment varies as expected according to particle-core coupling calculations carried out for the Sb (Z=51) isotopes. Comparison of the 1-proton-particle excitations in Sb to 1-proton-hole states in In nuclei will shed light on differences between particle and hole excitations as understood within the present model. Comparison of r...
Indian Academy of Sciences (India)
R C Patnaik; R K Das; R L Hota; G S Tripathi
2001-10-01
We present theoretical analyses of anisotropic lattice diamagnetism, magnetization due to magnetic ions and carrier spin-polarization in the diluted magnetic semiconductor, Pb1-EuTe. The lattice diamagnetism results from orbital susceptibility due to inter band effects and spin-orbit contributions. The spin-orbit contribution is found to be dominant. However, both the contributions show pronounced anisotropy. With increase inx, the diamagnetism decreases. We consider contributions from randomly distributed isolated magnetic ions and clusters of pairs and triads for the local moment magnetization. The isolated magnetic-ion contribution is the dominant one. We calculate the magnetization for two typical magnetic ion concentrations: = 0.03 and = 0.06. Temperature dependence of the magnetization is also considered. Apart from lattice and localized magnetic ions, the carrier contribution to the spin-density is also calculated for a carrier density of = 1018 cm-3. The relative spin-density of carriers increases with increase in the magnetic ﬁeld strength and magnetic ion concentration. The agreement with experiment where available is reasonably good.
CP-violating effect of the Th nuclear magnetic quadrupole moment: accurate many-body study of ThO.
Skripnikov, L V; Petrov, A N; Titov, A V; Flambaum, V V
2014-12-31
Investigations of CP violation in the hadron sector may be done using measurements in the ThO molecule. Recent measurements in this molecule improved the limit on the electron electric dipole moment (EDM) by an order of magnitude. Another time-reversal (T) and parity (P)-violating effect in 229ThO is induced by the nuclear magnetic quadrupole moment. We perform nuclear and molecular calculations to express this effect in terms of the strength constants of T, P-odd nuclear forces, neutron EDM, QCD vacuum angle θ, quark EDM, and chromo-EDM. PMID:25615324
Magnetic Moments of the 21+ and 41+ States in 110SN
Kumbartzki, Gerfried; Benczer-Koller, N.; Bernstein, L.; Torres, D. A.; Speidel, K.-H.; Allmond, J. M.; Fallon, P.; Abramovic, I.; Bevins, J. M.; Hurst, A.; Guevara, Z. E.; Gürdal, G.; Kirsch, L.; Laplace, T.; Lo, A.; Crawford, H. L.; Matthew, E.; Meyers, I.; Phair, L.; Ramirez, F.; Sharon, Y. Y.; Wiens, A.
2015-10-01
The structure of the Sn isotopes has been studied via measurements of B(E2;21+->01+) transition rates and g factors of 21+ states. Values of B(E2)'s in the lighter isotopes show an increase in collectivity below midshell, contrary to predictions from shell model calculations. In order to better establish the structure of these neutron-deficient isotopes, measurements of g factors in 110Sn, where the neutrons might occupy both the g7 / 2 and d5 / 2 orbitals, have been carried out. The states of interest were populated in the reaction 12C(106Cd, 2 α)110Sn, at the LBNL 88 inch cyclotron. The γ rays were detected in ORNL and LBNL clover detectors. The transient field technique was used to obtain magnetic moments. The details of the experiment and the results will be presented. The authors acknowledge support from the US NSF and DoE, the Colombia Colciencias and the German DFG.
Macroscopic kinematics of the Hall electric field under influence of carrier magnetic moments
Sakai, Masamichi
2016-06-01
The relativistic effect on electromagnetic forces yields two types of forces which depend on the velocity of the relevant particles: (i) the usual Lorentz force exerted on a moving charged particle and (ii) the apparent Lorentz force exerted on a moving magnetic moment. In sharp contrast with type (i), the type (ii) force originates due to the transverse field induced by the Hall effect (HE). This study incorporates both forces into a Drude-type equation with a fully spin-polarized condition to investigate the effects of self-consistency of the source and the resultant fields on the HE. We also examine the self-consistency of the carrier kinematics and electromagnetic dynamics by simultaneously considering the Drude type equation and Maxwell equations at low frequencies. Thus, our approach can predict both the dc and ac characteristics of the HE, demonstrating that the dc current condition solely yields the ordinary HE, while the ac current condition yields generation of both fundamental and second harmonic modes of the HE field. When the magnetostatic field is absent, the simultaneous presence of dc and ac longitudinal currents generates the ac HE that has both fundamental frequency and second harmonic.
Macroscopic kinematics of the Hall electric field under influence of carrier magnetic moments
Directory of Open Access Journals (Sweden)
Masamichi Sakai
2016-06-01
Full Text Available The relativistic effect on electromagnetic forces yields two types of forces which depend on the velocity of the relevant particles: (i the usual Lorentz force exerted on a moving charged particle and (ii the apparent Lorentz force exerted on a moving magnetic moment. In sharp contrast with type (i, the type (ii force originates due to the transverse field induced by the Hall effect (HE. This study incorporates both forces into a Drude-type equation with a fully spin-polarized condition to investigate the effects of self-consistency of the source and the resultant fields on the HE. We also examine the self-consistency of the carrier kinematics and electromagnetic dynamics by simultaneously considering the Drude type equation and Maxwell equations at low frequencies. Thus, our approach can predict both the dc and ac characteristics of the HE, demonstrating that the dc current condition solely yields the ordinary HE, while the ac current condition yields generation of both fundamental and second harmonic modes of the HE field. When the magnetostatic field is absent, the simultaneous presence of dc and ac longitudinal currents generates the ac HE that has both fundamental frequency and second harmonic.
Energy Technology Data Exchange (ETDEWEB)
Chen, Zhi-Yuan [School of Nuclear Technology and Chemistry and Biology, Hubei University of Science and Technology, Xianning 437100 (China); Xu, Bin [Department of Mathematics and Information Sciences, North China Institute of Water Conservancy and Hydroelectric Power, Zhengzhou 450011 (China); Gao, G.Y., E-mail: guoying_gao@mail.hust.edu.cn [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China)
2013-12-15
The structural, electronic and magnetic properties of zinc-blende TiBi are investigated by using the first-principles full-potential linearized augmented plane-wave method. It is found that zinc-blende TiBi exhibits half-metallic ferromagnetism with the energy gap of 1.39 eV in the minority-spin channel. The calculated total magnetic moment of 1.00 µ{sub B} per formula unit mainly originates from the Ti atom. We also show that the half-metallicity of zinc-blende TiBi can be maintained up to 3% compression and 5% expansion of lattice constant with respect to the equilibrium lattice, and zinc-blende TiBi is still half-metallic when the spin–orbit coupling is considered. The robust half-metallicity and low magnetic moment make zinc-blende TiBi a potential candidate for spintronic applications. - Highlights: • Half-metallic ferromagnetism in zinc-blende TiBi. • Zinc-blende TiBi has low magnetic moment of 1.00 µ{sub B}/f.u. • Spin–orbit coupling does not destroy the half-metallicity of zinc-blende TiBi.
Afach, S; Ban, G; Bison, G; Bodek, K; Chowdhuri, Z; Daum, M; Fertl, M; Franke, B; Geltenbort, P; Green, K; van der Grinten, M G D; Grujic, Z; Harris, P G; Heil, W; Hélaine, V; Henneck, R; Horras, M; Iaydjiev, P; Ivanov, S N; Kasprzak, M; Kermaïdic, Y; Kirch, K; Knowles, P; Koch, H -C; Komposch, S; Kozela, A; Krempel, J; Lauss, B; Lefort, T; Lemière, Y; Mtchedlishvili, A; Naviliat-Cuncic, O; Pendlebury, J M; Piegsa, F M; Pignol, G; Prashant, P N; Quéméner, G; Rebreyend, D; Ries, D; Roccia, S; Schmidt-Wellenburg, P; Severijns, N; Weis, A; Wursten, E; Wyszynski, G; Zejma, J; Zenner, J; Zsigmond, G
2015-01-01
We report on the measurement of a Larmor frequency shift proportional to the electric-field strength for $^{199}{\\rm Hg}$ atoms contained in a volume permeated with aligned magnetic and electric fields. This shift arises from the interplay between the inevitable magnetic field gradients and the motional magnetic field. The proportionality to electric-field strength makes it apparently similar to an electric dipole moment (EDM) signal, although unlike an EDM this effect is P- and T-conserving. We have used a neutron magnetic resonance EDM spectrometer, featuring a mercury co-magnetometer and an array of external cesium magnetometers, to measure the shift as a function of the applied magnetic field gradient. Our results are in good agreement with theoretical expectations.
Afach, S.; Baker, C. A.; Ban, G.; Bison, G.; Bodek, K.; Chowdhuri, Z.; Daum, M.; Fertl, M.; Franke, B.; Geltenbort, P.; Green, K.; van der Grinten, M. G. D.; Grujic, Z.; Harris, P. G.; Heil, W.; Hélaine, V.; Henneck, R.; Horras, M.; Iaydjiev, P.; Ivanov, S. N.; Kasprzak, M.; Kermaïdic, Y.; Kirch, K.; Knowles, P.; Koch, H.-C.; Komposch, S.; Kozela, A.; Krempel, J.; Lauss, B.; Lefort, T.; Lemière, Y.; Mtchedlishvili, A.; Naviliat-Cuncic, O.; Pendlebury, J. M.; Piegsa, F. M.; Pignol, G.; Prashant, P. N.; Quéméner, G.; Rebreyend, D.; Ries, D.; Roccia, S.; Schmidt-Wellenburg, P.; Severijns, N.; Weis, A.; Wursten, E.; Wyszynski, G.; Zejma, J.; Zenner, J.; Zsigmond, G.
2015-10-01
We report on the measurement of a Larmor frequency shift proportional to the electric-field strength for 199Hg atoms contained in a volume permeated with aligned magnetic and electric fields. This shift arises from the interplay between the inevitable magnetic field gradients and the motional magnetic field. The proportionality to electric-field strength makes it apparently similar to an electric dipole moment (EDM) signal, although unlike an EDM this effect is P- and T-conserving. We have used a neutron magnetic resonance EDM spectrometer, featuring a mercury co-magnetometer and an array of external cesium magnetometers, to measure the shift as a function of the applied magnetic field gradient. Our results are in good agreement with theoretical expectations.
Energy Technology Data Exchange (ETDEWEB)
Meinert, M.; Schmalhorst, J; Klewe, C.; Reiss, G.; Arenholz, E.; Bohnert, T.; Nielsch, K.
2011-08-08
Epitaxial thin films of the half-metallic X{sub a}-compound Mn{sub 2}CoGa (Hg{sub 2}CuTi prototype) were prepared by dc magnetron co-sputtering with different heat treatments on MgO (001) substrates. High-quality lms with a bulk magnetization of 1.95(5) {mu}{sub }B per unit cell were obtained. The average Mn magnetic moment and the Co moment are parallel, in agreement with theory. The x-ray magnetic circular dichroism spectra agree with calculations based on density functional theory and reveal the antiparallel alignment of the two inequivalent Mn moments. X-ray magnetic linear dichroism allows to distinguish between itinerant and localized Mn moments. It is shown that one of the two Mn moments has localized character, whereas the other Mn moment and the Co moment are itinerant.
Salem-Sugui, Jr., S.; Alvarenga, A. D.; R. D. Noce; Mejia, C. Salazar; Salim, H.; Gandra, F. G.
2010-01-01
We report on an anomalous magnetization observed with temperature for low magnetic fields applied in the plane of a film formed by a thin layer of Fe-Rh deposited on a thin foil of ordered Fe$_3$Pt. The anomalous effect resembles a metamagnetic transition and occur only in the field-cooled-cooling magnetization curve at temperatures near 120 K. We also observe an aging effect which broads the metamagnetic-like transition suggesting the existence of Fe-Rh antiferromagnetic clusters which appar...
Directory of Open Access Journals (Sweden)
M A Islam
2010-03-01
Full Text Available Electrodeposition of Fe-Ni thin films has been carried on copper substrate under various electrodeposition conditions from two simple and six complex baths. Sulfate baths composing of NiSO4. 7H2O, FeSO4.7H2O, H3BO3 and Na2SO4KEYWORDS: Anomalous Electrodeposition, Fe-Ni Coating, Complexing agent, Current Density, Magnetic Property. 1. INTRODUCTION Alloy electrodeposition technologies can extend tremendously the potential of electrochemical deposition processes to provide coatings that require unique mechanical, chemical and physical properties [1]. There has been a great research interest in the development and characterization of iron-nickel (Fe-Ni thin films due to their operational capacity, economic interest, magnetic and other properties [2]. Due to their unique low coefficient of thermal expansion (CTE and soft magnetic properties, Fe-Ni alloys have been used in industrial applications for over 100 years [3]. Typical examples of applications that are based on the low CTE of Fe-Ni alloys include: thermostatic bimetals, glass sealing, integrated circuit packaging, cathode ray tube, shadow masks, membranes for liquid natural gas tankers; applications based on the soft magnetic properties include: read-write heads for magnetic storage, magnetic actuators, magnetic shielding, high performance transformer cores. comprise the simple baths whereas complex baths were prepared by adding ascorbic acid, saccharin and citric acid in simple baths. The effect of bath composition, pH and applied current density on coating appearance, composition, morphology and magnetic property were studied. Wet chemical analysis technique was used to analyze the coating composition whereas SEM and VSM were used to study the deposit morphology and magnetic property respectively. Addition of complexing agents in plating baths suppressed the anomalous nature of Fe-Ni alloy electrodeposition. Coatings obtained from simple baths were characterized by coarse grained non
M A Islam
2010-01-01
Electrodeposition of Fe-Ni thin films has been carried on copper substrate under various electrodeposition conditions from two simple and six complex baths. Sulfate baths composing of NiSO4. 7H2O, FeSO4.7H2O, H3BO3 and Na2SO4KEYWORDS: Anomalous Electrodeposition, Fe-Ni Coating, Complexing agent, Current Density, Magnetic Property. 1. INTRODUCTION Alloy electrodeposition technologies can extend tremendously the potential of electrochemical deposition processes to provide coatings that require ...
Experimental search for anomalous spin-spin interactions
International Nuclear Information System (INIS)
This paper reports on a Cavendish-type torsion pendulum, having test masses with 2.5 x 1011 polarized electrons and attracting masses with 8 x 1023 polarized electrons, is used to search for an anomalous spin interaction of macroscopic range. Competition from magnetic forces is reduced by using ferrimagnetic Dy-Fe masses which exhibit orbital compensation of the electron spin magnetic moments. Combined with magnetic shielding, the sensitivity is 2 x 10-4 of the gravitational force. Fluctuations set the overall experimental limit at about 5 times this level. The authors' results set limits on electron spin interactions and on moments which are not of electromagnetic origin. In terms of a standard dipole-dipole form, the limit is 1.5 x 20-12 of the interaction strength between the magnetic moments of the electrons. Compared to previous results, this is a six-fold improvement
International Nuclear Information System (INIS)
We have calculated the theoretical lattice parameters, Bulk modulus, volume, energy, lattice parameters and magnetic moments for RB6 (R=La, Ce, Pr and Sm) of CaB6 type crystal structure with space group Pm3m using full potential linearized augmented plane wave (FP-LAPW) method. The bulk modulus was found to be 9.56 % higher for LaB6 and 2.4% lower for CeB6 compared to the experimental results Gupta et al. [4] and Ogita et al [5], Magnetic moments for LaB6, CeB6 were found in qualitative agreement with the earlier reported results. The results based on generalized gradient approximation (GGA) were found and compared with local spin density approximation (LSDA) results for CeB6 and SmB6 as well.
Z =50 core stability in 110Sn from magnetic-moment and lifetime measurements
Kumbartzki, G. J.; Benczer-Koller, N.; Speidel, K.-H.; Torres, D. A.; Allmond, J. M.; Fallon, P.; Abramovic, I.; Bernstein, L. A.; Bevins, J. E.; Crawford, H. L.; Guevara, Z. E.; Gürdal, G.; Hurst, A. M.; Kirsch, L.; Laplace, T. A.; Lo, A.; Matthews, E. F.; Mayers, I.; Phair, L. W.; Ramirez, F.; Robinson, S. J. Q.; Sharon, Y. Y.; Wiens, A.
2016-04-01
Background: The structure of the semimagic 50Sn isotopes were previously studied via measurements of B (E 2 ;21+→01+ ) and g factors of 21+ states. The values of the B (E 2 ;21+ ) in the isotopes below midshell at N = 66 show an enhancement in collectivity, contrary to predictions from shell-model calculations. Purpose: This work presents the first measurement of the 2 1+ and 4 1+ states' magnetic moments in the unstable neutron-deficient 110Sn. The g factors provide complementary structure information to the interpretation of the observed B (E 2 ) values. Methods: The 110Sn nuclei have been produced in inverse kinematics in an α -particle transfer reaction from 12C to 106Cd projectiles at 390, 400, and 410 MeV. The g factors have been measured with the transient field technique. Lifetimes have been determined from line shapes using the Doppler-shift attenuation method. Results: The g factors of the 21+ and 41+ states in 110Sn are g (21+) = +0.29(11) and g (41+) = +0.05(14), respectively. In addition, the g (41+) = +0.27(6) in 106Cd has been measured for the first time. A line-shape analysis yielded τ (110Sn ; 21+) = 0.81(10) ps and a lifetime of τ (110Sn ; 31-) = 0.25(5) ps was calculated from the fully Doppler-shifted γ line. Conclusions: No evidence has been found in 110Sn that would require excitation of protons from the closed Z =50 core.
Magnetic moment and lifetime measurements of Coulomb-excited states in 106Cd
Benczer-Koller, N.; Kumbartzki, G. J.; Speidel, K.-H.; Torres, D. A.; Robinson, S. J. Q.; Sharon, Y. Y.; Allmond, J. M.; Fallon, P.; Abramovic, I.; Bernstein, L. A.; Bevins, J. E.; Crawford, H. L.; Guevara, Z. E.; Hurst, A. M.; Kirsch, L.; Laplace, T. A.; Lo, A.; Matthews, E. F.; Mayers, I.; Phair, L. W.; Ramirez, F.; Wiens, A.
2016-09-01
Background: The Cd isotopes are well studied, but experimental data for the rare isotopes are sparse. At energies above the Coulomb barrier, higher states become accessible. Purpose: Remeasure and supplement existing lifetimes and magnetic moments of low-lying states in 106Cd. Methods: In an inverse kinematics reaction, a 106Cd beam impinging on a 12C target was used to Coulomb excite the projectiles. The high recoil velocities provide a unique opportunity to measure g factors with the transient-field technique and to determine lifetimes from lineshapes by using the Doppler-shift-attenuation method. Large-scale shell-model calculations were carried out for 106Cd. Results: The g factors of the 21+ and 41+ states in 106Cd were measured to be g (21+)=+0.398 (22 ) and g (41+)=+0.23 (5 ) . A lineshape analysis yielded lifetimes in disagreement with published values. The new results are τ (106Cd;21+)=7.0 (3 )ps and τ (106Cd;41+)=2.5 (2 )ps . The mean life τ (106Cd;22+)=0.28 (2 )ps was determined from the fully-Doppler-shifted γ line. Mean lives of τ (106Cd;43+)=1.1 (1 )ps and τ (106Cd;31-)=0.16 (1 )ps were determined for the first time. Conclusions: The newly measured g (41+) of 106Cd is found to be only 59% of the g (21+) . This difference cannot be explained by either shell-model or collective-model calculations.
A set of sum rules for anomalous gauge boson couplings
Papavassiliou, J; Papavassiliou, Joannis; Philippides, Kostas
1999-01-01
The dependence of the differential cross-section for on-shell W-pair production on the anomalous trilinear gauge couplings invariant under C and P is examined. It is shown that the contributions of the anomalous magnetic moments of the W boson due to the photon and the Z can be individually projected out by means of two appropriately constructed polynomials. The remaining four anomalous couplings are shown to satisfy a set of model-independent sum rules. Specific models which predict special relations among the anomalous couplings are then studied; in particular, the composite model of Brodsky and Hiller, and the linear and non-linear effective Lagrangian approaches. The relations predicted by these models, when combined with the aforementioned sum rules, give rise to definite predictions, particular to each model. These predictions can be used, at least in principle, in order to exclude or constrain such models.
Magnetic moment for the negative parity Λ → Σ0 transition in light cone QCD sum rules
Aliev, T. M.; Savcı, M.
2016-07-01
The magnetic moment of the Λ →Σ0 transition between negative parity baryons is calculated in framework of the QCD sum rules approach by using the general form of the interpolating currents. The pollution arising from the positive-to-positive, and positive-to-negative parity baryons is eliminated by constructing the sum rules for different Lorentz structures. A comparison of our result with the predictions of the results of other approaches for the positive parity baryons is presented.
International Nuclear Information System (INIS)
A simple version of the cranked Hartree Fock Bogoliubov (CHFB) scheme that has been applied in the present research work is viewed to understand the level systematics in several nuclei. However the transition rates, static quadrupole and magnetic moments are not feasible in this scheme as angular momentum is generated on average in CHFB approach. But the gyromagnetic ratio (g) that is the expectation value of the orbital and spin angular momentum vectors can be calculated within this scheme
Schreider, A. A.; Ignatova, A. A.; Schreider, Al. A.; Sajneva, A. E.; Varga, P.; Denis, C.
2016-05-01
The VDM (virtual dipole moment) is one of the most significant characteristics describing the behavior of the time evolution of the terrestrial magnetic field. However, we have revealed that the formulas with which VDM calculations are performed often do not coincide with each other in various literature sources. Hence, results are obtained from these calculations that cannot be identical. Their correctness is verified by comparing the dimension and obtained results with the known value of the VDM for our time.
Neutron diffraction study of anomalous high-field magnetic phases in TmNi2B2C
DEFF Research Database (Denmark)
Toft, K.N.; Abrahamsen, A.B.; Eskildsen, M.R.;
2004-01-01
.90Yb0.10)Ni2B2C the Q(F)-->Q(AI) phase transition is also observed but at a larger transition field compared to the undoped compound. In (Tm0.85Yb0.15)Ni2B2C the Q(F) phase persists up to at least 1.8 T. The magnetic correlation length of the Q(AI) phase in TmNi2B2C measured parallel and perpendicular......We present a (B,T)-phase diagram of the magnetic superconductor TmNi2B2C obtained by neutron scattering. The measurements were performed in magnetic fields up to 6 T applied along the crystalline a axis. The observed phases are characterized by three ordering vectors, Q(F)=(0.094,0.094,0),Q(AI)=(0.......483,0,0), and Q(AII)=(0.496,0,0), all with the magnetic moment along the c axis. In zero and low fields the Tm 4f-moments order in a long wavelength transverse spin density wave with Q=Q(F). The magnetic Q(AI) structure is stabilized by an applied field of 1 T and a transition to Q(AII) is observed at 4 T...
Ultrafast dynamics of localized magnetic moments in the unconventional Mott insulator Sr2IrO4
Krupin, O.; Dakovski, G. L.; Kim, B. J.; Kim, J. W.; Kim, Jungho; Mishra, S.; Chuang, Yi-De; Serrao, C. R.; Lee, W.-S.; Schlotter, W. F.; Minitti, M. P.; Zhu, D.; Fritz, D.; Chollet, M.; Ramesh, R.; Molodtsov, S. L.; Turner, J. J.
2016-08-01
We report a time-resolved study of the ultrafast dynamics of the magnetic moments formed by the {{J}\\text{eff}}=1/2 states in Sr2IrO4 by directly probing the localized iridium 5d magnetic state through resonant x-ray diffraction. Using optical pump–hard x-ray probe measurements, two relaxation time scales were determined: a fast fluence-independent relaxation is found to take place on a time scale of 1.5 ps, followed by a slower relaxation on a time scale of 500 ps–1.5 ns.
Bialynicki-Birula, Iwo
2016-01-01
The motion of a neutral atom endowed with a magnetic moment interacting with the magnetic field is determined from the Ehrenfest-like equations of motion. These equations for the average values of the translational and spin degrees of freedom are derived from the Schr\\"odinger-Pauli wave equation and they form a set of nine coupled nonlinear evolution equations. The numerical and analytic solutions of these equations are obtained for the combination of the rotating magnetic field of a wave carrying orbital angular momentum and a static magnetic field. The running wave traps the atom only in the transverse direction while the standing wave traps the atom also in the direction of the beam.
Bialynicki-Birula, Iwo; RadoŻycki, Tomasz
2016-06-01
The motion of a neutral atom endowed with a magnetic moment interacting with the magnetic field is determined from the Ehrenfest-like equations of motion. These equations for the average values of the translational and spin degrees of freedom are derived from the Schrödinger-Pauli wave equation, and they form a set of nine coupled nonlinear evolution equations. The numerical and analytic solutions of these equations are obtained for the combination of the rotating magnetic field of a wave carrying orbital angular momentum and a static magnetic field. The running wave traps the atom only in the transverse direction, while the standing wave traps the atom also in the direction of the beam.
International Nuclear Information System (INIS)
The chiral magnetic wave is a gapless collective excitation of quark-gluon plasma in the presence of an external magnetic field that stems from the interplay of chiral magnetic and chiral separation effects; it is composed of the waves of the electric and chiral charge densities coupled by the axial anomaly. We consider a chiral magnetic wave at finite baryon density and find that it induces the electric quadrupole moment of the quark-gluon plasma produced in heavy ion collisions: the 'poles' of the produced fireball (pointing outside of the reaction plane) acquire additional positive electric charge, and the 'equator' acquires additional negative charge. We point out that this electric quadrupole deformation lifts the degeneracy between the elliptic flows of positive and negative pions leading to v2(π+)2(π-), and estimate the magnitude of the effect.
Induced magnetic moment on Rh in the (Fe{sub x}Rh{sub 1-x}){sub 100-y}B{sub y} amorphous system
Energy Technology Data Exchange (ETDEWEB)
Bhattacharya, Sarbari; Paulose, P.L. E-mail: paulose@tifr.res.in
2003-01-01
The magnetic properties of the (FeRh){sub 100-y}B{sub y}(y=20,25) amorphous system have been investigated by AC susceptibility, DC magnetization and {sup 57}Fe Moessbauer spectroscopy. The experimental data give strong evidence for the presence of a sizable moment on Rh. Our data suggest that the moment on Rh evolves discontinuously, existing only when it has at least four Fe nearest neighbours. While the condition for the appearance of the moment on Rh is identical in both the a-(FeRh){sub 75}B{sub 25} and a-(FeRh){sub 80}B{sub 20} systems, the magnitude of the induced moment decreases despite an enhancement in the average ferromagnetic exchange in the Boron-rich system. We show that the induced Rh moment is correlated to the Fe-Rh exchange and there are indications of induced moment on Rh even in the paramagnetic state.
Anomalous dimension, chiral phase transition and inverse magnetic catalysis in soft-wall AdS/QCD
Fang, Zhen
2016-07-01
A modified soft-wall AdS/QCD model with a z-dependent bulk scalar mass is proposed. We argue for the necessity of a modified bulk scalar mass from the quark mass anomalous dimension and carefully constrain the form of bulk mass by the corresponding UV and IR asymptotics. After fixing the form of bulk scalar mass, we calculate the mass spectra of (axial-)vector and pseudoscalar mesons, which have a good agreement with the experimental data. The behavior of chiral phase transition is also investigated, and the results are consistent with the standard scenario and lattice simulations. Finally, the issue of chiral magnetic effects is addressed. We find that the inverse magnetic catalysis emerges naturally from the modified soft-wall model, which is consistent with the recent lattice simulations.
Institute of Scientific and Technical Information of China (English)
LI Honghong; WANG Jie; LI Ruipeng; GUO Yuxian; WANG Feng; HU Zhiwei
2005-01-01
X-ray magnetic circular dichroism in absorption of the single-crystal iron layer deposited epitaxially on MgO substrate is studied. Spin and orbital moment, 0.069 and 2.33 -B, respectively, are calculated in terms of the XMCD sum rules. Our results are accordant to those published. Experiments show that the orbital moment would be decreased to that in bulk materials as iron film is thinned down, but spin moment changes little.
Biswas, Anirban; Choubey, Sandhya; Khan, Sarif
2016-01-01
The observation of neutrino masses, mixing and the existence of dark matter are amongst the most important signatures of physics beyond the Standard Model (SM). In this paper, we propose to extend the SM by a local $L_\\mu - L_\\tau$ gauge symmetry, two additional complex scalars and three right-handed neutrinos. The $L_\\mu - L_\\tau$ gauge symmetry is broken spontaneously when one of the scalars acquires a vacuum expectation value. The $L_\\mu - L_\\tau$ gauge symmetry is known to be anomaly free...
Heyrovska, R
2005-01-01
Sommerfeld introduced the fine-structure constant into physics, while he was taking into account the relativistic effects in the theory of the hydrogen atom. Ever since, it has puzzled many scientists like Eddington, Dirac, Feynman and others. Here the mysterious fine-structure constant, alpha = (Compton wavelength/de Broglie wavelength) = 1/137.036 = 2.627/360 is interpreted based on the finding that it is close to 2.618/360 = 1/137.508, where the Compton wavelength for hydrogen is a distance equivalent to an arc length on the circumference (given by the de Broglie wavelength) of a circle with the Bohr radius and 2.618 is the square of the Golden ratio, which was recently shown to divide the Bohr radius into two Golden sections at the point of electrical neutrality. From the data for the electron (e) and proton (p) g-factors, it is found that (137.508 - 137.036)= 0.472 = [g(p) - g(e)]/[g(p) + g(e)] (= 2/cube of the Golden ratio), and that (2.627 - 2.618)/360 = (small part of the Compton wavelength correspond...
Heyrovska, R.; Narayan, S
2005-01-01
Sommerfeld introduced the fine-structure constant into physics, while he was taking into account the relativistic effects in the theory of the hydrogen atom. Ever since, it has puzzled many scientists like Eddington, Dirac, Feynman and others. Here the mysterious fine-structure constant, alpha = (Compton wavelength/de Broglie wavelength) = 1/137.036 = 2.627/360 is interpreted based on the finding that it is close to 2.618/360 = 1/137.508, where the Compton wavelength for hydrogen is a distanc...
Energy Technology Data Exchange (ETDEWEB)
Duong, Le Quy; Das, Tanmoy; Feng, Y. P.; Lin, Hsin, E-mail: nilnish@gmail.com [Graphene Research Centre and Department of Physics, National University of Singapore, Singapore 117546 (Singapore)
2015-05-07
We study the evolution of quantum anomalous Hall (QAH) effect for a Z{sub 2} topological insulator (TI) thin films in a proximity induced magnetic phase by a realistic layered k·p model with interlayer coupling. We examine three different magnetic configurations in which ferromagnetic (FM) layer(s) is added either from one side (FM-TI), from both sides (FM-TI-FM), or homogeneously distributed (magnetically doped) in a TI slab. We map out the thickness-dependent topological phase diagram under various experimental conditions. The critical magnetic exchange energy for the emergence of QAH effect in the latter two cases decreases monotonically with increasing number of quintuple layers (QLs), while it becomes surprisingly independent of the film thickness in the former case. The gap size of the emergent QAH insulator depends on the non-magnetic “parent” gap of the TI thin film and is tuned by the FM exchange energy, opening a versatile possibility to achieve room-temperature QAH insulator in various topological nanomaterials. Finally, we find that the emergent spin-texture in the QAH effect is very unconventional, non-“hedgehog” type; and it exhibits a chiral out-of-plane spin-flip texture within the same valence band which is reminiscent of dynamical “skyrmion” pattern, except our results are in the momentum space.
Bounds on the electromagnetic dipole moments through the single top production at the CLIC
Koksal, M; Gutierrez-Rodriguez, A
2016-01-01
We obtain bounds on the anomalous magnetic and electric dipole moments of the $t$-quark from a future high-energy and high-luminosity linear electron positron collider, such as the CLIC, with unpolarized and polarized electron beams which are a powerful tool to determine new physics. We consider the processes $\\gamma e^- \\to \\bar t b\
AUTHOR|(CDS)2085887; Heylen, Hanne
In this work, the odd-even $^{51–63}$Mn isotopes have been analyzed using collinear laser spectroscopy, from which the magnetic dipole moment and the change in change in mean square charge radius can be determined. The magnetic moment is very sensitive to the composition of the total nuclear wave function, while the charge radius gives information about the relative size and degree of deformation of the nucleus. An additional advantage of collinear laser spectroscopy is the possibility of direct measurement of the nuclear spin. The main motivation behind the study of these isotopes is to investigate the change in nuclear structure when approaching neutron number N = 40. This region is of interest due to the apparent doubly magic nature of $^{68}$Ni , which is not seen in the N = 40 isotopes of $^{26}$Fe and $^{24}$Cr. Mn, situated between these elements, offers another perspective due to its uncoupled proton. Based on the observed spectra and extracted moments, spins were assigned to $^{59,61,63}$Mn. The ex...
International Nuclear Information System (INIS)
We developed a highly sensitive AC/DC magnetometer using a high-temperature superconductor superconducting quantum interference device for the evaluation of magnetic nanoparticles in solutions. Using the developed system, we investigated the distribution of magnetic moments of iron oxide multi-core particles of 100 nm at various iron concentrations that are lower than 96 μg/ml by analyzing the measured magnetization curves. Singular value decomposition and non-regularized non-negative least-squares methods were used during the reconstruction of the distribution. Similar distributions were obtained for all concentrations, and the iron concentration could be determined from the measured magnetization curves. The measured harmonics upon the excitation of AC and DC magnetic fields curves agreed well with the harmonics simulated based on the reconstructed magnetization curves, implying that the magnetization curves of magnetic nanoparticles were successfully obtained as we will show in the article. We compared the magnetization curves between multi-core particles of 100 nm and 130 nm, composed of 12-nm iron oxide nanoparticles. A distinctive magnetic property between the 100 nm and 130 nm particles in low-concentration solutions was successfully characterized. The distribution characteristic of magnetic moments suggests that the net magnetic moment in a multi-core particle is affected by the size of the magnetic cores and their degree of aggregation. Exploration of magnetic properties with high sensitivity can be expected using the developed system
Gutiérrez-Rodríguez, A; Noriega, L N Luis
2004-01-01
Limits on the anomalous magnetic moment and the electric dipole moment of the $\\tau$ lepton are calculated through the reaction $e^{+}e^{-}\\to \\tau^+ \\tau^- \\gamma$ at the $Z_1$-pole and in the framework of a left-right symmetric model. The results are based on the recent data reported by the L3 Collaboration at CERN LEP. Due to the stringent limit of the model mixing angle $\\phi$, the effect of this angle on the dipole moments is quite small.
Energy Technology Data Exchange (ETDEWEB)
Bierenbaum, I.; Bluemlein, J.; Klein, S.
2009-04-15
We calculate the O({alpha}{sub s}{sup 3}) heavy flavor contributions to theWilson coefficients of the structure function F{sub 2}(x,Q{sup 2}) and the massive operator matrix elements (OMEs) for the twist-2 operators of unpolarized deeply inelastic scattering in the region Q{sup 2}>>m{sup 2}. The massive Wilson coefficients are obtained as convolutions of massive OMEs and the known light flavor Wilson coefficients. We also compute the massive OMEs which are needed to evaluate heavy flavor parton distributions in the variable flavor number scheme (VFNS) to 3-loop order. All contributions to the Wilson coefficients and operator matrix elements but the genuine constant terms at O({alpha}{sub s}{sup 3}) of the OMEs are derived in terms of quantities, which are known for general values in the Mellin variable N. For the operator matrix elements A{sup (3)}{sub Qg}, A{sup (3)}{sub gq,Q} and A{sup (3)}{sub gg,Q} the moments N=2 to 10, for A{sup (3),PS}{sub Qq} to N=12, and for A{sup (3),NS}{sub qq,Q}, A{sup (3),PS}{sub qq,Q}, A{sup (3),PS}{sub gq,Q} to N=14 are computed. These terms contribute to the light flavor +-combinations. For the flavor non-singlet terms, we calculate as well the odd moments N=1 to 13, corresponding to the light flavor --combinations. We also obtain the moments of the 3-loop anomalous dimensions, their color projections for the present processes respectively, in an independent calculation, which agree with the results given in the literature. (orig.)
Tabar, Emre; Yakut, Hakan; Kuliev, Ali Akbar
2016-07-01
The ground state magnetic moments and the low-lying magnetic dipole (Ml) transitions from the ground to excited states in heavy deformed odd-mass 181Ta have been microscopically investigated on the basis of the quasiparticle-phonon nuclear model (QPNM). The problem of the spurious state mixing in M1 excitations is overcome by a restoration method allowing a self-consistent determination of the separable effective restoration forces. Due to the self-consistency of the method, these effective forces contain no arbitrary parameters. The results of calculations are compared with the available experimental data, the agreement being reasonably satisfactory.
Energy Technology Data Exchange (ETDEWEB)
Ouedraogo, Serge Aristide [Louisiana State Univ., Baton Rouge, LA (United States)
2008-12-01
A search for the muon neutrino magnetic moment was conducted using the Mini-BooNE low energy neutrino data. The analysis was performed by analyzing the elastic scattering interactions of muon neutrinos on electrons. The analysis looked for an excess of elastic scattering events above the Standard Model prediction from which a limit on the neutrino magnetic could be set. In this thesis, we report an excess of 15.3 ± 6.6(stat)±4.1(syst) v_{μ}e events above the expected background. At 90% C.L., we derived a limit on the muon neutrino magnetic moment of 12.7 x 10^{-10} μ_{B}. The other analysis reported in this thesis is a measurement of charged current single pion production (CCπ^{+}) to charged current quasi elastic (CCQE) interactions cross sections ratio. This measurement was performed with two different fitting algorithms and the results from both fitters are consistent with each other.
A review of high magnetic moment thin films for microscale and nanotechnology applications
Scheunert, G.; Heinonen, O.; Hardeman, R.; Lapicki, A.; Gubbins, M.; Bowman, R. M.
2016-01-01
The creation of large magnetic fields is a necessary component in many technologies, ranging from magnetic resonance imaging, electric motors and generators, and magnetic hard disk drives in information storage. This is typically done by inserting a ferromagnetic pole piece with a large magnetisation density MS in a solenoid. In addition to large MS, it is usually required or desired that the ferromagnet is magnetically soft and has a Curie temperature well above the operating temperature of ...
International Nuclear Information System (INIS)
A two-cascade magnetic field stabilizer for apparatus for the measurement of the neutron electric dipole moment (EDM) using ultracold neutrons was constructed and tested. Quantum cesium magnetometers (QCM) employing optical pumping and placed inside a multilayer magnetic screen were used as the magnetic field sensors. A static stabilization coefficient of 4 x 105 in the presence of magnetic noise of amplitude up to 50 nT was obtained using QCM employing the Ssub(z)-signal in the inner and outer cascades, their transfer ratios being 300 and 600, respectively. The mean square amplitude of the operating magnetic field fluctuations was 0.1 pT in the interval 10-4-10-2 Hz. Stabilization over a wider frequency band was obtained using QCM of the Ssub(z)-type in the inner cascade and of the Ssub(x)-type in the outer one. In particular, the mean square amplitude of the magnetic field fluctuations in the interval 0.1-1 Hz and 1-10 Hz were 1 pT and 15 pT, respectively. (orig.)
Gd-doped BaSnO{sub 3}: A transparent conducting oxide with localized magnetic moments
Energy Technology Data Exchange (ETDEWEB)
Alaan, Urusa S., E-mail: usalaan@gmail.com [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305 (United States); Shafer, Padraic; N' Diaye, Alpha T.; Arenholz, Elke [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Suzuki, Y. [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305 (United States); Department of Applied Physics, Stanford University, Stanford, California 94305 (United States)
2016-01-25
We have synthesized transparent, conducting, paramagnetic stannate thin films via rare-earth doping of BaSnO{sub 3}. Gd{sup 3+} (4f{sup 7}) substitution on the Ba{sup 2+} site results in optical transparency in the visible regime, low resistivities, and high electron mobilities, along with a significant magnetic moment. Pulsed laser deposition was used to stabilize epitaxial Ba{sub 0.96}Gd{sub 0.04}SnO{sub 3} thin films on (001) SrTiO{sub 3} substrates, and compared with Ba{sub 0.96}La{sub 0.04}SnO{sub 3} and undoped BaSnO{sub 3} thin films. Gd as well as La doping schemes result in electron mobilities at room temperature that exceed those of conventional complex oxides, with values as high as 60 cm{sup 2}/V·s (n = 2.5 × 10{sup 20 }cm{sup −3}) and 30 cm{sup 2}/V·s (n = 1 × 10{sup 20 }cm{sup −3}) for La and Gd doping, respectively. The resistivity shows little temperature dependence across a broad temperature range, indicating that in both types of films the transport is not dominated by phonon scattering. Gd-doped BaSnO{sub 3} films have a strong magnetic moment of ∼7 μ{sub B}/Gd ion. Such an optically transparent conductor with localized magnetic moments may unlock opportunities for multifunctional devices in the design of next-generation displays and photovoltaics.
Manz, Thomas A; Sholl, David S
2011-12-13
The partitioning of electron spin density among atoms in a material gives atomic spin moments (ASMs), which are important for understanding magnetic properties. We compare ASMs computed using different population analysis methods and introduce a method for computing density derived electrostatic and chemical (DDEC) ASMs. Bader and DDEC ASMs can be computed for periodic and nonperiodic materials with either collinear or noncollinear magnetism, while natural population analysis (NPA) ASMs can be computed for nonperiodic materials with collinear magnetism. Our results show Bader, DDEC, and (where applicable) NPA methods give similar ASMs, but different net atomic charges. Because they are optimized to reproduce both the magnetic field and the chemical states of atoms in a material, DDEC ASMs are especially suitable for constructing interaction potentials for atomistic simulations. We describe the computation of accurate ASMs for (a) a variety of systems using collinear and noncollinear spin DFT, (b) highly correlated materials (e.g., magnetite) using DFT+U, and (c) various spin states of ozone using coupled cluster expansions. The computed ASMs are in good agreement with available experimental results for a variety of periodic and nonperiodic materials. Examples considered include the antiferromagnetic metal organic framework Cu3(BTC)2, several ozone spin states, mono- and binuclear transition metal complexes, ferri- and ferro-magnetic solids (e.g., Fe3O4, Fe3Si), and simple molecular systems. We briefly discuss the theory of exchange-correlation functionals for studying noncollinear magnetism. A method for finding the ground state of systems with highly noncollinear magnetism is introduced. We use these methods to study the spin-orbit coupling potential energy surface of the single molecule magnet Fe4C40H52N4O12, which has highly noncollinear magnetism, and find that it contains unusual features that give a new interpretation to experimental data.
Description of anomalous Zeeman patterns in stellar astrophysics
Pain, Jean-Christophe
2013-01-01
The influence of a magnetic field on the broadening of spectral lines and transition arrays in complex spectra is investigated. The anomalous absorption or emission Zeeman pattern is a superposition of many profiles with different relative strengths, shifts, widths, asymmetries and sharpnesses. The "sigma" and "pi" profiles can be described statistically, using the moments of the Zeeman components. We present two statistical modellings: the first one provides a diagnostic of the magnetic field and the second one can be used to include the effect of a magnetic field on simulated atomic spectra in an approximate way.
Anomalous transport in toroidal plasmas
International Nuclear Information System (INIS)
When the magnetic moment of particle is conserved, there are three mechanisms which cause anomalous transport. These are: variation of magnetic field strength in flux surface, variation of electrostatic potential in flux surface, and destruction of flux surface. The anomalous transport of different groups of particles resulting from each of these mechanisms is different. This fact can be exploited to determine the cause of transport operative in an experimental situation. This approach can give far more information on the transport than the standard confinement time measurements. To implement this approach, we have developed Monte Carlo codes for toroidal geometries. The equations of motion are developed in a set of non-canonical, practical Boozer co-ordinates by means of Jacobian transformations of the particle drift Hamiltonian equations of motion. Effects of collisions are included by appropriate stochastic changes in the constants of motion. Effects of the loop voltage on particle motions are also included. We plan to apply our method to study two problems: the problem of the hot electron tail observed in edge region of ZT-40, and the energy confinement time in TOKAPOLE II. For the ZT-40 problem three situations will be considered: a single mode in the core, a stochastic region that covers half the minor radius, a stochastic region that covers the entire plasma. A turbulent spectrum of perturbations based on the experimental data of TOKAPOLE II will be developed. This will be used to simulate electron transport resulting from ideal instabilities and resistive instabilities in TOKAPOLE II
Anomalous behavior of magnetostriction and magnetic ac-suseptibility of Gd1-xPrxCo5 polycrystals
Directory of Open Access Journals (Sweden)
A. Amirabadizadeh
2003-12-01
Full Text Available Magnetostriction and low field ac-susceptibility of polycrystalline Gd1-xPrxCo5 (x = 0, 0.1 and 0.5 alloys are measured in temperature region of 77-300 K. XRD patterns show that our samples are single phase. For x = 0 (GdCo5 there are no anomaly in temperature dependence of magnetostriction and ac-susceptibility curves. For x = 0.1 and 0.5 temperature dependence of ac-susceptibilities show easy-axes phase transitions. In the case of x = 0.1 sample, the easy-axes of magnetization changes from canted to axial (practically, hexagonal c-axis direction as temperature increases, and ac-susceptibility of x = 0.5 sample shows two iterative transitions, first from basal to canted then canted to axial. Magnetostriction of Pr contained samples anomalously decreases at spin reorientation regions.
Energy Technology Data Exchange (ETDEWEB)
Barzakh, A. E., E-mail: barzakh@mail.ru; Fedorov, D. V.; Ivanov, V. S.; Mezilev, K. A.; Molkanov, P. L.; Moroz, F. V.; Orlov, S. Yu.; Panteleev, V. N.; Volkov, Yu. M. [NRC Kurchatov Institute, Petersburg Nuclear Physics Institute (PNPI) (Russian Federation)
2013-04-15
A new laser installation for the resonance ionization spectroscopy in a laser ion source and for rare isotope production has been put into operation at the IRIS mass-separator, working on-line with the 1 GeV proton beam of the Petersburg Nuclear Physics Institute synchrocyclotron. Isotope shift and hyperfine splitting of 276.9 nm atomic transition in the long chain of Tl isotopes and isomers have been measured. New data on the magnetic moments and changes in mean squared charge radius for {sup 183,184,185,185m,186m2,195m,197m}Tl have been obtained.
The lowest-lying spin-1/2 and spin-3/2 baryon magnetic moments in chiral perturbation theory
Geng, L S; Alvarez-Ruso, L; Vicente-Vacas, M J
2010-01-01
We review some recent progress in our understanding of the lowest-lying spin-1/2 and spin-3/2 baryon magnetic moments (MMs) in terms of Chiral Perturbation Theory (ChPT). In particular, we show that at next-to-leading-order ChPT can describe the MMs of the octet baryons quite well. We also make predictions for the decuplet MMs at the same chiral order. Among them, the MMs of the $\\Delta^{++}$ and $\\Delta^+$ are found to agree well with data within the experimental uncertainties.
Magnetic moment for the negative parity Λ→Σ0 transition in light cone QCD sum rules
Directory of Open Access Journals (Sweden)
T.M. Aliev
2016-07-01
Full Text Available The magnetic moment of the Λ→Σ0 transition between negative parity baryons is calculated in framework of the QCD sum rules approach by using the general form of the interpolating currents. The pollution arising from the positive-to-positive, and positive-to-negative parity baryons is eliminated by constructing the sum rules for different Lorentz structures. A comparison of our result with the predictions of the results of other approaches for the positive parity baryons is presented.
International Nuclear Information System (INIS)
A simple formulation for calculating the magnetic field external to an extended nonpermeable conducting body due to thermal current fluctuations within the body is developed, and is applied to a recent experimental search for the atomic electric-dipole moment (EDM) of 199Hg. It is shown that the thermal fluctuation field is only slightly smaller in magnitude than other noise sources in that experiment. The formulation is extended to permeable bodies, and the implications for general EDM experiments are discussed. copyright 1999 The American Physical Society
Harris, P G; Devenish, N E
2014-01-01
Trapped ultracold neutrons (UCN) have for many years been the mainstay of experiments to search for the electric dipole moment (EDM) of the neutron, a critical parameter in constraining scenarios of new physics beyond the Standard Model. Because their energies are so low, UCN preferentially populate the lower region of their physical enclosure, and do not sample uniformly the ambient magnetic field throughout the storage volume. This leads to a substantial increase in the rate of depolarization, as well as to shifts in the measured frequency of the stored neutrons. Consequences for EDM measurements are discussed.