1,007 research outputs found

    Time-reversal violating generation of static magnetic and electric fields and a problem of electric dipole moment measurement

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    It is shown that in the experiments for search of the EDM of an electron (atom, molecule) the T-odd magnetic moment induced by an electric field and the T-odd electric dipole moment induced by a magnetic field will be also measured. It is discussed how to distinguish these contributions.Comment: Latex, 5 pages with 1 Postscript figur

    A multiloop improvement of non-singlet QCD evolution equations

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    An approach is elaborated for calculation of "all loop" contributions to the non-singlet evolution kernels from the diagrams with renormalon chain insertions. Closed expressions are obtained for sums of contributions to kernels P(z)P(z) for the DGLAP equation and V(x,y)V(x,y) for the "nonforward" ER-BL equation from these diagrams that dominate for a large value of b0b_0, the first β\beta-function coefficient. Calculations are performed in the covariant ξ\xi-gauge in a MS-like scheme. It is established that a special choice of the gauge parameter ξ=3\xi=-3 generalizes the standard "naive nonabelianization" approximation. The solutions are obtained to the ER-BL evolution equation (taken at the "all loop" improved kernel), which are in form similar to one-loop solutions. A consequence for QCD descriptions of hard processes and the benefits and incompleteness of the approach are briefly discussed.Comment: 13 pages, revtex, 2 figures are enclosed as eps-file, the text style and figures are corrected following version, accepted for publication to Phys. Rev.

    Description of paramagnetic--spin glass transition in Edwards-Anderson model in terms of critical dynamics

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    Possibility of description of the glass transition in terms of critical dynamics considering a hierarchy of the intermodal relaxation time is shown. The generalized Vogel-Fulcher law for the system relaxation time is derived in terms of this approach. It is shown that the system satisfies the fluctuating--dissipative theorem in case of the absence of the intermodal relaxation time hierarchy.Comment: 10 pages, 6 figure

    Effects of Turbulent Mixing on the Critical Behavior

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    Effects of strongly anisotropic turbulent mixing on the critical behavior are studied by means of the renormalization group. Two models are considered: the equilibrium model A, which describes purely relaxational dynamics of a nonconserved scalar order parameter, and the Gribov model, which describes the nonequilibrium phase transition between the absorbing and fluctuating states in a reaction-diffusion system. The velocity is modelled by the d-dimensional generalization of the random shear flow introduced by Avellaneda and Majda within the context of passive scalar advection. Existence of new nonequilibrium types of critical regimes (universality classes) is established.Comment: Talk given in the International Bogolyubov Conference "Problems of Theoretical and Mathematical Physics" (Moscow-Dubna, 21-27 August 2009

    High frequency dielectric and magnetic anomaly at the phase transition in NaV2O5

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    We found anomalies in the temperature dependence of the dielectric and the magnetic susceptibiliy of NaV_2O_5 in the microwave and far infrared frequency ranges. The anomalies occur at the phase transition temperature T_c, at which the spin gap opens. The real parts of the dielectric constants epsilon_a and epsilon_c decrease below T_c. The decrease of epsilon_a (except for the narrow region close to T_c) is proportional to the intensity of the x-ray reflection appearing at T_c. The dielectric constant anomaly can be explained by the zigzag charge ordering in the ab-plane appearing below T_c. The anomaly of the microwave magnetic losses is probably related to the coupling between the spin and charge degrees of freedom in vanadium ladders.Comment: 3 PS-figures, LATEX-text, new experimental data added, typos correcte

    A simple analytical model for dark matter halo structure and adiabatic contraction

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    A simple analytical model for describing inner parts of dark matter halo is considered. It is assumed that dark matter density is power-law. The model deals with dark matter distribution function in phase space of adiabatic invariants (radial action and angular momentum). Two variants are considered for the angular part of the distribution function: narrow and broad distribution. The model allows to describe explicitly the process of adiabatic contraction of halo due to change of gravitational potential caused by condensation of baryonic matter in the centre. The modification of dark matter density in the centre is calculated, and is it shown that the standard algorithm of adiabatic contraction calculation overestimates the compressed halo density, especially in the case of strong radial anisotropy.Comment: 5 pages, 3 figures. v3 - major improvements, another halo model introduced, discussion extende

    Study of the ρ\rho, ω\omega, ϕηγ7γ\phi\to\eta\gamma\to 7\gamma Decays with an SND Detector on a VEPP-2M Collider

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    The e+eηγ7γe^+e^-\to\eta\gamma\to 7\gamma process was studied in the energy range 2E=600÷10602E=600\div 1060 MeV with an SND detector on a VEPP-2M e+ee^+e^- collider. The decay branching ratios B(ϕηγ)=(1.343±0.012±0.055)102B(\phi\to\eta\gamma)=(1.343\pm 0.012\pm 0.055)\cdot 10^{-2}, B(ωηγ)=(4.60±0.72±0.19)104B(\omega\to\eta\gamma)=(4.60\pm 0.72\pm 0.19)\cdot 10^{-4}, and B(ρηγ)=(2.69±0.32±0.16)104B(\rho\to\eta\gamma)=(2.69\pm 0.32\pm 0.16)\cdot 10^{-4} were measured.Comment: 5 pages, 4 figure

    Magnetic Resonance of the Intrinsic Defects of the Spin-Peierls Magnet CuGeO3

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    ESR of the pure monocrystals of CuGeO3 is studied in the frequency range 9-75 GHz and in the temperature interval 1.2-25 K. The splitting of the ESR line into several spectral components is observed below 5 K, in the temperature range where the magnetic susceptibility is suppressed by the spin-Peierls dimerization. The analysis of the magnetic resonance signals allows one to separate the signals of the S=1/2- and S=1 defects of the spin-Peierls phase. The value of g-factor of these signals is close to that of the Cu-ion. The additional line of the magnetic resonance is characterized by an anomalous value of the g-factor and by the threshold-like increase of the microwave susceptibility when the microwave power is increasing. The ESR signals are supposingly attributed to two types of the planar magnetic defects, arising at the boundaries of the domains of the spin-Peierls state with the different values of the phase of the dimerization.Comment: LATEX-text, 12 PS-figures, typos corrected, LATEX-style change
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