35 research outputs found
Observation of a Significant Excess of Electron-Like Events in the MiniBooNE Short-Baseline Neutrino Experiment
The MiniBooNE experiment at Fermilab reports results from an analysis of appearance data from protons on target in neutrino mode, an increase of approximately a factor of two over previously reported results. A charged-current quasi-elastic event excess of events () is observed in the energy range $200E_\nu^{QE
Dark matter search in nucleon, pion, and electron channels from a proton beam dump with MiniBooNE
A search for sub-GeV dark matter produced from collisions of the Fermilab 8
GeV Booster protons with a steel beam dump was performed by the MiniBooNE-DM
Collaboration using data from protons on target in a
dedicated run. The MiniBooNE detector, consisting of 818 tons of mineral oil
and located 490 meters downstream of the beam dump, is sensitive to a variety
of dark matter initiated scattering reactions. Three dark matter interactions
are considered for this analysis: elastic scattering off nucleons, inelastic
neutral pion production, and elastic scattering off electrons. Multiple data
sets were used to constrain flux and systematic errors, and time-of-flight
information was employed to increase sensitivity to higher dark matter masses.
No excess from the background predictions was observed, and 90 confidence
level limits were set on the vector portal and leptophobic dark matter models.
New parameter space is excluded in the vector portal dark matter model with a
dark matter mass between 5 and 50. The reduced neutrino
flux allowed to test if the MiniBooNE neutrino excess scales with the
production of neutrinos. No excess of neutrino oscillation events were measured
ruling out models that scale solely by number of protons on target independent
of beam configuration at 4.6.Comment: 19 pages, 25 figures, Data release:
http://www-boone.fnal.gov/for_physicists/data_release/dark_matter_prd/ v2
Updated to published versio
Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases
The production of peroxide and superoxide is an inevitable consequence of
aerobic metabolism, and while these particular "reactive oxygen species" (ROSs)
can exhibit a number of biological effects, they are not of themselves
excessively reactive and thus they are not especially damaging at physiological
concentrations. However, their reactions with poorly liganded iron species can
lead to the catalytic production of the very reactive and dangerous hydroxyl
radical, which is exceptionally damaging, and a major cause of chronic
inflammation. We review the considerable and wide-ranging evidence for the
involvement of this combination of (su)peroxide and poorly liganded iron in a
large number of physiological and indeed pathological processes and
inflammatory disorders, especially those involving the progressive degradation
of cellular and organismal performance. These diseases share a great many
similarities and thus might be considered to have a common cause (i.e.
iron-catalysed free radical and especially hydroxyl radical generation). The
studies reviewed include those focused on a series of cardiovascular, metabolic
and neurological diseases, where iron can be found at the sites of plaques and
lesions, as well as studies showing the significance of iron to aging and
longevity. The effective chelation of iron by natural or synthetic ligands is
thus of major physiological (and potentially therapeutic) importance. As
systems properties, we need to recognise that physiological observables have
multiple molecular causes, and studying them in isolation leads to inconsistent
patterns of apparent causality when it is the simultaneous combination of
multiple factors that is responsible. This explains, for instance, the
decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference