Light new physics in coherent neutrino-nucleus scattering experiments

Experiments aiming to detect coherent neutrino-nucleus scattering present opportunities to probe new light weakly-coupled states, such as sub-GeV mass dark matter, in several extensions of the Standard Model. These states can be produced along with neutrinos in the collisions of protons with the target, and their production rate can be enhanced if there exists a light mediator produced on-shell. We analyze the sensitivity reach of several proposed experiments to light dark matter interacting with the Standard Model via a light vector mediator coupled to the electromagnetic current. We also determine the corresponding sensitivity to massless singlet neutrino-type states with interactions mediated by the baryon number current. In both cases we observe that proposed coherent neutrino-nucleus scattering experiments, such as COHERENT at the SNS and CENNS at Fermilab, will have sensitivity well beyond the existing limits.Comment: 7 pages, 4 figure

Signatures of sub-GeV dark matter beams at neutrino experiments

We study the high-luminosity fixed-target neutrino experiments at MiniBooNE, MINOS and T2K and analyze their sensitivity to light stable states, focusing on MeV--GeV scale dark matter. Thermal relic dark matter scenarios in the sub-GeV mass range require the presence of light mediators, whose coupling to the Standard Model facilitates annihilation in the early universe and allows for the correct thermal relic abundance. The mediators in turn provide a production channel for dark matter at colliders or fixed targets, and as a consequence the neutrino beams generated at fixed targets may contain an additional beam of light dark matter. The signatures of this beam include elastic scattering off electrons or nucleons in the (near-)detector, which closely mimics the neutral current scattering of neutrinos. We determine the event rate at modern fixed target facilities and the ensuing sensitivity to sub-GeV dark matter.Comment: 18 pages, 13 figures, revtex4-

An evaluation of the IDEEA™ activity monitor for estimating energy expenditure

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Measuring the difference between actual and reported food intakes in the context of energy balance under laboratory conditions

Acknowledgements The present study was funded by the Food Standards Agency, UK. The Food Standards Agency had no role in the design, analysis or writing of this article. The authors’ responsibilities were as follows: R. J. S., L. M. O’R. and G. W. H. designed the research; L. M. O’R. and Z. F. conducted the research and analysed the data; G. W. H. performed the statistical analyses; P. R. carried out the DLW analysis; R. J. S. had primary responsibility for the final content; R. J. S., L. M. O’R., Z. F., S. W. and M. B. E. L. wrote the paper.Peer reviewedPublisher PD

Enhanced signal of astrophysical tau neutrinos propagating through Earth

Earth absorbs \nue and \numu of energies above about 100 TeV. As is well-known, although \nutau will also disappear through charged-current interactions, the \nutau flux will be regenerated by prompt tau decays. We show that this process also produces relatively large fluxes of secondary \nube and \nubmu, greatly enhancing the detectability of the initial \nutau. This is particularly important because at these energies \nutau is a significant fraction of the expected astrophysical neutrino flux, and only a tiny portion of the atmospheric neutrino flux.Comment: Four pages, two inline figure

A Novel Approach to Small Form-Factor Spacecraft Structures for Usage in Precision Optical Payloads

Precision optical payloads will soon experience a boom in manufacturing scale with the onset of proliferated satellite constellation concepts. Presently, the cost of assembly for a single unit can reach upwards of $500,000. Reduction in recurring engineering and assembly complexity can reduce this figure by up to two orders of magnitude. This paper discusses one potential solution which relies on consistent structural components that are easily manufactured in bulk quantities to facilitate general uses while also enabling high-precision mounting in designated payload slots. This proposed approach combines standardized struts and panels able to be connected and stacked in a variety of ways to form a modular structure from 1U subsections. For the subsections in need of higher precision, slots are milled and reamed from the same standard panel. Within these slots, card-like brackets are mounted to within 10 micrometer precision with the use of low-tolerance gauge spheres. A technique called “screw-pulling” secures these brackets such that the gauge spheres act as nearly single-point-of-contact datums. This approach allows payloads to be tested externally with minimal alignment shifts when re-integrated into the structure and is demonstrated with a 2.2 μm pixel size CMOS sensor and a 23 mm focal length lens

Observing a light dark matter beam with neutrino experiments

We consider the sensitivity of fixed-target neutrino experiments at the luminosity frontier to light stable states, such as those present in models of MeV-scale dark matter. To ensure the correct thermal relic abundance, such states must annihilate via light mediators, which in turn provide an access portal for direct production in colliders or fixed targets. Indeed, this framework endows the neutrino beams produced at fixed-target facilities with a companion `dark matter beam', which may be detected via an excess of elastic scattering events off electrons or nuclei in the (near-)detector. We study the high luminosity proton fixed-target experiments at LSND and MiniBooNE, and determine that the ensuing sensitivity to light dark matter generally surpasses that of other direct probes. For scenarios with a kinetically-mixed U(1)' vector mediator of mass m_V, we find that a large volume of parameter space is excluded for m_DM ~ 1-5 MeV, covering vector masses 2 m_DM < m_V < m_eta and a range of kinetic mixing parameters reaching as low as kappa ~ 10^{-5}. The corresponding MeV-scale dark matter scenarios motivated by an explanation of the galactic 511 keV line are thus strongly constrained.Comment: 19 pages, 5 figures; v2: typos corrected, to appear in Phys. Rev. D; v3: note added clarifying the parameter range excluded by LSN