5,282 research outputs found

    On Dimensional Degression in AdS(d)

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    We analyze the pattern of fields in d+1 dimensional anti-de Sitter space in terms of those in d dimensional anti-de Sitter space. The procedure, which is neither dimensional reduction nor dimensional compactification, is called dimensional degression. The analysis is performed group-theoretically for all totally symmetric bosonic and fermionic representations of the anti-de Sitter algebra. The field-theoretical analysis is done for a massive scalar field in AdS(d+d′^\prime) and massless spin one-half, spin one, and spin two fields in AdS(d+1). The mass spectra of the resulting towers of fields in AdS(d) are found. For the scalar field case, the obtained results extend to the shadow sector those obtained by Metsaev in [1] by a different method.Comment: 30 page

    Hyperfine structure of S-states in muonic deuterium

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    On the basis of quasipotential method in quantum electrodynamics we calculate corrections of order α5\alpha^5 and α6\alpha^6 to hyperfine structure of S-wave energy levels of muonic deuterium. Relativistic corrections, effects of vacuum polarization in first, second and third orders of perturbation theory, nuclear structure and recoil corrections are taken into account. The obtained numerical values of hyperfine splitting ΔEhfs(1S)=50.2814\Delta E^{hfs}(1S)=50.2814 meV (1S state) and ΔEhfs(2S)=6.2804\Delta E^{hfs}(2S)=6.2804 meV (2S state) represent reliable estimate for a comparison with forthcoming experimental data of CREMA collaboration. The hyperfine structure interval Δ12=8ΔEhfs(2S)−ΔEhfs(1S)=−0.0379\Delta_{12}=8\Delta E^{hfs}(2S)-\Delta E^{hfs}(1S)=-0.0379 meV can be used for precision check of quantum electrodynamics predictions for muonic deterium.Comment: 18 pages, 7 figure

    Exploring the S-Matrix of Massless Particles

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    We use the recently proposed generalised on-shell representation for scattering amplitudes and a consistency test to explore the space of tree-level consistent couplings in four-dimensional Minkowski spacetime. The extension of the constructible notion implied by the generalised on-shell representation, i.e. the possibility to reconstruct at tree level all the scattering amplitudes from the three-particle ones, together with the imposition of the consistency conditions at four-particle level, allow to rediscover all the known theories and their algebra structure, if any. Interestingly, this analysis seems to leave room for high-spin couplings, provided that at least the requirement of locality is weakened. We do not claim to have found tree-level consistent high-spin theories, but rather that our methods show signatures of them and very likely, with a suitable modification, they can be a good framework to perform a systematic search.Comment: 44 pages, 1 figur

    Radiative nonrecoil nuclear finite size corrections of order α(Zα)5\alpha(Z \alpha)^5 to the Lamb shift in light muonic atoms

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    On the basis of quasipotential method in quantum electrodynamics we calculate nuclear finite size radiative corrections of order α(Zα)5\alpha(Z \alpha)^5 to the Lamb shift in muonic hydrogen and helium. To construct the interaction potential of particles, which gives the necessary contributions to the energy spectrum, we use the method of projection operators to states with a definite spin. Separate analytic expressions for the contributions of the muon self-energy, the muon vertex operator and the amplitude with spanning photon are obtained. We present also numerical results for these contributions using modern experimental data on the electromagnetic form factors of light nuclei.Comment: 8 pages, 1 Figur

    Vibro-acoustics of porous materials - Waveguide modelling approach

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    DETRITAL ZIRCON AGES AND SOURCES OF MATERIAL FOR THE LOWER CAMBRIAN DEPOSITS OF THE MEL'GIN TROUGH OF THE BUREYA CONTINENTAL MASSIF

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    Bureya continental massif is one of the largest continental massifs in the eastern part of the Central Asian orogenic belt (CAOB) (Fig. 1), and knowledge of its geological structure is of fundamental importance in understanding the history of its formation.Bureya continental massif is one of the largest continental massifs in the eastern part of the Central Asian orogenic belt (CAOB) (Fig. 1), and knowledge of its geological structure is of fundamental importance in understanding the history of its formation

    Multiple ionization of neon by soft X-rays at ultrahigh intensity

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    At the free-electron laser FLASH, multiple ionization of neon atoms was quantitatively investigated at 93.0 eV and 90.5 eV photon energy. For ion charge states up to 6+, we compare the respective absolute photoionization yields with results from a minimal model and an elaborate description. Both approaches are based on rate equations and take into acccout a Gaussian spatial intensity distribution of the laser beam. From the comparison we conclude, that photoionization up to a charge of 5+ can be described by the minimal model. For higher charges, the experimental ionization yields systematically exceed the elaborate rate based prediction.Comment: 10 pages, 3 figure
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