39,702 research outputs found

    Sharp de Rham realization

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    We introduce the "sharp" (universal) extension of a 1-motive (with additive factors and torsion) over a field of characteristic zero. We define the "sharp de Rham realization" by passing to the Lie-algebra. Over the complex numbers we then show a (sharp de Rham) comparison theorem in the category of formal Hodge structures. For a free 1-motive along with its Cartier dual we get a canonical connection on their sharp extensions yielding a perfect pairing on sharp realizations. We thus provide "one-dimensional sharp de Rham cohomology" of algebraic varieties.Comment: 30 page

    On the Deligne--Beilinson cohomology sheaves

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    We are showing that the Deligne--Beilinson cohomology sheaves Hq+1(Z(q)D){\cal H}^{q+1}({\bf Z}(q)_{\cal D}) are torsion free by assuming Kato's conjectures hold true for function fields. This result is `effective' for q=2q=2; in this case, by dealing with `arithmetic properties' of the presheaves of mixed Hodge structures defined by singular cohomology, we are able to give a cohomological characterization of the Albanese kernel for surfaces with pg=0p_g=0.Comment: 12 pages, LaTeX 2.0

    The Higgs mass as a function of the compactification scale

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    We calculate to a few percent precision the Higgs potential in a model with supersymmetry broken by boundary conditions on an extra-dimension, compactified to a segment of length LL, and a top quark quasi-localized on one of the two boundaries. 1/L alone, in the range 2-4 TeV, determines the Higgs mass, in the range 110-125 GeV, and the spectrum of gauginos, higgsinos and of the third-generation squarks. Lower values of 1/L cannot be excluded, with a progressive delocalization of the top quark.Comment: 22 pages, 6 figure

    Expectations for LHC from Naturalness: Modified vs. SM Higgs Sector

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    Common lore has it that naturalness of electroweak breaking in the SM requires new physics (NP) at Lambda < 2-3 TeV, hopefully within the reach of LHC. Moreover the Higgs should be light (m_h < 219 GeV) to pass electroweak precision tests (EWPT). However one should be prepared for "unexpected" (although admittedly unpleasant) results at LHC, i.e. no NP and/or a heavy Higgs. We revisit recent attempts to accommodate this by modifying the SM Higgs sector (using 2-Higgs-doublet models). We find that these models do not improve the naturalness of the SM, and so they do not change the expectations of observing NP at LHC. We also stress that a heavy SM Higgs would not be evidence in favour of a modified Higgs sector, provided certain higher order operators influence EWPT. On the other hand, we show that NP can escape LHC detection without a naturalness price, and with the pure SM as the effective theory valid at LHC energies, simply if the cut-off for top loops is slightly lower than for Higgs loops.Comment: 37 pages, LaTeX, 13 figure

    Study of the 16O(p,gamma) Reaction at Astrophysical Energies

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    The Feshbach theory of the optical potential naturally leads to a microscopic description of scattering in terms of the many-body self-energy. We consider a recent calculation of this quantity for 16O and study the possibility of applying it at astrophysical energies. The results obtained for the phase shifts and the 16O(p,\gamma) capture suggest that such studies are feasible but the calculations require some improvement geared to this specific task.Comment: 4 pages, 3 figures; Proceedings of Nuclei In The Cosmos VIII, to appear in Nucl. Phys.

    The importance of Enrichment Factor (EF) and Geoaccumulation Index (Igeo) to evaluate the soil contamination

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    Heavy metals are natural constituents of soils and their concentration varies depending on parental materials. In the last years, the content of heavy metal in soils has increased due to human activities as: distribution of fertilizers, pesticides, industries, waste disposal and air pollution. Due to these activities the life capacity of soils decreased; especially where the natural background is already high because of natural parental material richness in heavy metal. As a matter of fact it is very important to distinguish between the natural background values and anthropogenic inputs, and to understand that the background values change from area to area and with the scale of the area investigated. There is currently a wide variety of methods used to evaluate soil contamination. To evaluate the soil contamination rate different indexes like Enrichment Factor (EF) and geoaccumulation index (Igeo) can be applied. These indexes are used to assess the presence and intensity of anthropogenic contaminant deposition on surface soil

    Electroweak Corrections

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    The test of the electroweak corrections has played a major role in providing evidence for the gauge and the Higgs sectors of the Standard Model. At the same time the consideration of the electroweak corrections has given significant indirect information on the masses of the top and the Higgs boson before their discoveries and important orientation/constraints on the searches for new physics, still highly valuable in the present situation.The progression of these contributions is reviewed.Comment: 14 pages, 3 figures, a contribution to "The Standard Theory up to the Higgs discovery - 60 years of CERN

    Isotopes in hydrology and hydrogeology

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    The structure, status, and processes of the groundwater system, which can only be acquired through scientific research efforts, are critical aspects of water resource management. Isotope hydrology and hydrogeology is a genuinely interdisciplinary science. It developed from the application of methods evolved in physics (analytical techniques) to problems of Earth and the environmental sciences since around the 1950s. In this regard, starting from hydrogeochemical data, stable and radioactive isotope data provide essential tools in support of water resource management. The inventory of stable isotopes, which has significant implications for water resources management, has grown in recent years. Methodologies based on the use of isotopes in a full spectrum of hydrological problems encountered in water resource assessment, development, and management activities are already scientifically established and are an integral part of many water resource investigations and environmental studies. The driving force behind this Special Issue was the need to point the hydrological and water resource management societies in the direction of up-to-date research and best practices
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