We examine uncertainties in the analysis of the reactor neutrino anomaly, wherein it is suggested that only about 94% of the emitted antineutrino flux was detected in short baseline experiments. We ...find that the form of the corrections that lead to the anomaly are very uncertain for the 30% of the flux that arises from forbidden decays. This uncertainty was estimated in four ways, is as large as the size of the anomaly, and is unlikely to be reduced without accurate direct measurements of the antineutrino flux. Given the present lack of detailed knowledge of the structure of the forbidden transitions, it is not possible to convert the measured aggregate fission beta spectra to antineutrino spectra to the accuracy needed to infer an anomaly. Neutrino physics conclusions based on the original anomaly need to be revisited, as do oscillation analyses that assumed that the antineutrino flux is known to better than approximately 4%.
We investigate the recent Daya Bay results on the changes in the antineutrino flux and spectrum with the burnup of the reactor fuel. We find that the discrepancy between current model predictions and ...the Daya Bay results can be traced to the original measured ^{235}U/^{239}Pu ratio of the fission β spectra that were used as a base for the expected antineutrino fluxes. An analysis of the antineutrino spectra that is based on a summation over all fission fragment β decays, using nuclear database input, explains all of the features seen in the Daya Bay evolution data. However, this summation method still allows for an anomaly. We conclude that there is currently not enough information to use the antineutrino flux changes to rule out the possible existence of sterile neutrinos.
The MiniBooNE experiment at Fermilab reports a total excess of 638.0 ± 52.1 (stat .) ± 122.2 (syst.) electronlike events from a data sample corresponding to 18.75 × 10 20 protons-on-target in ...neutrino mode, which is a 46% increase in the data sample with respect to previously published results and 11.27 × 10 20 protons-on-target in antineutrino mode. The overall significance of the excess, 4.8σ, is limited by systematic uncertainties, assumed to be Gaussian, as the statistical significance of the excess is 12.2σ. The additional statistics allow several studies to address questions on the source of the excess. First, we provide two-dimensional plots in visible energy and the cosine of the angle of the outgoing lepton, which can provide valuable input to models for the event excess. Second, we test whether the excess may arise from photons that enter the detector from external events or photons exiting the detector from π 0 decays in two model independent ways. Beam timing information shows that almost all of the excess is in time with neutrinos that interact in the detector. The radius distribution shows that the excess is distributed throughout the volume, while tighter cuts on the fiducial volume increase the significance of the excess. The data likelihood ratio disfavors models that explain the event excess due to entering or exiting photons.
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 1.86 × 1020 ...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 MeV c−2 . 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 4.6σ.
The Coulomb enhancement of low energy electrons in nuclear beta decay generates sharp cutoffs in the accompanying antineutrino spectrum at the beta decay endpoint energies. It has been conjectured ...that these features will interfere with measuring the effect of a neutrino mass hierarchy on an oscillated nuclear reactor antineutrino spectrum. These sawtoothlike features will appear in detailed reactor antineutrino spectra, with characteristic energy scales similar to the oscillation period critical to neutrino mass hierarchy determination near a 53 km baseline. However, these sawtoothlike distortions are found to contribute at a magnitude of only a few percent relative to the mass hierarchy-dependent oscillation pattern in Fourier space. In the Fourier cosine and sine transforms, the features that encode a neutrino mass hierarchy dominate by over sixteen (thirty-three) times in prominence to the maximal contribution of the sawtoothlike distortions from the detailed energy spectrum, given 3.2%/Evis/MeV (perfect) detector energy resolution. The effect of these distortions is shown to be negligible even when the uncertainties in the reactor spectrum, oscillation parameters, and counting statistics are considered. This result is shown to hold even when the opposite hierarchy oscillation patterns are nearly degenerate in energy space, if energy response nonlinearities are controlled to below 0.5%. Therefore with accurate knowledge of detector energy response, the sawtoothlike features in reactor antineutrino spectra will not significantly impede neutrino mass hierarchy measurements using reactor antineutrinos.
The MiniBooNE-DM Collaboration searched for vector-boson mediated production of dark matter using the Fermilab 8-GeV Booster proton beam in a dedicated run with 1.86×10^{20} protons delivered to a ...steel beam dump. The MiniBooNE detector, 490 m downstream, is sensitive to dark matter via elastic scattering with nucleons in the detector mineral oil. Analysis methods developed for previous MiniBooNE scattering results were employed, and several constraining data sets were simultaneously analyzed to minimize systematic errors from neutrino flux and interaction rates. No excess of events over background was observed, leading to a 90% confidence limit on the dark matter cross section parameter, Y=ε^{2}α_{D}(m_{χ}/m_{V})^{4}≲10^{-8}, for α_{D}=0.5 and for dark matter masses of 0.01<m_{χ}<0.3 GeV in a vector portal model of dark matter. This is the best limit from a dedicated proton beam dump search in this mass and coupling range and extends below the mass range of direct dark matter searches. These results demonstrate a novel and powerful approach to dark matter searches with beam dump experiments.
The study of neutrino oscillations has necessitated a new generation of neutrino experiments that are exploring neutrino-nuclear scattering processes. We focus in particular on charged-current ...quasi-elastic scattering, a particularly important channel that has been extensively investigated both in the bubble-chamber era and by current experiments. Recent results have led to theoretical reexamination of this process. We review the standard picture of quasi-elastic scattering as developed in electron scattering, review and discuss experimental results, and discuss additional nuclear effects such as exchange currents and short-range correlations that may play a significant role in neutrino-nucleus scattering.
Purpose
Globally, lung cancer is the most common cancer and the leading cause of cancer death. Problematically, there is a wide variation in the management and survival for people with lung cancer ...and there is limited understanding of the reasons for these variations. To date, the views of health professionals across relevant disciplines who deliver such care are largely absent. The present study describes Australian health professionals’ views about barriers to lung cancer care to help build a research and action agenda for improving lung cancer outcomes.
Methods
Qualitative semi-structured interviews were undertaken with a multidisciplinary group of 31 Australian health professionals working in lung cancer care for an average of 16 years (range 1–35 yrs.; SD = 10.2) seeing a mean of 116 patients annually.
Results
Three superordinate themes were identified: illness representations, cultural influences, and health system context. Illness representations included three themes: symptoms attributed as smoking-related but not cancer, health-related stigma, and therapeutic nihilism. Cultural influence themes included Indigenous health care preferences, language and communication, and sociodemographic factors. Health system context included lack of regional services and distance to treatment, poor care coordination, lack of effective screening methods, and health professional behaviours.
Conclusions
Fractured and locally isolated approaches routinely confound responses to the social, cultural and health system complexities that surround a diagnosis of lung cancer and subsequent treatment. Improving outcomes for this disadvantaged patient group will require government, health agencies, and the community to take an aggressive, integrated approach balancing health policy, treatment priorities, and societal values.
The Australian Burden of Disease Study has shown that cancer is the single most important entity responsible for the greatest cause of health burden in Australia. Unfortunately, Aboriginal and Torres ...Strait Islander peoples experience a greater burden of this disease, with cancer of the lung, breast, bowel and prostrate being the most common. Lip, oral cavity and pharyngeal cancer incidence is rapidly rising globally and is now the sixth most common cancer in Australia. This paper aims to summarize, for the first time, the incidence and prevalence trends of lip, oral cavity and pharyngeal cancers in Aboriginal and Torres Strait Islander Australians.
Data were obtained from the Australian Cancer Database (ACD), which is compiled at the Australian Institute of Health and Welfare (AIHW) from 1999 to 2018 to estimate the incidence and prevalence of certain head and neck cancers (ICD-10 codes C00-C10, C14). The other variables requested were age groups and sex.
Results were stratified by ICD-10 code, sex and age group at diagnosis and time period (i.e. grouped years of diagnosis). The total incidence of lip, oral cavity and pharyngeal cancers increased by 1.3 times from 1999 to 2008 (107/100 000) to 2009-2018 (135/100 000). The overall 5-year prevalence of lip, oral cavity and pharyngeal cancers was 0.17% (0.24% for men and 0.09% for women).
The significantly increased incidence of lip, oral cavity and pharyngeal cancers in Aboriginal and Torres Strait Islander peoples in Australia is concerning and should be explored. A targeted, comprehensive and culturally safe model of care for Aboriginal and Torres Strait Islander peoples with lip, oral cavity and pharyngeal cancers is imperative.
Purpose
In Australia, Aboriginal and Torres Strait Islander peoples (First Nations population) often have low overall cancer survival, as do all residents of geographically remote areas. This study ...aimed to quantify the survival disparity between First Nations and other Queenslanders for 12 common cancer types by remoteness areas.
Methods
For all Queensland residents aged 20–89 years diagnosed with a primary invasive cancer during 1997–2016, we ran flexible parametric survival models incorporating age, First Nations status, sex, diagnosis time period, area-level socioeconomic status, remoteness categories and where appropriate, broad cancer type. Three survival measures were predicted: cause-specific survival, survival differences and the comparative survival ratio, each standardised to First Nations peoples’ covariate distributions.
Results
The standardised five-year cause-specific cancer survival was 60% for urban First Nations and 65% for other Queenslanders, while remote residents were 54% (First Nations) and 58% (other). The absolute survival differential between First Nations and other Queenslanders was often similar, regardless of remoteness of residence. The greatest absolute difference in five-year standardised cancer survival was for head and neck cancers, followed by cervical cancer.
The five-year comparative survival ratio (First Nations: other Queenslanders) for urban cancer patients was 0.91 (95% CI 0.90–0.93), similar to outer regional, inner regional and remote areas. The greatest comparative survival differential was for oesophageal cancer.
Conclusion
First Nations’ survival inequalities are largely independent of geographical remoteness. It remains a priority to determine the contribution of other potential factors such as the availability of culturally acceptable diagnostic, management and/or support services.
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