Hadron mass corrections in semi-inclusive deep-inelastic scattering

The spin-dependent cross sections for semi-inclusive lepton-nucleon scattering are derived in the framework of collinear factorization, including the effects of masses of the target and produced hadron at finite momentum transfer squared Q^2. At leading order the cross sections factorize into products of parton distribution and fragmentation functions evaluated in terms of new, mass-dependent scaling variables. The size of the hadron mass corrections is estimated at kinematics relevant for future semi-inclusive deep-inelastic scattering experiments.Comment: 28 pages, 12 figures, published versio

Physics Potential of Very Intense Conventional Neutrino Beams

The physics potential of high intensity conventional beams is explored. We consider a low energy super beam which could be produced by a proposed new accelerator at CERN, the Super Proton Linac. Water Cherenkov and liquid oil scintillator detectors are studied as possible candidates for a neutrino oscillation experiment which could improve our current knowledge of the atmospheric parameters and measure or severely constrain the parameter connecting the atmospheric and solar realms. It is also shown that a very large water detector could eventually observe leptonic CP violation. The reach of such an experiment to the neutrino mixing parameters would lie in-between the next generation of neutrino experiments (MINOS, OPERA, etc) and a future neutrino factory.Comment: Talk given at the Venice Conference on Neutrino Telescopes, Venice, March, 200

Physics Potential of the SPL Super Beam

Performances of a neutrino beam generated by the CERN SPL proton driver are computed considering a 440 kton water Cerenkov detector at 130 km from the target. $\theta_{13}$ sensitivity down to $1.2^\circ$ and a $\delta$ sensitivity comparable to a Neutrino Factory, for $\theta_{13} \geq 3^\circ$, are within the reach of such a project.Comment: Invited talk at the Nufact02 Workshop, Imperial College of Science, Technology and Medicine, London, July 200

Searching for hexagonal analogues of the half-metallic half-Heusler XYZ compounds

The XYZ half-Heusler crystal structure can conveniently be described as a tetrahedral zinc blende YZ structure which is stuffed by a slightly ionic X species. This description is well suited to understand the electronic structure of semiconducting 8-electron compounds such as LiAlSi (formulated Li$^+$[AlSi]$^-$) or semiconducting 18-electron compounds such as TiCoSb (formulated Ti$^{4+}$[CoSb]$^{4-}$). The basis for this is that [AlSi]$^-$ (with the same electron count as Si$_2$) and [CoSb]$^{4-}$ (the same electron count as GaSb), are both structurally and electronically, zinc-blende semiconductors. The electronic structure of half-metallic ferromagnets in this structure type can then be described as semiconductors with stuffing magnetic ions which have a local moment: For example, 22 electron MnNiSb can be written Mn$^{3+}$[NiSb]$^{3-}$. The tendency in the 18 electron compound for a semiconducting gap -- believed to arise from strong covalency -- is carried over in MnNiSb to a tendency for a gap in one spin direction. Here we similarly propose the systematic examination of 18-electron hexagonal compounds for semiconducting gaps; these would be the "stuffed wurtzite" analogues of the "stuffed zinc blende" half-Heusler compounds. These semiconductors could then serve as the basis for possibly new families of half-metallic compounds, attained through appropriate replacement of non-magnetic ions by magnetic ones. These semiconductors and semimetals with tunable charge carrier concentrations could also be interesting in the context of magnetoresistive and thermoelectric materials.Comment: 11 pages, 6 figures, of which 4 are colou

Brain-specific tropomyosins TMBr-1 and TMBr-3 have distinct patterns of expression during development and in adult brain

In this study we report on the developmental and regional expression of two brain-specific isoforms of tropomyosin, TMBr-1 and TMBr-3, that are generated from the rat alpha-tropomyosin gene via the use of alternative promoters and alternative RNA splicing. Western blot analysis using an exon-specific peptide polyclonal antibody revealed that the two isoforms are differentially expressed in development with TMBr-3 appearing in the embryonic brain at 16 days of gestation, followed by the expression of TMBr-1 at 20 days after birth. TMBr-3 was detected in all brain regions examined, whereas TMBr-1 was detected predominantly in brain areas that derived from the prosencephalon. Immunocytochemical studies on mixed primary cultures made from rat embryonic midbrain indicate that expression of the brain-specific epitope is restricted to neurons. The developmental pattern and neuronal localization of these forms of tropomyosin suggest that these isoforms have a specialized role in the development and plasticity of the nervous system

Possible Effects of Quantum Mechanics Violation Induced by Certain Quantum Gravity on Neutrino Oscillations

In this work we tried extensively to apply the EHNS postulation about the quantum mechanics violation effects induced by the quantum gravity of black holes to neutrino oscillations. The possibilities for observing such effects in the neutrino experiments (in progress and/or accessible in the near future) were discussed. Of them, an interesting one was outlined specially.Comment: 18 pages, 0 figure, (1 REVTeX file