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&...
KamLAND, solar antineutrinos and their magnetic moment
Aliani, P; Picariello, M; 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 a) the neutrino oscillates, only around 34% of the initial solar neutrinos arrive at the Earth as electron neutrinos and b) the conversion is mainly into active neutrinos, however a non e, mu, tau component is allowed: the fraction of oscillation into non-mu-tau neutrinos is found to be cos^2(alpha) = 0.08^{+0.20}_{-0.40}. This residual flux could include sterile neutrinos and/or the antineutrinos of the active flavors. KamLAND is potentially sensitive to antineutrinos derived from solar ^8 B neutrinos. In case of negative results, we find that KamLAND could put strict limits on the flux of solar antineutrinos, Phi(^8 B) < 1.0 times 10^4 cm^{-2} s^{-1}, more than one order of magnitude smaller than existing limits, and on their app...
We present research results of the preparation project for the experimental measurement of the (anti)neutrino magnetic moment at the level of 10-12 μB using an intense tritium source of antineutrinos and a liquid helium scintillation detector. The neutrino detection in the scintillation detector is based on the scattering of neutrinos by the electrons of the helium atoms that produces fast electrons able to ionize and exciting helium atoms. The detection of the atomic radiation emitted during the relaxation process of the helium atoms and the knowledge of its parameters will allow us to conclude on the neutrino properties
Martemyanov, V.P.; Aleshin, V.I.; Tarasenko, V.G.; Tsinoev, V.G.; Sabelnikov, A.A. [NRC Kurchatov Institute, Moscow (Russian Federation); Yukhimchuk, A.A.; Popov, V.V.; Baluev, V.V.; Golubkov, A.N.; Klevtsov, V.G.; Kuryakin, A.V.; Sitdikov, D.T. [RFNC VNIIEF, Sarov (Russian Federation); Bogdanova, L.N. [SSC RF ITEP, Moscow (Russian Federation)
2015-03-15
We present research results of the preparation project for the experimental measurement of the (anti)neutrino magnetic moment at the level of 10{sup -12} μ{sub B} using an intense tritium source of antineutrinos and a liquid helium scintillation detector. The neutrino detection in the scintillation detector is based on the scattering of neutrinos by the electrons of the helium atoms that produces fast electrons able to ionize and exciting helium atoms. The detection of the atomic radiation emitted during the relaxation process of the helium atoms and the knowledge of its parameters will allow us to conclude on the neutrino properties.
KamLAND, solar antineutrinos and the solar magnetic field
Chauhan, B C; Torrente-Lujan, E; Chauhan, Bhag C.; Pulido, Joao
2003-01-01
In this work the possibility of detecting solar electron antineutrinos produced by a solar core magnetic field from the KamLAND recent observations is investigated. We find 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 electron antineutrino spectrum can be unambiguosly predicted. We use this scaling and the negative results indicated by the KamLAND experiment to obtain upper bounds on the solar electron antineutrino flux. We get $\\phi_{\\bar\
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
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...
Semikoz, V B; Popov, V Yu; Rez, A I; Sokoloff, D D
2000-01-01
The magnetic field in the solar convective zone has a random small-scale component with the r.m.s. value substancially exceeding the strength of a regular large-scale field. For two Majorana neutrino flavors and two helicities in the presence of a neutrino transition magnetic moment and nonzero neutrino mixing we analize the displacement of the allowed (Delta m^2 - sin^2 2theta)-parameter region reconciled for all Underground experiments with solar neutrinos in dependence on the r.m.s. magnetic field value b. In contrary with the RSFP scenario with a regular large-scale magnetic field, we find an effective production of electron antineutrinos in the Sun even for small neutrino mixing through the cascade conversions like nu_eL -> \\bar{nu}_muR -> forbidden while opening LOW MSW as the allowed one from the non-observation of 100 kG and correlation lengths shorter than L_0 < 1000 km.
Impulse approximation and pion-exchange current contributions to the trinucleon magnetic moments are calculated using wave functions generated by solving the configuration-space Faddeev equations for a variety of nucleon-nucleon force models. Careful attention is paid to the origin of important exchange current contributions. Numerical results are compared with previously published calculations and with the experimental data. An attempt is made to isolate and understand sources of discrepancy between our results and those previously published. Calculations which include both impulse and pion-exchange current contributions are in fairly good agreement with experiment, whereas calculations which include only the impulse approximation term are not
The first result of the neutrino magnetic moment measurement in the GEMMA experiment
Beda, A G; Demidova, E V; Egorov, V G; Gavrilov, M G; Shirchenko, M V; Starostin, A S; Vylov, T
2007-01-01
The first result of the neutrino magnetic moment measurement at the Kalininskaya Nuclear Power Plant (KNPP) with the GEMMA spectrometer is presented. An antineutrino-electron scattering is investigated. A high-purity germanium detector of 1.5 kg placed 13.9 m away from the 3 GW reactor core is used in the spectrometer. The antineutrino flux is $2.73\\times 10^{13} \
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.
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.
Hyperon polarization and magnetic moments
Inclusively produced hyperons with significant polarization were first observed at Fermilab about seventeen years ago. This and subsequent experiments showed that Λ degree were produced polarized while bar Λ degree had no polarization in the same kinematical region. This set the stage for many experiments which showed that most hyperons are produced polarized. Recent Fermilab experiments have showed that this phenomena is even more complex and theoretical understanding is still lacking. Nevertheless polarized hyperon beams have been an extremely useful experimental tool in measuring hyperon magnetic moments. Recently, magnetic moment precession of channeled particles in bent crystals has been observed. This opens the possibility of measuring the magnetic moments of charmed baryons
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 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.
Updating neutrino magnetic moment constraints
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.
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.
GEMMA experiment: three years of the search for the neutrino magnetic moment
Beda, A G; Demidova, E V; Egorov, V G; Medvedev, D V; Shirchenko, M V; Starostin, A S; Vylov, Ts
2009-01-01
The result of the 3-year neutrino magnetic moment measurement at the Kalinin Nuclear Power Plant with the GEMMA spectrometer is presented. Antineutrino-electron scattering is investigated. A high-purity germanium detector of 1.5 kg placed at a distance of 13.9 m from the 3 GW(th) reactor core is used in the spectrometer. The antineutrino flux is 2.7E13 1/scm/s. The differential method is used to extract (nu-e) electromagnetic scattering events. The scattered electron spectra taken in 5184+6798 and 1853+1021 hours for the reactor ON and OFF periods are compared. The upper limit for the neutrino magnetic moment < 3.2E-11 Bohr magneton at 90% CL is derived from the data processing.
Upper limit on the neutrino magnetic moment from three years of data from the GEMMA spectrometer
Beda, A G; Egorov, V G; Medvedev, D V; Pogosov, V S; Shirchenko, M V; Starostin, A S
2010-01-01
The result of the 3-year neutrino magnetic moment measurement at the Kalinin Nuclear Power Plant with the GEMMA spectrometer is presented. Antineutrino-electron scattering is investigated. A HPGe detector of 1.5 kg placed at a distance of 13.9 m from the 3 GW_th reactor core is used in the spectrometer. The antineutrino flux is 2.7x10^13 1/cm^2/s. The differential method is used to extract nu-e electromagnetic scattering events. The scattered electron spectra taken in 5184+6798 and 1853+1021 hours for the reactor ON and OFF periods are compared. The upper limits at 90% CL for the neutrino magnetic moment with and without atomic ionization mechanism were found to be 5.0x10^-12 and 3.2x10^-11 Bohr magnetons, respectively.
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).
Prospects for Detecting a Neutrino Magnetic Moment with a Tritium Source and Beta-beams
McLaughlin, G. C.; Volpe, C.
2003-01-01
We compare the prospects for detecting a neutrino magnetic moment by the measurement of neutrinos from a tritium source, reactors and low-energy beta-beams. In all cases the neutrinos or antineutrinos are detected by scattering of electrons. We find that a large (20 MCurie) tritium source could improve the limit on the neutrino magnetic moment significantly, down to the level of a few $\\times 10^{-12}$ while low-energy beta-beams with sufficiently rapid production of ions could improve the li...
HELMHOLTZ COILS FOR MEASURING MAGNETIC MOMENTS
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.
Theory of nuclear magnetic moments - LT-35
The purpose of these notes is to give an account of some attempts at interpreting the observed values of nuclear magnetic moments. There is no attempt at a complete summary of the field as that would take much more space than is used here. In many cases the arguments are only outlined and references are given for those interested in further details. A discussion of the theory of nuclear magnetic moments necessitates many excursions into the details of the nuclear models because the magnetic moments have a direct bearing on the validity of these models. However the main emphasis here is on those features which tend to explain the magnetic moments and other evidence is not discussed unless it has a direct bearing on the problem. In the first part of the discussion the Shell Model of the nucleus is used, as this model seems to correlate a large body of data relating to the heavier nuclei. Included here are the modifications proposed to explain the fact that the experimental magnetic moments do not fit quantitatively with the exact predictions of the Shell Model. The next sections deal with some of the more drastic modifications introduced to explain the large nuclear quadrupole moments and the effect of these modifications on the magnetic moments. Finally we turn to more detailed investigations of the light nuclei, in particular the - Conjugate nuclei. (author)
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 measurement of magnetic nanoparticles using atomic force microscopy
Magnetic moment per unit mass of magnetic nanoparticles was found by using the atomic force microscope (AFM). The mass of the nanoparticles was acquired from the resonance frequency shift of the particle-attached AFM probe and magnetic force measurement was also carried out with the AFM. Combining with magnetic field strength, the magnetic moment per unit mass of the nanoparticles was determined as a function of magnetic field strength. (technical design note)
Magnetic moment of the Roper resonance
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.
Anomalous magnetic moment with heavy virtual leptons
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.
An experimental review of hyperon magnetic moments
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
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.
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....
Estimation of particle magnetic moment distribution for antiferromagnetic ferrihydrite nanoparticles
Magnetization as a function of applied magnetic field at different temperatures for antiferromagnetic nanoparticles of ferrihydrite is measured and analyzed considering a distribution in particle magnetic moment. We find that the magnetization of this nanoparticle system is affected by the presence of particle magnetic moment distribution. This particle magnetic moment distribution is estimated at different temperatures. - Highlights: • Magnetic behavior of a nanoparticle system is affected by the presence of particle magnetic moment distribution. • One can not get correct and physically meaningful fit parameters if the particle magnetic moment distribution is ignored. • This particle magnetic moment distribution using the magnetization data is estimated for 2 nm antiferromagnetic ferrihydrite particles
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.
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
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.
Prospects for Detecting a Neutrino Magnetic Moment with a Tritium Source and Beta-beams
McLaughlin, G C
2003-01-01
We compare the prospects for detecting a neutrino magnetic moment by the measurement of neutrinos from a tritium source, reactors and low-energy beta-beams. In all cases the neutrinos or antineutrinos are detected by scattering of electrons. We find that a large (20 MCurie) tritium source could improve the limit on the neutrino magnetic moment significantly, down to the level of a few $\\times 10^{-12}$ while low-energy beta-beams with sufficiently rapid production of ions could improve the limits to the level of a few $\\times 10^{-11}$. The latter would require ion production at the rate of at least $10^{15}$ s$^{-1}$.
Neutrino masses, magnetic moments, and horizontal symmetries
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.
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.
Nuclear Bag Model and Nuclear Magnetic Moments
Liu, Liang-Gang
1999-01-01
In 1991, we proposed a model in which nucleus is treated as a spherical symmetric MIT bag and nucleon satisfies the MIT bag model boundary condition. The model was employed to calculate nuclear magnetic moments. The results are in good agreement with experiment data. Now, we found this model is still interesting and illuminating.
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
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
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.
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
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
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.
The photon magnetic moment problem revisited
The photon magnetic moment for radiation propagating in magnetized vacuum is defined as a pseudotensor quantity, proportional to the external electromagnetic field tensor. After expanding the eigenvalues of the polarization operator in powers of k2, we obtain approximate dispersion equations (cubic in k2), and analytic solutions for the photon magnetic moment, valid for low momentum and/or large magnetic field. The paramagnetic photon experiences a redshift, with opposite sign to the gravitational one, which differs for parallel and perpendicular polarizations. It is due to the drain of photon transverse momentum and energy by the external field. By defining an effective transverse momentum, the constancy of the speed of light orthogonal to the field is guaranteed. We conclude that the propagation of the photon non-parallel to the magnetic direction behaves as if there is a quantum compression of the vacuum or a warp of space-time in an amount depending on its angle with regard to the field. (orig.)
Unstable magnetic moments in Ce compounds
The problems which are connected with the appearance or disappearance of local moments in metals are well reflected in the magnetic behaviour of Ce intermetallic compounds. This work describes experiments on two Ce compounds which are typical examples of unstable moment systems. The first of these is CeAl2 which at low temperatures, shows coexistence of antiferromagnetic order and the Kondo effect. Measurements are presented of the magnetization and the susceptibility in different magnetic field and temperature regions. An analysis of these measurements, using a model for the crystal field effects, shows the agreement between the measurements and the calculations to be reasonably good for CeAl2, but this agreement becomes worse upon decreasing Ce concentration. A phenomenological description of the observations is given. The second compound reported on is CeCu2Si2, the first 'heavy-fermion' superconductor to be investigated. The superconducting state is possibly formed by the quasi-particles of a non-magnetic many body singlet state, and not simply by the (sd) conduction electrons. This being a novel phenomenon, a number of experiments were performed to test this picture and to obtain a detailed description of the behaviour of CeCu2Si2. Measurements of the Meissner volume, confirmed the superconductivity to be intrinsic. (Auth.)
Strange magnetic moments of octet baryons under SU(3) breaking
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.
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
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 pz 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.
Shuffle dislocation induced magnetic moment in graphene
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.
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.
Quantum tunneling of the magnetic moment in a free nanoparticle
We study tunneling of the magnetic moment in a particle that has full rotational freedom. Exact energy levels are obtained and the ground-state magnetic moment is computed for a symmetric rotor. The effect of mechanical freedom on spin tunneling manifests itself in a strong dependence of the magnetic moment on the moments of inertia of the rotor. The energy of the particle exhibits quantum phase transitions between states with different values of the magnetic moment. Particles of various shapes are investigated and the quantum phase diagram is obtained. - Highlights: ► We obtain an exact analytical solution of a tunneling spin in a mechanical rotator. ► The quantum phase diagram shows magnetic moment dependence on rotator shape and size. ► Our work explains magnetic properties of free atomic clusters and magnetic molecules.
Energy of magnetic moment of superconducting current in magnetic field
Gurtovoi, V.L.; Nikulov, A.V., E-mail: nikulov@iptm.ru
2015-09-15
Highlights: • Quantization effects observed in superconducting loops are considered. • The energy of magnetic moment in magnetic field can not be deduced from Hamiltonian. • This energy is deduced from a history of the current state in the classical case. • It can not be deduced directly in the quantum case. • Taking this energy into account demolishes agreement between theory and experiment. - Abstract: The energy of magnetic moment of the persistent current circulating in superconducting loop in an externally produced magnetic field is not taken into account in the theory of quantization effects because of identification of the Hamiltonian with the energy. This identification misleads if, in accordance with the conservation law, the energy of a state is the energy expended for its creation. The energy of magnetic moment is deduced from a creation history of the current state in magnetic field both in the classical and quantum case. But taking this energy into account demolishes the agreement between theory and experiment. Impartial consideration of this problem discovers the contradiction both in theory and experiment.
Energy of magnetic moment of superconducting current in magnetic field
Highlights: • Quantization effects observed in superconducting loops are considered. • The energy of magnetic moment in magnetic field can not be deduced from Hamiltonian. • This energy is deduced from a history of the current state in the classical case. • It can not be deduced directly in the quantum case. • Taking this energy into account demolishes agreement between theory and experiment. - Abstract: The energy of magnetic moment of the persistent current circulating in superconducting loop in an externally produced magnetic field is not taken into account in the theory of quantization effects because of identification of the Hamiltonian with the energy. This identification misleads if, in accordance with the conservation law, the energy of a state is the energy expended for its creation. The energy of magnetic moment is deduced from a creation history of the current state in magnetic field both in the classical and quantum case. But taking this energy into account demolishes the agreement between theory and experiment. Impartial consideration of this problem discovers the contradiction both in theory and experiment
New method of determining the magnetic moment of the electron
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.
Sigma-lambda transition magnetic moment
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/
Magnetic moment non-conservation in magnetohydrodynamic turbulence models
Dalena, S; Rappazzo, A F; Mace, R L; Matthaeus, W H
2012-01-01
The fundamental assumptions of the adiabatic theory do not apply in presence of sharp field gradients as well as in presence of well developed magnetohydrodynamic turbulence. For this reason in such conditions the magnetic moment $\\mu$ 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 $\\Delta \\mu$ (defined as the half peak-to-peak difference in the particle magnetic moment) and the bounce frequency $\\omega_b$. We perform test-particle simulations to investigate magnetic moment behavior when resonances overlapping occurs and during the interaction of a ring-beam particle distribution with a broad-band slab spectrum. We find that magnetic moment dynamics is strictly related to pitch angle $\\alpha$ for a low level of magnetic fluctuation, $\\delta B/B_0...
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
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.
Octet baryon magnetic moments in light cone QCD sum rules
Aliev, T M; Özpineci, A
2002-01-01
Octet baryon magnetic moments are calculated in framework of the light cone QCD sum rules. The analysis is carried for the general form of the interpolating currents for octet baryons. A comparison of our results on the magnetic moments of octet baryons with the predictions of other approaches and experimental data is presented.
Magnetic moments of charm baryons in chiral perturbation theory
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.
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
Neutral fermion with magnetic moment in external electromagnetic fields
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
Fits combining hyperon semileptonic decays and magnetic moments and CVC
We have performed a test of CVC by determining the baryon charges and magnetic moments from the hyperon semileptonic data. Then CVC was applied in order to make a joint fit of all baryon semileptonic decay data and baryon magnetic moments for the spectrum generating group (SG) model as well as for the conventional (cabibbo and magnetic moments in nuclear magnetons) model. The SG model gives a very good fit with chi2/n/sub D/ = 25/20 approximately equals 21% C.L. whereas the conventional model gives a fit with chi2/n/sub D/ = 244/20
Millicharged neutrino with anomalous magnetic moment in rotating magnetized matter
Studenikin, Alexander
2014-01-01
We consider a millicharged neutrino with nonzero magnetic moment in the presence of rotating and magnetized background matter. The exact solution of the corresponding modified Dirac equation for the neutrino wave function is found. The neutrino energy spectrum is obtained and the effect of neutrino energy quantization is discussed in details. We introduce a new kind of spin operator which is a superposition of longitudinal and transverse polarizations operators for description of the neutrino spin properties in the considered background environment. Within the quasi-classical approach to the problem, radius of the neutrino orbits is derived and the effective "matter induced Lorentz force" is introduced. It is shown that in the considered environment, and also in matter with nonzero gradient of density, neutrino moves with acceleration. In this case a new type of the electromagnetic neutrino radiation (termed "light of millicharged neutrino") can be produced. The considered problem is of interest for astrophys...
Magnetic moment distributions in α-Fe nanowire array
LI; Fashen; (李发伸); REN; Liyuan; (任立元); NIU; Ziping; (牛紫平); WANG; Haixin; (王海新); WANG; Tao; (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.
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.
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.
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.
Composite Higgs Models, Technicolor and The Muon Anomalous Magnetic Moment
Doff, A.(Universidade Tecnológica Federal do Paraná – UTFPR – DAFIS, Av. Monteiro Lobato Km 04, 84016-210 Ponta Grossa, PR, Brazil); Clarissa Siqueira
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 stringen...
A note on the anomalous magnetic moment of the muon
Palle, Davor
2016-01-01
The anomalous magnetic moment of the muon is an important observable that tests radiative corrections of all three observed local gauge forces: electromagnetic, weak and strong interactions. High precision measurements reveal some discrepancy with the most accurate theoretical evaluations of the anomalous magnetic moment. We show in this note that the UV finite theory cannot resolve this discrepancy. We believe that more reliable estimate of the nonperturbative hadronic contribution and the new measurements can resolve the problem.
Magnetic dipole moments of the heavy tensor mesons in QCD
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
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., 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
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 and electric dipole moment of the τ-lepton
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
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.
KamLAND and Solar Antineutrino Spectrum
Chauhan, B C; Torrente-Lujan, E; Chauhan, Bhag C.; Pulido, Joao
2004-01-01
We use the recent KamLAND observations to predict the solar antineutrino spectrum at some confidence limits. We find that 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-- can be utilised to obtain a general shape of the solar antineutrino spectrum. This scaling and the upper bound on the solar antineutrino event rate, that can be derived from the data, lead to: 1) an upper bound on the solar antineutrino flux, 2) the prediction of their energy spectrum, as the normalisation of the spectrum can be obtained from the total number of antineutrino events recorded in the experiment. We get $\\phi_{\\bar\
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.
Dynamic interaction between localized magnetic moments in carbon nanotubes
Costa, A T; Muniz, R B [Instituto de FIsica, Universidade Federal Fluminense, 24210-346 Niteroi, RJ (Brazil); Ferreira, M S [School of Physics, Trinity College Dublin, Dublin 2 (Ireland)], E-mail: antc@if.uff.br, E-mail: bechara@if.uff.br, E-mail: ferreirm@tcd.ie
2008-06-15
Magnetic moments dilutely dispersed in a metallic host tend to be coupled through the conduction electrons of the metal. This indirect exchange coupling (IEC), known to occur for a variety of magnetic materials embedded in several different metallic structures, is of rather long range, especially for low-dimensional structures like carbon nanotubes. Motivated by recent claims that the indirect coupling between magnetic moments in precessional motion has a much longer range than its static counterpart, we consider here how magnetic atoms adsorbed to the walls of a metallic nanotube respond to a time-dependent perturbation that induces their magnetic moments to precess. By calculating the frequency-dependent spin susceptibility, we are able to identify resonant peaks whose respective widths provide information about the dynamic aspect of the IEC. We show that by departing from a purely static representation to another in which the moments are allowed to precess, we change from what is already considered a long-range interaction to another whose range is far superior. In other words, localized magnetic moments embedded in a metallic structure can feel each other's presence more easily when they are set in precessional motion. We argue that such an effect can have useful applications leading to large-scale spintronics devices.
Dynamic interaction between localized magnetic moments in carbon nanotubes
Magnetic moments dilutely dispersed in a metallic host tend to be coupled through the conduction electrons of the metal. This indirect exchange coupling (IEC), known to occur for a variety of magnetic materials embedded in several different metallic structures, is of rather long range, especially for low-dimensional structures like carbon nanotubes. Motivated by recent claims that the indirect coupling between magnetic moments in precessional motion has a much longer range than its static counterpart, we consider here how magnetic atoms adsorbed to the walls of a metallic nanotube respond to a time-dependent perturbation that induces their magnetic moments to precess. By calculating the frequency-dependent spin susceptibility, we are able to identify resonant peaks whose respective widths provide information about the dynamic aspect of the IEC. We show that by departing from a purely static representation to another in which the moments are allowed to precess, we change from what is already considered a long-range interaction to another whose range is far superior. In other words, localized magnetic moments embedded in a metallic structure can feel each other's presence more easily when they are set in precessional motion. We argue that such an effect can have useful applications leading to large-scale spintronics devices
Magnetic Moment of Vector Mesons in the Background Field Method
Lee, F X; Wilcox, Walter
2007-01-01
We report some results for the magnetic moments of vector mesons extracted from mass shifts in the presence of static external magnetic fields. The calculations are done on $24^4$ quenched lattices using standard Wilson actions, with $\\beta$=6.0 and pion mass down to 500 MeV. The results are compared to those from the form factor method.
Resonances and dipole moments in dielectric, magnetic, and magnetodielectric cylinders
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...
Neutrino magnetic moment and the solar neutrino problem
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
A new measurement of the Σ+ magnetic moment
A new measurement of the Σ+ magnetic moment is reported. The measurement stems from 12 000 events of the reaction K-p→Σ+π- produced at beam momenta around 460 MeV/c in HYBUC, the hydrogen bubble chamber with an 11.5 T magnetic field. These events represent about 15% of the final statistics. The results from opposite field directions are in close agreement and yield an average value of 2.95 +- 0.31 nuclear magnetons for the total Σ+ magnetic moment. (Auth.)
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.
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.
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.
The matrix 8-component Dirac-like form of the P-odd equations for boson fields of spin 1 and 0 are obtained and the GL(2,c) symmetry group of the 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 electric dipole moments and anomalous magnetic moments by an external constant and uniform electromagnetic field has been found using 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. (orig.)
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.
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
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 were 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 ...
Neutral current induced π0 production and neutrino magnetic moment
We have studied the total cross section, Q2, momentum and angular distributions for pions in the ν(ν) induced π0 production from nucleons. The calculations have been done for the weak production induced by the neutral current in the standard model and the electromagnetic production induced by neutrino magnetic moment. It has been found that with the present experimental limits on the muon neutrino magnetic moment μνμ, the electromagnetic contribution to the cross section for the π0 production is small. The neutrino induced neutral current production of π0, while giving an alternative method to study the magnetic moment of neutrino μνμ, does not provide any improvement over the present experimental limit on μνμ from the observation of this process in future experiments at T2K and NOνA.
Magnetic moment of a bound electron
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.
Effective particle magnetic moment of multi-core particles
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.
Fractional impurity moments in two-dimensional noncollinear magnets.
Wollny, Alexander; Fritz, Lars; Vojta, Matthias
2011-09-23
We study dilute magnetic impurities and vacancies in two-dimensional frustrated magnets with noncollinear order. Taking the triangular-lattice Heisenberg model as an example, we use quasiclassical methods to determine the impurity contributions to the magnetization and susceptibility. Most importantly, each impurity moment is not quantized but receives nonuniversal screening corrections due to local relief of frustration. At finite temperatures, where bulk long-range order is absent, this implies an impurity-induced magnetic response of Curie form, with a prefactor corresponding to a fractional moment per impurity. We also discuss the behavior in an applied magnetic field, where we find a singular linear-response limit for overcompensated impurities. PMID:22026900
From magnetic moment to general spin-isospin modes
Study of nuclear magnetic moments is historically reviewed. The first and second order configuration mixings, exhange currents, their interference and isobar currents are discussed. A unified view of the configuration mixings and the exchange currents is presented in connection with a single particle effective magnetic moment operator used in the shell model. Discussion is extended to general nuclear spin-isospin modes with finite energy momentum transfer. Emphasis is on the spin-isospin modes in the quasifree scattering region. Analyses of 40Ca(p→,p→) and 12C(p,n) at Ep = 500 MeV are reported. (orig.)
Magnetic dipole moments of the heavy tensor mesons in QCD
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.)
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.
Neutrinos with Magnetic Moment Depolarization Rate in Plasma
Elmfors, P; Raffelt, G G; Sigl, G; Elmfors, Per; Enqvist, Kari; Raffelt, Georg
1997-01-01
Neutrinos with a magnetic moment $\\mu$ change their helicity when interacting with an electromagnetic field. Various aspects of this effect have been described as spin precession, spin-flip scattering, and magnetic Cherenkov radiation. These perspectives are unified in an expression for the electromagnetic field distribution. Our general formula corrects a previous result and generalizes it to the case where the fields cannot be viewed as classical and where the momentum transfers need not be small. We evaluate our result explicitly for a relativistic QED plasma and determine the depolarization rate to leading order in the fine structure constant. Assuming that big-bang nucleosynthesis constraints do not allow a right-handed neutrino in equilibrium we derive the limit $\\mu<6.2\\EE{-11}\\mu_B$ on the neutrino magnetic moment. Bounds on $\\mu$ from a possible large scale magnetic fields are found to be more stringent even for very weak fields.
One-Particle Measurement of the Antiproton Magnetic Moment
DiSciacca, J; Marable, K; Gabrielse, G; Ettenauer, S; Tardiff, E; Kalra, R; Fitzakerley, D W; George, M C; Hessels, E A; Storry, C H; Weel, M; Grzonka, D; Oelert, W; Sefzick, T
2013-01-01
The antiproton $(\\bar{p})$ magnetic moment $\\mu \\bar{p} = \\mu_{\\bar{p}} S/(\\bar{h}/2)$ is proportional to its spin $S$. A single trapped $\\bar{p}$ is used for the first time to measure the $\\bar{p}$ magnetic moment in nuclear magnetons, giving $\\mu_\\bar{p}/\\mu N = -2.792 845 \\pm 0.000 012$. The 4.4 parts per million (ppm) uncertainty is 680 times smaller than previously realized. Comparing to the proton moment $\\mu_{p} = \\mu_{p} S/\\bar{h}/2)$ measured using the same method and trap electrodes gives $\\mu_{\\bar{p}}/\\mu_{p} = -1.000 000 \\pm 0.000 005$ to 5 ppm, consistent with the prediction of the CPT theorem.
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
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.
Semiclassical description of anomalous magnetic moment and chiral anomaly
It is shown that the same term of a modified Bargmann-Michel-Telegdi equation which explains the first-order radiative correction to the electronic magnetic moment accounts for the helicity variation in the infinite momentum limit. (author). 6 refs
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.
Composite scalar contributions to the anomalous magnetic moments
It is shown that the composite scalars recently introduced to explain the high Z0 → e+e-γ rate contribute too much to the lepton anomalous magnetic moments, unless one uses very accurate chiral symmetry or composite models with two preonic scales. (Author)
Supersymmetric magnetic moments sum rules and spontaneous supersymmetry breaking
In supersymmetry the anomalous magnetic moment of particles belonging to the same supermultiplet is related by simple sum rules. We study the modification of these sum rules in the case of the spontaneously broken N=1 global supersymmetry. (author). 9 refs, 3 figs
Neutrino emission in neutron matter from magnetic moment interactions
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
Electromagnetic soliton-particle with spin and magnetic moment
Chernitskii, Alexander A.
2012-01-01
Electromagnetic soliton-particle with both quasi-static and quick-oscillating wave parts is considered. Its mass, spin, charge, and magnetic moment appear naturally when the interaction with distant solitons is considered. The substantiation of Dirac equation for the wave part of the interacting soliton-particle is given.
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
Six-quark bag, exchange currents and trinucleon magnetic moments
The magnetic moments of 3H and 3He are reexamined in the Karl-Miller-Rafelski model of six-quark bag formation. Realistic three-nucleon wavefunctions are taken, and long-range one-pion exchange current corrections are included. It is concluded that the model is compatible with the data. (orig.)
Antineutrino Oscillations in the Atmospheric Sector
Himmel, Alexander I. [California Inst. of Technology (CalTech), Pasadena, CA (United States)
2011-05-01
This thesis presents measurements of the oscillations of muon antineutrinos in the atmospheric sector, where world knowledge of antineutrino oscillations lags well behind the knowledge of neutrinos, as well as a search for v_{μ} → $\\bar{v}$_{μ} transitions. Differences between neutrino and antineutrino oscillations could be a sign of physics beyond the Standard Model, including non-standard matter interactions or the violation of CPT symmetry. These measurements leverage the sign-selecting capabilities of the magnetized steel-scintillator MINOS detectors to analyze antineutrinos from the NuMI beam, both when it is in neutrino-mode and when it is in antineutrino-mode. Antineutrino oscillations are observed at |Δ$\\bar{m}$_{atm} ^{2}| = (3.36_{-0.40}^{+0.46}(stat) ± 0.06(syst)) x 10^{-3} eV^{2} and sin^{2}(2$\\bar{θ}$_{23}) = 0.860_{-0.12}^{+0.11}(stat) ± 0.01(syst). The oscillation parameters measured for antineutrinos and those measured by MINOS for neutrinos differ by a large enough margin that the chance of obtaining two values as discrepant as those observed is only 2%, assuming the two measurements arise from the same underlying mechanism, with the same parameter values. No evidence is seen for neutrino-to-antineutrino transitions.
Antineutrino Oscillations in the Atmospheric Sector
Himmel, Alexander I.; /Caltech
2011-05-01
This thesis presents measurements of the oscillations of muon antineutrinos in the atmospheric sector, where world knowledge of antineutrino oscillations lags well behind the knowledge of neutrinos, as well as a search for {nu}{sub {mu}} {yields} {bar {nu}}{sub {mu}} transitions. Differences between neutrino and antineutrino oscillations could be a sign of physics beyond the Standard Model, including non-standard matter interactions or the violation of CPT symmetry. These measurements leverage the sign-selecting capabilities of the magnetized steel-scintillator MINOS detectors to analyze antineutrinos from the NuMI beam, both when it is in neutrino-mode and when it is in antineutrino-mode. Antineutrino oscillations are observed at |{Delta}{bar m}{sub atm}{sup 2}| = (3.36{sub -0.40}{sup +0.46}(stat) {+-} 0.06(syst)) x 10{sup -3} eV{sup 2} and sin{sup 2}(2{bar {theta}}{sub 23}) = 0.860{sub -0.12}{sup +0.11}(stat) {+-} 0.01(syst). The oscillation parameters measured for antineutrinos and those measured by MINOS for neutrinos differ by a large enough margin that the chance of obtaining two values as discrepant as those observed is only 2%, assuming the two measurements arise from the same underlying mechanism, with the same parameter values. No evidence is seen for neutrino-to-antineutrino transitions.
In this document, I use some results of my research activities of the last ten years to show the power of x-ray magnetic dichroism for determining magnetic properties of thin layers, multilayers and nano-structures. The use of sum rules for x-ray dichroism allows a quantitative determination of the spin and orbital contributions to the magnetic moment, for each element of a heterogeneous material separately. Used in a qualitative way, x-ray dichroism allows monitoring the magnetization of the different layers in a multilayer material as a function of applied field. In combination with the temporal structure of synchrotron radiation, it is possible to study fast magnetization reversal with element selectivity, which is important for devices like spin valves and magnetic tunnel junctions. Adding the spatial resolution of a photoelectron emission microscope (PEEM), it becomes possible to study all the details of the fast magnetization reversal in complex magnetic systems. (author)
Gate-dependent orbital magnetic moments in carbon nanotubes
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....
A search of neutrino magnetic moments was carried out at the Kuo-Sheng nuclear power station at a distance of 28 m from the 2.9 GW reactor core. With a high purity germanium detector of mass 1.06 kg surrounded by scintillating NaI(Tl) and CsI(Tl) crystals as anti-Compton detectors, a detection threshold of 5 keV and a background level of 1 kg-1 keV-1 day-1 near threshold were achieved. Details of the reactor neutrino source, experimental hardware, background understanding, and analysis methods are presented. Based on 570.7 and 127.8 days of Reactor ON and OFF data, respectively, at an average Reactor ON electron antineutrino flux of 6.4x1012 cm-2 s-1, the limit on the neutrino magnetic moments of μνe-11μB at 90% confidence level was derived. Indirect bounds on the νe radiative decay lifetimes were inferred
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.
Magnetic moment of delta baryons with extended sea
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
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...
Nuclear magnetic and electric dipole moments of neon-19
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 ...
Magnetic moments of mirror nuclei with tilted-foil polarization
Lindroos, M; Broude, C; Goldring, G; Haas, H; Hass, M; Muellere, L; Pearson, M R; Weissman, L
2000-01-01
We report here on an ongoing experimental program initiated at the ISOLDE facility at CERN for the measurement of magnetic moments of short-lived radionuclides, with the emphasis on magnetic moments of mirror nuclei in far-from-stability regions. The nuclei are polarized by the tilted foil technique and the resulting 0-180 degrees beta asymmetry is monitored as a function of RF frequency applied in an NMR setup. In order to achieve sufficiently high energy for transmission through the foils, the experimental setup is mounted on a high voltage platform. The first experiment in this program was the measurement of the beta asymmetry and the NMR resonance for the ground state of /sup 23/Mg (I=3/2, T/sub 1/2 /=11 3 S), yielding mu =-0.533(6) nm. Improvements to the experimental setup are presently being designed, to be used in conjunction with the new developments at ISOLDE for obtaining high charge-state ions from the EBIS (REX- ISOLDE) ion source. This will help pave the way for measurements of magnetic moments ...
Magnetic moments and non-Fermi-liquid behavior in quasicrystals
Andrade, Eric
Motivated by the intrinsic non-Fermi-liquid behavior observed in the heavy-fermion quasicrystal Au51Al34Yb15, we study the low-temperature behavior of dilute magnetic impurities placed in metallic quasicrystals. We find that a large fraction of the magnetic moments are not quenched down to very low temperatures, leading to a power-law distribution of Kondo temperatures, accompanied by a non-Fermi-liquid behavior, in a remarkable similarity to the Kondo-disorder scenario found in disordered heavy-fermion metals. This work was supported by FAPESP (Brazil) Grant No. 2013/00681-8.
Nuclear magnetic moments measured by nuclear magnetic resonance on oriented nuclei
The configurations of nuclei near the shell closures N=40 and Z=40 were studied. The nuclear magnetic moments have been measured by nuclear magnetic resonance on oriented nuclei (NMR/ON). We have determined the ground state spin of 73Se and magnetic moments of isotopes 73Se(9/2+), 77Br3/2-) and 74Brm(4). The 9/2+ spin and parity assignment to the parent state of 73Se is perfectly compatible with the systematics of N + 39 and N = 41 isotones. The bromine moments around the shell closure N = 40, show a change in protonic configuration. In the second part of this work a precise hyperfine field value of zinc in iron has been determined. The relaxation constant of Zn in iron is established. The new hyperfine field value of zinc in iron allows a more precise reevaluation of the magnetic moments of 69Znm and 71Znm measured with NMR/ON
The secular variation of pulsar magnetic dipole moments
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.)
Calculated magnetic moments of Nd2Fe14B
Nordström, Lars; Johansson, Börje; Brooks, M. S. S.
1991-04-01
A self-consistent spin-polarized band-structure calculation has been performed for the technically important permanent magnet compound Nd2Fe14B. In contrast to earlier calculations, the localized 4f states on the Nd sites are treated in a consistent way. They are not allowed to contribute to the bonding, but they produce a local exchange field, felt by the valence electrons, which is calculated from first-principles local density theory. Assuming a Russel-Saunders coupled Nd 4f moment of 3.3μB/atom, the total magnetic moment is calculated to be 38.1μB/formula unit, to be compared with the experimental value 37.1μB/formula unit [Givord, Li, and Perrier de la Bathie, Solid State Commun. 51, 857 (1984)]. The calculated local Fe moments are quite different on the different crystallographic sites, varying from 2.1μB to 2.9μB/atom.
Calculated magnetic moments of Nd2Fe14B
A self-consistent spin-polarized band-structure calculation has been performed for the technically important permanent magnet compound Nd2Fe14B. In contrast to earlier calculations, the localized 4f states on the Nd sites are treated in a consistent way. They are not allowed to contribute to the bonding, but they produce a local exchange field, felt by the valence electrons, which is calculated from first-principles local density theory. Assuming a Russel--Saunders coupled Nd 4f moment of 3.3μB/atom, the total magnetic moment is calculated to be 38.1μB/formula unit, to be compared with the experimental value 37.1μB/formula unit [Givord, Li, and Perrier de la Bathie, Solid State Commun. 51, 857 (1984)]. The calculated local Fe moments are quite different on the different crystallographic sites, varying from 2.1μB to 2.9μB/atom
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
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
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)
Atomic ionization of germanium due to neutrino magnetic moments
Chen, Jiunn-Wei; Huang, Keh-Ning; Liu, C -P; Shiao, Hao-Tse; Singh, Lakhwinder; Wong, Henry T; Wu, Chih-Liang; Wu, Chih-Pan
2013-01-01
An ab initio calculation of atomic ionization of germanium (Ge) by neutrinos was carried out in the framework of multiconfiguration relativistic random phase approximation. The main goal is to provide a more accurate cross section formula than the conventional one, which is based on the free electron approximation, for searches of neutrino magnetic moments with Ge detectors whose threshold is reaching down to the sub-keV regime. Limits derived with both methods are compared, using reactor neutrino data taken with low threshold germanium detectors.
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.
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...
Quark Mass Dependence of Nucleon Magnetic Moment and Charge Radii
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.
Symmetry-related motional enhancement of exciton magnetic moment
Tronc, P. [Laboratoire d' Optique, Ecole Superieure de Physique et Chimie Industrielles, Paris (France)
2010-05-15
A dramatic motional enhancement of heavy- and light-hole exciton magnetic moment in zinc-blende semiconductors under a magnetic field applied parallel to the [001] direction has been put into evidence when the exciton moves along the same direction [J. J. Davies et al., Phys. Rev. Lett. 97, 187403 (2006)]. The authors of the paper assigned the effect to a mixing between the 1S and 2P exciton states arising from the cubic term in the Luttinger Hamiltonian expansion in momentum. Such exciton states do not take into account the exact crystal structure since they are just eigenstates of the angular momentum. In addition, the Luttinger Hamiltonian does not take into account the full magnetic-field effect since it does not include the gauge transformations under the symmetry operations of the structure under the field. By determining the exact symmetry of the exciton states, it is shown here that, under a field parallel to the [001] direction, the Zeeman Splitting value vanishes at the {gamma} point and, due to accidental quasi-degeneracy in energy between dark and bright exciton states, becomes finite when the exciton moves parallel to the field. A perturbation model allows fitting experimental data and explains the exciton magnetic-moment enhancement with kinetic energy. On the contrary, under a field parallel to the [110] direction with the exciton moving parallel to the field, no accidental degeneracy probably takes place between exciton states. As a consequence, the concept of Zeeman Splitting is not relevant since no energy level is degenerate. In addition, a possible quasi-degeneracy between the excitons recombining with the {sigma}{sup +} and {sigma}{sup -} polarizations, respectively, would not allow coupling their two states, hence would not change notably the experimental results. (Abstract Copyright [2010], Wiley Periodicals, Inc.)
Magnetic Moment Fields in Dense Relativistic Plasma Interacting with Laser Radiations
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
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...
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...
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
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.
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
On the origin of the giant magnetic moment of the Al-Mn quasicrystals
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.
Magnetic moments and hyperfine fields at Fe in 3d-transition metals
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.)
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.
Charged point particles with magnetic moment in general relativity
Halbwachs Lagrangean formalism for the theory of charged point particles with spin (g = 2) is generalized and formulated in General Relativity for particles of arbitrary charge and magnetic moment. Equations are obtained, both corresponding to Frenkel's condition Ssub(μν)Xsup(ν) = 0 and to Nakano's condition Ssub(μν)Psup(ν) = 0. With the later condition the exact equations are highly coupled and non linear. When linearized in the electromagnetic and gravitational fields they coincide with de Groot-Suttorp equations for vanishing gravitational fields and with Dixon-Wald equations in the absence of electromagnetic field. The equations corresponding to Frenkel's condition, when linearized in Ssub(μν), coincide with Papapetrou's and Frenkel's equations in the corresponding limits
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
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)
We report on a strong perpendicular magnetic anisotropy in [CoFe 0.4 nm/Pd t]6 (t=1.0–2.0 nm) multilayers fabricated by DC sputtering in an ultrahigh vacuum chamber. Saturation magnetization, Ms, and uniaxial anisotropy, Ku, of the multilayers decrease with increasing the spacing thickness; with a Ms of 155 emu/cc and a Ku of 1.14×105 J/m3 at a spacing thickness of t=2 nm. X-ray absorption spectroscopy and X-ray magnetic circular dichroism measurements reveal that spin and orbital magnetic moments of Co and Fe in CoFe film decrease as a function of Pd thickness, indicating the major contribution of surface/interfacial magnetism to the magnetic properties of the film. - Highlights: • Strong perpendicular magnetic anisotropy essentially contributed by interfacial anisotropy. • Controllably magnetic properties with low Ms, high Ku, high P. • Interfacial magnetic moments modified by CoFe/Pd interfaces with strong spin–orbit coupling. • Narrow Bloch walls with Néel caps. • Superior magnetic characteristics for spin-torque applications
Magnetic-Compton-scattering study of spin moments in UFe2
Spin moments were derived from the magnetic-Compton profile of UFe2, which was measured using 59.38-keV circularly polarized synchrotron radiation from the Accumulation Ring Source at KEK, Japan. Although the net moment on the uranium site is no more than a tenth of a Bohr magneton, the individual spin and orbital moments, which are coupled antiparallel, are much larger and it is the spin moment that can be determined in magnetic-Compton scattering. The data have been analyzed in terms of the U 5f, Fe 3d and delocalized spin moments. The observed uranium-5f spin moment is less than half (i.e., B) and the diffuse spin moment more than double (i.e., >0.20μB) those predicted from theory. These values compare favorably with those deduced from neutron measurements of the total magnetization. copyright 1997 The American Physical Society
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.
Progress in analytical calculations for the anomalous magnetic moment of the muon
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.
Anomalous-Magnetic-Moment Effects in a Strongly Magnetized and Dense Medium
Ferrer, E J; Paret, D Manreza; Martínez, A Pérez
2013-01-01
We investigate the quantum corrections of the anomalous magnetic moment (AMM) for fermions in the presence of a strong magnetic field using the Ritus's approach. At strong fields the particles get different AMM's depending on the LL's. This result is different from what is obtained with the Schwinger's approximation at weak field where the AMM is independent of the LL. We analyze the significance of the AMM contribution to the Equation of State (EoS) of the magnetized system, in the weak and strong field approximations.
Measurement of the magnetic moment of the negative muon bound in different atoms
Theoretical calculations show that the magnetic moment of the electron and the negative muon in the bound state in an atom should be different from the magnetic moment of the free particle due to their relativistic motion. There are also additional radiative corrections to the magnetic moment of a bound electron (muon) due to the presence of the strong Coulomb field of the atomic nucleus. The results of the measurements of the magnetic moment of the negative muon in carbon, oxygen, magnesium, silicon, sulfur, and zinc are presented. The accuracy of the measurements makes it possible to prove the dependence of the relativistic correction to the magnetic moment of a bound muon on Z of the atom
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.
Supernova Relic Electron Neutrinos and anti-Neutrinos in future Large-scale Observatories
Volpe, C
2007-01-01
We investigate the signal from supernova relic neutrinos in future large scale observatories, such as MEMPHYS (UNO, Hyper-K), LENA and GLACIER, at present under study. We discuss that complementary information might be gained from the observation of supernova relic electron anti-neutrinos and neutrinos using the scattering on protons on one hand, and on nuclei such as oxygen, carbon or argon on the other hand. When determining the relic neutrino fluxes we also include, for the first time, the coupling of the neutrino magnetic moment to magnetic fields within the core-collapse supernova. We present numerical results on both the relic electron neutrino and anti-neutrino fluxes and on the number of events for electron neutrinos on carbon, oxygen and argon, as well as electron anti-neutrinos on protons, for various oscillation scenarios. The observation of supernova relic neutrinos might provide us with unique information on core-collapse supernova explosions, on the star formation history and on neutrino propert...
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...
Evaluation of orbital moment in Ni-Zn ferrites: A magnetic Compton scattering study
Temperature dependent magnetic Compton profiles of Ni1-xZnxFe2O4 (x = 0.0, 0.1, 0.2) ferrites have been decomposed into component profiles to determine the site-specific magnetic moments. For a quantitative evaluation of orbital moment, the spin momentum density data have been combined with magnetization data. Interestingly, the orbital magnetic moment decreases from 0.25 ± 0.03 μB/f.u. (for x = 0.0) to 0.09 ± 0.03 μB/f.u. (for x = 0.2) which is in contrast to spin moment. A decrease in ratio of orbital to spin moments in Ni rich ferrites is explained on the basis of spin-orbit coupling and crystal field interaction.
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...
Field Induced Magnetic Moments in a Metastable Iron-Mercury Alloy
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...... moment for the iron-mercury alloy extrapolated to 0 K was found to be 2.40 Bohr magnetons per iron atom. By applying magnetic fields up to 12 T it was possible to further increase the magnetization. Mossbauer results showed that the high field susceptibility could not be explained by spin canting effects...
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 ...
Enhanced magnetic moment of ultrathin Co films measured by in situ electrodeposition in a SQUID
Topolovec, Stefan; Krenn, Heinz; Würschum, Roland
2016-01-01
A special electrochemical cell enabling in situ electrodeposition in a SQUID magnetometer is applied to study the magnetic moment of ultrathin Co films during growth on an Au(111) substrate. The in situ electrodeposition approach allows a total elimination of the magnetic background signal of the substrate, thus the magnetic moment which arises exclusively from the deposited Co film could be measured with monolayer sensitivity. The average thickness of the deposited Co films dav as determined from the transferred charge can be adjusted easily by varying the parameters of the electrodeposition. Hence, the magnetic moment of Co thin films could be determined in absolute terms as a function of the film thickness dav. For the first few atomic layers an enhancement of the magnetic moment per Co atom compared to the bulk could be observed, which increases steadily with lowering dav, reaching up to 40%.
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.
2015-08-01
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-shift cantilever magnetometry. We find that the magnetic moment of the rod is μ = 1.1 ± 0.1 × 10-12 Am2, 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.
Enhancement of Fe Magnetic Moments in Fe/Co (001 Multilayers
Marienette Morales
2004-12-01
Full Text Available In order to investigate the electronic and magnetic properties of a bcc Fe/Co (001 multilayer, we have performed electronic structure calculations employing the total energy full-potential linear muffin tin orbital method. The magnetic moments of the layers are calculated. Based on these results, the magnetization profiles and the microscopic origin of the enhancement of Fe moments in the multilayers of the same Co content but with different interface qualities are reported. Large enhancement of magnetic moment is observed in the Fe monolayer located at the interface, and an even greater increase is obtained for the multilayer with one monolayer of intermixing between Fe and Co layers. The Co atoms were found to have similar magnetic moments in the bulk and at the interface.
Antiproton magnetic moment determined from the HFS of p-bar He+
We report a determination of the antiproton magnetic moment, measured in a three-body system, independent of previous experiments. We present results from a systematic study of the hyperfine (HF) structure of antiprotonic helium where we have achieved a precision more than a factor of 10 better than our first measurement. A comparison between the experimental results and three-body quantum electrodynamic (QED) calculations leads to a new value for the antiproton magnetic moment μsp-bar=-2.7862(83)μN, which agrees with the magnetic moment of the proton within 2.9x10-3.
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.
Hypernuclear Magnetic Moments and ∧-N Interaction in 17∧O
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.
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.
Field Induced Magnetic Moments in a Metastable Iron-Mercury Alloy
Pedersen, M.S.; Mørup, Steen; Linderoth, Søren; Johansson, C.; Hanson, M.
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...... moment for the iron-mercury alloy extrapolated to 0 K was found to be 2.40 Bohr magnetons per iron atom. By applying magnetic fields up to 12 T it was possible to further increase the magnetization. Mossbauer results showed that the high field susceptibility could not be explained by spin canting effects....... 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....
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...
Quantized magnetic moment at the edge of a single-walled carbon nanotube
Jeng, Horng-Tay; Oshikawa, Masaki; Lin, Hsiu-Hau
2010-01-01
We investigate many-body effects near the edge of a single-walled carbon nanotube and find it turns magnetic with quantized edge moment solely depends on the chiral vector, i.e. the topology of the carbon nanotube. The distribution of the edge moment reveals an approximate supersymmetry even in a realistic model. Our findings demonstrate crucial importance of the interplay between the electronic correlation and the edge morphology. The edge moment provides an excellent candidate for nanomagne...
Cancellation of spin and orbital magnetic moments in δ-Pu: Theory
Density functional theory (DFT), in conjunction with the fixed-spin-moment (FSM) method, spin-orbit coupling (SO), and orbital polarization (OP), is shown to retain key features of the conventional DFT treatment of δ-Pu while at the same time not producing the substantial net magnetic moments commonly predicted by this theory. It is shown that when a small adjustment of the spin moment (less than 20%) is allowed, a complete spin- and orbital-moment cancellation occurs which results in a zero net magnetic moment in δ-Pu. This minor modification, accomplished by the FSM method, is shown to have a very small effect on the calculated total energy as well as the electron density-of-states (DOS). The photoemission spectra (PES), obtained from the DOS of the present model, compares equal or better to measured spectra, than that of two other recent non-magnetic models for δ-Pu
X-ray detection of transient magnetic moments induced by a spin current in Cu
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.
X-ray Detection of Transient Magnetic Moments Induced by a Spin Current in Cu
Kukreja, R.; Bonetti, S.; Chen, Z.; Backes, D.; Acremann, Y.; Katine, J. A.; Kent, A. D.; Dürr, H. A.; Ohldag, H.; Stöhr, J.
2015-08-01
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 ×10-5μB 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 ×10-3μB per atom. This reveals the dominance of spin-torque alignment over Joule heat induced disorder of the interfacial Cu moments during current flow.
Quantum tunneling of the magnetic moment in the S/F/S Josephson φ0 junction
Chudnovsky, Eugene M.
2016-04-01
We show that the S/F/S Josephson φ0 junction permits detection of macroscopic quantum tunneling and quantum oscillation of the magnetic moment by measuring the ac voltage across the junction. Exact expression for the tunnel splitting renormalized by the interaction with the superconducting order parameter is obtained. It is demonstrated that magnetic tunneling may become frozen at a sufficiently large φ0. The quality factor of quantum oscillations of the magnetic moment due to finite ohmic resistance of the junction is computed. It is shown that magnetic tunneling rate in the φ0 junction can be controlled by the bias current, with no need for the magnetic field.
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.
Spins and magnetic moments of rubidium and cesium nuclides far from stability
Previous studies at ISOLDE have concerned spins and magnetic moments of neutron-deficient rubidium and cesium isotopes. Here, the main results obtained, and, in the case of cesium, new moment measurements are briefly discussed also the results from measurements on neutron-rich nuclides of rubidium and cesium. (orig./AH)
A study of magnetic moments of CeRh3B2 by X-ray magnetic diffraction experiments
X-ray magnetic diffraction experiments of a ferromagnetic rare-earth compound CeRh3B2 have been performed, and the spin and orbital magnetic form factors have been measured. Density distributions of the spin and orbital magnetic moments in real space have been obtained by using Maximum Entropy Method. Low peaks at Rh sites as well as high peaks at Ce sites are observed in these distribution maps. We have estimated the spin and orbital magnetic moments at the Ce and Rh sites in the distribution maps, and have obtained small but nonnegligible spin and orbital magnetic moments of Rh. This is probably the first experimental evidence showing existence of the spin and orbital moments of Rh in this compound.
Planar Hall ring sensor for ultra-low magnetic moment sensing
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...
Antineutrino Monitoring of Thorium Reactors
Akindele, Oluwatomi A; Norman, Eric B
2015-01-01
Various groups have demonstrated that antineutrino monitoring can be successful in assessing the plutonium content in water-cooled nuclear reactors for nonproliferation applications. New reactor designs and concepts incorporate nontraditional fuels types and chemistry. Understanding how these properties affect the antineutrino emission from a reactor can extend the applicability of antineutrino monitoring.Thorium molten salt reactors (MSR) breed U-233, that if diverted constitute an IAEA direct use material. The antineutrino spectrum from the fission of U-233 has been determined, the feasibility of detecting the diversion of a significant quantity, 8 kg of U-233, within the IAEA timeliness goal of 30 days has been evaluated. The antineutrino emission from a thorium reactor operating under normal conditions is compared to a diversion scenario at a 25 meter standoff by evaluating the daily antineutrino count rate and the energy spectrum of the detected antineutrinos. It was found that the diversion of a signifi...
Core Polarization and Tensor Coupling Effects on Magnetic Moments of Hypernuclei
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.
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.
Perihelion Precession in Gravitational Field of Center Mass with Electric Charge and Magnetic Moment
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.
An approach that can be used to measure the magnetic moment of a magnetized nanoparticle or nanostructure from an electron-optical phase image is introduced. The measurement scheme is based on integration of the gradient of the measured phase image within a circular boundary that contains the structure of interest. The quantity obtained is found to be directly proportional to the magnetic moment of the particle, with a constant of proportionality that does not depend on the particle's shape or magnetization state. The measurement of magnetic moments from both simulated and experimental phase images is demonstrated, and strategies are presented that can be utilized to overcome sources of error associated with, for example, the presence of neighboring magnetic particles and the perturbation of the holographic reference wave.
Beleggia, Marco; Kasama, Takeshi; Dunin-Borkowski, Rafal E.
2010-01-01
An approach that can be used to measure the magnetic moment of a magnetized nanoparticle or nanostructure from an electron-optical phase image is introduced. The measurement scheme is based on integration of the gradient of the measured phase image within a circular boundary that contains the...... structure of interest. The quantity obtained is found to be directly proportional to the magnetic moment of the particle, with a constant of proportionality that does not depend on the particle's shape or magnetization state. The measurement of magnetic moments from both simulated and experimental phase...... images is demonstrated, and strategies are presented that can be utilized to overcome sources of error associated with, for example, the presence of neighboring magnetic particles and the perturbation of the holographic reference wave...
Ionization of hydrogen by neutrino magnetic moment, relativistic muon, and WIMP
Chen, Jiunn-Wei; Liu, C.-P.(Department of Physics, National Dong Hwa University, Shoufeng, Hualien 97401, Taiwan); Liu, Chien-Fu; Wu, Chih-Liang
2013-01-01
We studied the ionization of hydrogen by scattering of neutrino magnetic moment, relativistic muon, and weakly-interacting massive particle with a QED-like interaction. Analytic results were obtained and compared with several approximation schemes often used in atomic physics. As current searches for neutrino magnetic moment and dark matter have lowered the detector threshold down to the sub-keV regime, we tried to deduce from this simple case study the influence of atomic structure on the th...
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...
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.
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...
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.
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.
Light-by-light scattering and muon's anomalous magnetic moment
implications of these results for mesons in both the light-quark sector and the charm-quark sector. In the second part of this thesis we develop the formalism to provide an improved estimate for the hadronic light-by-light (HLbL) correction to the muon's anomalous magnetic moment aμ, by considering single meson contributions beyond the leading pseudo-scalar mesons. This is motivated by the present 3σ deviation between the measurement of aμ and its estimate in the Standard Model. Furthermore, a forthcoming new experiment at Fermilab aims to improve the experimental precision by a factor of 4 which also requires a similar theoretical improvement. We incorporate available experimental input as well as constraints from light-by-light scattering sum rules to estimate the effects of axial-vector, scalar, and tensor mesons. We give numerical evaluations for the HLbL contribution of these states to aμ. The presented formalism allows to further improve on these estimates, once new data for such meson states will become available. In the last part of this work, we present a new dispersion formalism developed for the HLbL contribution to aμ and test the formalism for the case of scalar field theory. The new framework opens a unique possibility for a consistent incorporation of data from e+e- colliders for single- as well as multi-meson contributions. Furthermore, it allows to systematically control the HLbL uncertainty in the aμ which is a crucial step in searches of new physics using this precision quantity.
Two dimensional electron gas confined over a spherical surface: Magnetic moment
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.
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.
Magnetization, magnetic susceptibility, effective magnetic moment of Fe3+ ions in Bi25FeO39 ferrite
Magnetic susceptibility for ferrite Bi25FeO39 is measured at 5–950 K in the magnetic field of 0.86 T. It is shown that Bi25FeO39 is paramagnetic in the temperature range 5−950 K. The saturation magnetization is equal to 5.04μB per formula unit at 5 K in a magnetic field of 10 T. It is found that at 5−300 K the effective magnetic moment of Fe3+ ions in Bi25FeO39 is equal to 5.82μB. - Graphical abstract: The dependence of the magnetization (n, μB) on the magnetic field for one formula unit of Bi25FeO39 at 5 K. - Highlights: • Magnetic susceptibility for Bi25FeO39 is measured at 5–950 K in the magnetic field of 0.86 T. • It is shown that Bi25FeO39 is paramagnetic in the temperature range 5−950 K. • The saturation magnetization is equal to 5.04μB per formula unit at 5 K in a magnetic field of 10 T
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.
A prototype vector magnetic field monitoring system for a neutron electric dipole moment experiment
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
The net magnetic moment of an assemblage of randomly oriented dipoles
Kristjansson, L.
2011-01-01
The expected distribution of net magnetic moments, as measured for a randomized assemblage of magnetic dipoles whose magnitudes have a lognormal distribution, is derived. The results are compared with experiments on rock chips.DOI: 10.1111/j.2153-3490.1973.tb00614.x
Orbital magnetic moment in Ir doped CaMnO3
The magnetism of CaMn0.55Ir0.45O3 has been studied using the magnetic Compton scattering technique. The analysis of the magnetic Compton profile shows that the spin moments of Mn and Ir form an antiparallel configuration, establishing ferrimagnetism. Moreover, the experimental results indicate the existence of an orbital moment 0.2 μB/f.u.. The possible model for these results has been discussed under the framework of the localized electron model by taking account of the electronic states of the Ir4+ ion.
Appreciable magnetic moment and energy density in single step normal route synthesized MnBi
Christopher, Nithya R.; Singh, Nidhi; Singh, Shiva Kumar; Gahtori, Bhasker; Mishra, S. K.; Dhar, A.; Awana, V. P. S.
2013-01-01
We study the structural and magnetic properties of the MnBi inter-metallic compound. The LTP (Low Temperature Phase) MnBi compound is successfully synthesized in single step by vacuum encapsulation technique and rapid quenching from phase formation temperature. The phase purity and the magnetic moments of MnBi are highly dependent on heat treating schedule. The best phase purity and the magnetic moment are found for a sample heat treated at 310oC for 48h. Rietveld fitted X-ray diffraction (XR...
Quantum aspects of a moving magnetic quadrupole moment interacting with an electric field
The quantum dynamics of a moving particle with a magnetic quadrupole moment that interacts with electric and magnetic fields is introduced. By dealing with the interaction between an electric field and the magnetic quadrupole moment, it is shown that an analogue of the Coulomb potential can be generated and bound state solutions can be obtained. Besides, the influence of the Coulomb-type potential on the harmonic oscillator is investigated, where bound state solutions to both repulsive and attractive Coulomb-type potentials are achieved and the arising of a quantum effect characterized by the dependence of the harmonic oscillator frequency on the quantum numbers of the system is discussed
Pinning and switching of magnetic moments in bilayer graphene
Castro, Eduardo V; Lopez-Sancho, M P; Vozmediano, M A H [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain)], E-mail: evcastro@icmm.csic.es, E-mail: pilar@icmm.csic.es, E-mail: vozmediano@icmm.csic.es
2009-09-15
We examine the magnetic properties of the localized states induced by lattice vacancies in bilayer graphene with an unrestricted Hartree-Fock calculation. We show that, with realistic values of the parameters and for experimentally accessible gate voltages, we can have magnetic switching between an unpolarized and a fully polarized system.
Pinning and switching of magnetic moments in bilayer graphene
We examine the magnetic properties of the localized states induced by lattice vacancies in bilayer graphene with an unrestricted Hartree-Fock calculation. We show that, with realistic values of the parameters and for experimentally accessible gate voltages, we can have magnetic switching between an unpolarized and a fully polarized system.
Gamma-ray halos as a measure of intergalactic magnetic fields: a classical moment problem
Ahlers, Markus
2011-01-01
The presence of weak intergalactic magnetic fields can be studied by their effect on electro-magnetic cascades induced by multi-TeV gamma-rays in the cosmic radiation background. Small deflections of secondary electrons and positrons as the cascade develops extend the apparent size of the emission region of distant TeV gamma-ray sources. These gamma-ray halos can be resolvable in imaging atmospheric Cherenkov telescopes and serve as a measure of the intergalactic magnetic field strength and coherence length. We present a method of calculating the gamma-ray halo for isotropically emitting sources by treating magnetic deflections in the cascade as a diffusion process. With this ansatz the moments of the halo follow from a set of simple diffusion-cascade equations. The reconstruction of the angular distribution is then equivalent to a classical moment problem. We present a simple solution using Pade approximations of the moment's generating function.
Majorana neutrino magnetic moment and neutrino decoupling in big bang nucleosynthesis
Vassh, N.; Grohs, E.; Balantekin, A. B.; Fuller, G. M.
2015-12-01
We examine the physics of the early universe when Majorana neutrinos (νe, νμ, ντ) 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 abundances and other cosmological parameters are sensitive to magnetic couplings on the order of 1 0-10μB. Given the recent analysis of sub-MeV Borexino data which constrains Majorana moments to the order of 1 0-11μB or less, we find that changes in cosmological parameters from magnetic contributions to neutrino decoupling temperatures are below the level of upcoming precision observations.
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
Magnetic moments in chemically ordered mass-selected CoPt and FePt clusters
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 L10-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 L10-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
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.…
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.
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 moments of cascade baryons with strange sea in statistical model
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
Unusual temperature dependence of the magnetic moment in URu2Si2
The influence of the sample quality on the magnetic properties of the heavy-fermion superconductor URu2Si2 has been studied by elastic neutron scattering. Two single crystals prepared under identical conditions received different heat treatments. The as-grown crystal shows an unusual temperature dependence of the magnetic Bragg peak intensity. The annealed sample behaves normally. The low-temperature magnetic moment is identical for the two samples, showing that the small moment of 0.023 (3) μB is intrinsic. By varying the instrumental resolution, we show that the ordered moment as well as the limited correlation length (200-400 A) are of static origin. The finite correlation length appears related to defects. (author). 9 refs., 1 fig
Magnetic moment interactions in the e--e+ system
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.)
Forces on a current loop and magnetic moment
We compute the action of a static magnetic field on a current loop. From this we recover the definition of m as given in textbooks. The presentation is accessible to undergraduate students with a knowledge of the basic notions of classical electromagnetism. (letters and comments)
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...
Colossal magnetic moment in Cr and Er co-implanted GaN films
Gao, Xingguo [School of Science, Qilu University of Technology, Jinan 250353 (China); Liu, Chao, E-mail: cliu@semi.ac.cn [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Tao, Dongyan; Zeng, Yiping [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)
2015-09-25
Highlights: • The ions co-implantation induced some new Raman phonon modes. • All the samples were confirmed to be ferromagnetic at room temperature. • The colossal magnetic moment may be induced by the 3d–4f coupling. • Electrons are more effective than holes in facilitating the magnetic coupling. • Cr and Er ions play a complementary role in determining the magnetic anisotropy. - Abstract: Colossal magnetic moment up to 16.05 μ{sub B}/atom was found in GaN based diluted magnetic semiconductor films, which were fabricated by co-implantation with Cr and Er ions, followed by 800 °C annealing process. No secondary phase was detected in our samples within the detection limit of the high resolution X-ray diffractometer. Several new Raman peaks around 300, 360, 663 and 858 cm{sup −1} are observed in the implanted and annealed samples, which have been explained reasonably. The colossal magnetic moment may come from the 3d–4f coupling between Cr and Er ions and/or the interaction between bound magnetic polarons formed in our samples, which can be facilitated by higher electron concentration. Cr and Er ions play a complementary role in determining the magnetic anisotropy.
Ionization of hydrogen by neutrino magnetic moment, relativistic muon, and WIMP
Chen, Jiunn-Wei; Liu, Chien-Fu; Wu, Chih-Liang
2013-01-01
We studied the ionization of hydrogen by scattering of neutrino magnetic moment, relativistic muon, and weakly-interacting massive particle with a QED-like interaction. Analytic results were obtained and compared with several approximation schemes often used in atomic physics. As current searches for neutrino magnetic moment and dark matter have lowered the detector threshold down to the sub-keV regime, we tried to deduce from this simple case study the influence of atomic structure on the the cross sections and the applicabilities of various approximations. The general features being found will be useful for cases where practical detector atoms are considered.
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.
SNO results and neutrino magnetic moment solution to the solar neutrino problem
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.
The QED vacuum polarization function at four loops and the anomalous magnetic moment at five loops
The anomalous magnetic moment of the muon is one of the most fundamental observables. It has been measured experimentally with a very high precision and on theory side the contributions from perturbative QED have been calculated up to five-loop level by numerical methods. Contributions to the muon anomalous magnetic moment from certain diagram classes are also accessible by alternative methods. In this paper we present the evaluation of contributions to the QED corrections due to insertions of the vacuum polarization function at five-loop level
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.
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
Determination of magnetic-moment directions using x-ray resonant exchange scattering
We present determinations of the magnetic structures of NdNi2B2C and SmNi2B2C by means of x-ray resonant exchange scattering (XRES). The integrated intensity of a number of magnetic reflections was measured as a function of the Bragg angle and compared to model calculations for various magnetic structures. The two compounds were found to have the same magnetic modulation wave vector but different moment directions. A resonant feature observed below the Sm L3-absorption edge, similar to unexplained effects found in other light rare-earth compounds, is identified as quadrupolar XRES and is used to refine the details of the moment direction. copyright 1997 The American Physical Society
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.
Induced magnetic moment on Cu(1) in YBaCuOx compounds
The first investigation of a YBaCuO compound by polarised neutron diffraction (p.n.d.) on a YBa2Cu3O6.5 single crystal, has revealed the existence of a small magnetic moment on Cu(1). We report here on new p.n.d. results on a x = 6.4 single crystal. The magnetisation density demonstrates an induced magnetic moment on Cu(1), m = 0.02 μB slightly larger than for x = 6.5, in the same conditions of temperature and field (T = 1.7 K, H = 5 T). The temperature and field dependence of the induced moment are discussed in connection with a model of antiferromagnetically coupled spins on Cu(1)
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 multiquasiparticle 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.
Magnetic moments of vector, axial, and tensor mesons in lattice QCD
Lee, F X; Wilcox, W
2008-01-01
We present a calculation of magnetic moments for selected spin-1 mesons using the techniques of lattice QCD. This is carried out by introducing progressively small static magnetic field on the lattice and measuring the linear response of a hadron's mass shift. The calculations are done on $24^4$ quenched lattices using standard Wilson actions, with $\\beta$=6.0 and pion mass down to 500 MeV. The results are compared to those from the form factor method where available.
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.
Local magnetic moment and hyperfine field in hydrogenated iron and iron-vanadium alloy
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.)
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
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.
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...
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
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.