Sterile Neutrinos: An Introduction to Experiments

This paper is written as one chapter in a collection of essays on neutrino physics for beginning graduate students. The text presents important experimental methods and issues for those interested in searches for sterile neutrinos. Other essays in the collection, written by other authors, will cover introduction to neutrinos in the Standard Model, a description of the theory, and discussion of details of detectors, thus these aspects are not covered here. However, beyond these points, this represents a self-contained tutorial on experimental studies of sterile neutrino oscillations, covering such issues as signals vs. limits, designing experiments, and performing and interpreting global fits to the oscillation data.National Science Foundation (U.S.) (Grant 1505855)National Science Foundation (U.S.) (Grant 1505858)National Science Foundation (U.S.) (Grant 1404209

Extraits de l'évolution de l'entomologie appliquée au Québec : emphase sur la phytoprotection

Le développement de l’entomologie au Québec comme science naturelle a commencé avec des naturalistes érudits comme William Couper, Léon Provancher et Henry Lyman qui ont observé abondamment et décrit l’entomofaune du Québec, fondé des sociétés professionnelles et rédigé les premiers ouvrages scientifiques sur les insectes du Québec. Au début du XXe siècle, l’importance économique des plantes agricoles et des essences de coupes forestières a atteint un niveau favorisant la naissance de l’entomologie appliquée. Son développement initial est marqué par la fondation de la SPPQ, la création du premier programme d’études supérieures en entomologie, ainsi que le recrutement d’entomologistes professionnels dans les institutions publiques de protection des plantes contre les ravageurs. Les entomologistes en chef James Fletcher au gouvernement fédéral et Victor Huard au gouvernement provincial, ainsi que les professeurs William Lochhead du Collège Macdonald et Georges Maheux de l’École forestière de l’Université Laval, sont des figures remarquables de cette époque. Les entomologistes publient abondamment sur le cycle de vie des insectes nuisibles, sur les dommages causés et sur les moyens de lutte efficaces avec des insecticides encore primitifs et dangereux. Pendant plusieurs décennies, Ernest-Melville DuPorte se trouve au Collège Macdonald au centre des études supérieures et de la recherche en entomologie au Québec. Après la Seconde Guerre mondiale, la demande en denrées alimentaires et en fibre ligneuse croît à un rythme sans précédent, de même que la lutte aux ravageurs, à l’ère nouvelle des produits chimiques de synthèse, notamment des insecticides comme le DDT. En agriculture, les entomologistes actifs en phytoprotection se regroupent au laboratoire de recherche de Saint-Jean-sur-Richelieu et au Service de la protection des cultures du MAPAQ, ainsi que dans leurs stations de recherche de terrain. La recherche en entomologie forestière se développe à Québec autour du laboratoire fédéral des Laurentides et à la Faculté d’arpentage et de génie forestier (aujourd’hui la Faculté de foresterie, de géographie et de géomatique) de l’Université Laval. Sous la pression de l’industrie forestière, les arrosages aériens aux insecticides deviennent systématiques et sont surtout régis par l’abondance cyclique de la tordeuse des bourgeons de l’épinette. À la fin des années 1960, l’entomologie appliquée prend lentement un virage écologique, ouvert au contrôle naturel des ravageurs et aux idées de la résistance des plantes et de la stimulation de l’impact des agents biologiques de répression. La recherche et la formation aux études supérieures en entomologie connaissent un essor marqué dans les centres universitaires établis et nouvellement créés. La fin du XXe siècle est marquée par l’arrivée des plantes transgéniques résistantes aux ravageurs et les conséquences prévisibles du réchauffement climatique sur l’abondance et la diversité des ravageurs. L’entomologie comme activité scientifique professionnelle s’est enrichie de l’arrivée de nombreuses femmes dans les centres de recherche et les universités, bien qu’affectée par le ralentissement du recrutement d’entomologistes professionnels dans les services publics et les universités et l’incertitude des conditions économiques futures.The development of entomology as a natural science in Quebec first involved naturalist erudites such as William Couper, Léon Provancher and Henry Lyman, who abundantly observed and described the Quebec entomofauna, founded societies of professional entomologists, and wrote the first scientific documents about the insects of Quebec. At the turn of the 20th century, the economic importance of agricultural and forest products had reached a sufficient level for applied entomology to develop its own identity. This is evidenced by the birth of the Québec Society for the Protection of Plants, the creation of the first higher education program in entomology, and the establishment of professional entomologist positions in the plant protection services of the federal and provincial governments. Entomologists abundantly published on the life cycle of insect pests, their damages, and early efficient insect pest control using what were then primitive and dangerous insecticides. Entomologists in chief James Fletcher, at the federal level, and Victor Huard, at the provincial level, as well as entomology professors William Lochhead of Macdonald College and Georges Maheux of the École forestière de l’Université Laval, are important figures who initially guided the development of applied entomology in Quebec. For decades, Ernest-Melville DuPorte, while working at Macdonald College, was at the centre of higher education and fundamental research in entomology in Quebec. Following the Second World War, the demand for food products and wood fibre grew at an unprecedented rate, and so did the need to control insect pests, in the new era of synthetic chemicals such as the DDT insecticide. Entomologists active in agriculture were mainly regrouped around the Saint-Jean-sur-Richelieu Research Station and at the MAPAQ’s Service of Plant Protection, and at their experimental field stations. Research in forest entomology developed itself in Quebec City at the Laurentians federal laboratory and at the Faculté d’arpentage et de génie forestier (known today as the Faculté de foresterie, de géographie et de géomatique) de l’Université Laval. Due to pressure from the forest industry, the spraying of Quebec forests with chemical insecticides expanded systematically and, for decades, was mainly determined by the cyclic abundance of the spruce budworm. At the end of the 1960s, applied entomology in Quebec slowly took an ecological turn, marked by environmental concerns about chemical insecticides, more attention given to natural control, and a renewed interest in biological control agents. Fundamental research on insects and higher education in entomology expanded in both established and newly created university centres. The recent decades were marked by the arrival of genetically modified crops that are highly resistant to target pests, and the imminent consequences of global warming on the abundance and diversity of insect pests. Entomology as a professional activity benefited from the arrival of many women in research centres and universities; however, there is now some concern about the noticeable decline in the recruitment of specialized entomologists in public services and universities, and an uncertain economic future

First Constraints on the Complete Neutrino Mixing Matrix with a Sterile Neutrino

Neutrino oscillation models involving one extra mass eigenstate beyond the standard three (3+1) are fit to global short baseline experimental data and the recent IceCube ν[subscript μ] + [bar over v][subscript μ] disappearance search result. We find a best fit of Δm[subscript 41][superscript 2]=1.75  eV[superscript 2] with Δx[subscript null-min][superscript 2]/d.o.f. of 50.61/4. We find that the combined IceCube and short baseline data constrain θ[subscript 34] to <80°(<6°) at 90% C.L. for Δm[subscript 41][superscript 2]≈2(6)  eV[superscript 2], which is improved over present limits. Incorporating the IceCube information provides the first constraints on all entries of the 3+1 mixing matrix.National Science Foundation (U.S.) (Grant 1505858)National Science Foundation (U.S.) (Grant 1505855

Boosted dark matter at neutrino experiments

Current and future neutrino experiments can be used to discover dark matter, not only in searches for dark matter annihilating to neutrinos, but also in scenarios where dark matter itself scatters off standard model particles in the detector. In this work, we study the sensitivity of different neutrino detectors to a class of models called boosted dark matter, in which a subdominant component of a dark sector acquires a large Lorentz boost today through annihilation of a dominant component in a dark matter-dense region, such as the galactic Center or dwarf spheroidal galaxies. This analysis focuses on the sensitivity of different neutrino detectors, specifically the Cherenkov-based Super-K and the future argon-based DUNE to boosted dark matter that scatters off electrons. We study the dependence of the expected limits on the experimental features, such as energy threshold, volume and exposure in the limit of constant scattering amplitude. We highlight experiment-specific features that enable current and future neutrino experiments to be a powerful tool in finding signatures of boosted dark matter

The front-end of IsoDAR

The Isotope Decay-At-Rest (IsoDAR) experiment is a cyclotron based neutrino oscillation exper- iment that is capable of decisively searching for low-mass sterile neutrinos. This paper outlines two new approaches that the IsoDAR collaboration are pursuing in order to increase the amount of H + 2 captured in the cyclotron through innovations in the design of the front-end. A new dedicated multicusp ion source (MIST-1) is currently being commissioned and tested at the Plasma Science and Fusion Center (PSFC) at MIT. Based on previous results from this type of ion source, we ex- pect to be able to achieve an H+₂ current density that will be sufficient for the IsoDAR experiment. We also discuss the results of a new investigation into using a radio frequency quadrupole (RFQ) as a high-efficiency buncher to improve the injection efficiency into the cyclotron.National Science Foundation (U.S.) (Grant 1505858)National Science Foundation (U.S.) (Grant 1626069

Precision muon reconstruction in Double Chooz

We describe a muon track reconstruction algorithm for the reactor anti-neutrino experiment Double Chooz. The Double Chooz detector consists of two optically isolated volumes of liquid scintillator viewed by PMTs, and an Outer Veto above these made of crossed scintillator strips. Muons are reconstructed by their Outer Veto hit positions along with timing information from the other two detector volumes. All muons are fit under the hypothesis that they are through-going and ultrarelativistic. If the energy depositions suggest that the muon may have stopped, the reconstruction fits also for this hypothesis and chooses between the two via the relative goodness-of-fit. In the ideal case of a through-going muon intersecting the center of the detector, the resolution is ∼40 mm in each transverse dimension. High quality muon reconstruction is an important tool for reducing the impact of the cosmogenic isotope background in Double Chooz.National Science Foundation (U.S.)United States. Department of Energ

Michel electron reconstruction using cosmic-ray data from the MicroBooNE LArTPC

The MicroBooNE liquid argon time projection chamber (LArTPC) has been taking data at Fermilab since 2015 collecting, in addition to neutrino beam, cosmic-ray muons. Results are presented on the reconstruction of Michel electrons produced by the decay at rest of cosmic-ray muons. Michel electrons are abundantly produced in the TPC, and given their well known energy spectrum can be used to study MicroBooNE's detector response to low-energy electrons (electrons with energies up to ∼ 50 MeV). We describe the fully-automated algorithm developed to reconstruct Michel electrons, with which a sample of ∼ 14,000 Michel electron candidates is obtained. Most of this article is dedicated to studying the impact of radiative photons produced by Michel electrons on the accuracy and resolution of their energy measurement. In this energy range, ionization and bremsstrahlung photon production contribute similarly to electron energy loss in argon, leading to a complex electron topology in the TPC. By profiling the performance of the reconstruction algorithm on simulation we show that the ability to identify and include energy deposited by radiative photons leads to a significant improvement in the energy measurement of low-energy electrons. The fractional energy resolution we measure improves from over 30% to ∼ 20% when we attempt to include radiative photons in the reconstruction. These studies are relevant to a large number of analyses which aim to study neutrinos by measuring electrons produced by ν e interactions over a broad energy range. Keywords: Michel electrons, LArTPC, MicroBooN

The desktop muon detector: A simple, physics-motivated machine- and electronics-shop project for university students

This paper describes the construction of a desktop muon detector, an undergraduate-level physics project that develops machine-shop and electronics-shop technical skills. The desktop muon detector is a self-contained apparatus that employs a plastic scintillator as the detection medium and a silicon photomultiplier for light collection. This detector can be battery powered and is used in conjunction with the provided software. The total cost per detector is approximately $100. We describe physics experiments we have performed, and then suggest several other interesting measurements that are possible, with one or more desktop muon detectors.National Science Foundation (U.S.) (Grant 1505858

Sterile neutrino fits to short baseline data

Neutrino oscillation models involving extra mass eigenstates beyond the standard three (3+N) are fit to global short baseline experimental data. We find that 3+1 has a best fit of Δm[subscript 41][superscript 2] = 1.75 eV[superscript 2] with a Δχ[subscript null-min][superscript 2] (dof) of 52.34 (3). The 3+2 fit has a Δχ[subscript null-min][superscript 2] (dof) of 56.99 (7). For the first time, we show Bayesian credible intervals for a 3+1 model. These are found to be in agreement with frequentist intervals. The results of these new fits favor a higher Δm2 value than previous studies, which may have an impact on future sterile neutrino searches such as the Fermilab SBN program.National Science Foundation (U.S.) (Grant 1505858)National Science Foundation (U.S.) (Grant 1505855

The photomultiplier tube calibration system of the MicroBooNE experiment

We report on the design and construction of a LED-based fiber calibration system for large liquid argon time projection detectors. This system was developed to calibrate the optical systems of the MicroBooNE experiment. As well as detailing the materials and installation procedure, we provide technical drawings and specifications so that the system may be easily replicated in future LArTPC detectors.National Science Foundation (U.S.) (Grant PHY-1205175