7,123 research outputs found

    Neutrino and axion bounds from the globular cluster M5 (NGC 5904)

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    The red-giant branch (RGB) in globular clusters is extended to larger brightness if the degenerate helium core loses too much energy in "dark channels." Based on a large set of archival observations, we provide high-precision photometry for the Galactic globular cluster M5 (NGC 5904), allowing for a detailed comparison between the observed tip of the RGB with predictions based on contemporary stellar evolution theory. In particular, we derive 95% confidence limits of gae<4.3×10−13g_{ae}<4.3\times10^{-13} on the axion-electron coupling and μν<4.5×10−12 μB\mu_\nu<4.5\times10^{-12}\,\mu_{\rm B} (Bohr magneton μB=e/2me\mu_{\rm B}=e/2m_e) on a neutrino dipole moment, based on a detailed analysis of statistical and systematic uncertainties. The cluster distance is the single largest source of uncertainty and can be improved in the future.Comment: 5 pages, 2 figures, accepted for publication in Physical Review Letter

    Axion-electron coupling from the RGB tip of Globular Clusters

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    We present a preliminary study of the Globular Cluster RGB devoted to improve the available constraint for the axion-electron coupling. By means of multi-band IR photometry of the cluster M3 we obtain g_{ae}/10^{-13} < 2.57 (95\% C.L.).Comment: paper submitted to Proceedings of the 13th Patras Workshop on Axions, WIMPs and WISPs (Patras2017)

    Managing the necessary cross-disciplinary approach to organic farming research programmes: example of an organic bread programme.

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    This programme was developed within a cross-disciplinary approach resulting from five project proposals focusing on the organic wheat, flour and bread sector. More than 30 researchers from nine academic research laboratories, five technical centres, three development agencies and four industrial firms were involved in the project, covering a large area of expertise (from genetics to sociology). The programme adopted a reverse engineering approach, starting from consumer expectations and travelling, link-by-link, up the food chain. A qualitative study of consumer perception and expectations showed that organic bread was perceived as a natural, nourishing and healthy product, and that although its organoleptic characteristics (volume, texture, etc.) were a determining factor, they in no way totally accounted for the quality of the product. Nutritional value and safety must also be taken into consideration, especially in the case of occasional consumers. Based on this study, work was undertaken to find processing conditions to turn grain into flour and flour into bread, which would meet those expectations. New roller milling diagrams were developed at the industrial scale in order to produce flour with higher fibre and micronutrient contents. Studies of the bread-making process have shown that higher levels of lactic acid bacterium production in millstone flour are probably linked to its mineral content. A more acidic environment, due to sourdough fermentation, increases phytasic activity (improving digestibility) and increases mineral bioavailability, including magnesium. Based on those findings, prototype breads were developed and assessed by two panels of 60 people in two different regions of France. The results showed that it was possible to produce bread that satisfied consumers’ sensory and nutritional expectations by adapting the fractionation processes during bread-making according to the characteristics of the wheat. Finally, this programme resulted in a large number of publications and created a dynamic process between participants. It served as the backbone for several complementary satellite programmes that enhanced the original research while being integrated and supported by the project management committee

    CAST constraints on the axion-electron coupling

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    In non-hadronic axion models, which have a tree-level axion-electron interaction, the Sun produces a strong axion flux by bremsstrahlung, Compton scattering, and axio-recombination, the "BCA processes." Based on a new calculation of this flux, including for the first time axio-recombination, we derive limits on the axion-electron Yukawa coupling g_ae and axion-photon interaction strength g_ag using the CAST phase-I data (vacuum phase). For m_a < 10 meV/c2 we find g_ag x g_ae< 8.1 x 10^-23 GeV^-1 at 95% CL. We stress that a next-generation axion helioscope such as the proposed IAXO could push this sensitivity into a range beyond stellar energy-loss limits and test the hypothesis that white-dwarf cooling is dominated by axion emission
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