We present a measurement of neutral pion production in charged-current interactions using data recorded with the MicroBooNE detector exposed to Fermilab's booster neutrino beam. The signal comprises ...one muon, one neutral pion, any number of nucleons, and no charged pions. Studying neutral pion production in the MicroBooNE detector provides an opportunity to better understand neutrino-argon interactions, and is crucial for future accelerator-based neutrino oscillation experiments. Using a dataset corresponding to \(6.86 \times 10^{20}\) protons on target, we present single-differential cross sections in muon and neutral pion momenta, scattering angles with respect to the beam for the outgoing muon and neutral pion, as well as the opening angle between the muon and neutral pion. Data extracted cross sections are compared to generator predictions. We report good agreement between the data and the models for scattering angles, except for an over-prediction by generators at muon forward angles. Similarly, the agreement between data and the models as a function of momentum is good, except for an underprediction by generators in the medium momentum ranges, \(200-400\) MeV for muons and \(100-200\) MeV for pions.
Charged-current neutrino interactions with final states containing zero mesons and at least one proton are of high interest for current and future accelerator-based neutrino oscillation experiments. ...Using the Booster Neutrino Beam and the MicroBooNE detector at Fermi National Accelerator Laboratory, we have obtained the first double-differential cross section measurements of this channel for muon neutrino scattering on an argon target with a proton momentum threshold of 0.25 GeV/c. We also report a flux-averaged total cross section of \(\sigma = (11.8 \pm 1.2) \times 10^{-38}\) cm\(^2\) / Ar and several single-differential measurements which extend and improve upon previous results. Statistical and systematic uncertainties are quantified with a full treatment of correlations across 359 kinematic bins, including correlations between distributions describing different observables. The resulting data set provides the most detailed information obtained to date for testing models of mesonless neutrino-argon scattering.
NEXT-100 is currently being constructed at the Laboratorio Subterráneo de Canfranc in the Spanish Pyrenees and will search for neutrinoless double beta decay using a high-pressure gaseous time ...projection chamber (TPC) with 100 kg of xenon. Charge amplification is carried out via electroluminescence (EL) which is the process of accelerating electrons in a high electric field region causing secondary scintillation of the medium proportional to the initial charge. The NEXT-100 EL and cathode regions are made from tensioned hexagonal meshes of 1 m diameter. This paper describes the design, characterization, and installation of these parts for NEXT-100. Simulations of the electric field are performed to model the drift and amplification of ionization electrons produced in the detector under various EL region alignments and rotations. Measurements of the electrostatic breakdown voltage in air characterize performance under high voltage conditions and identify breakdown points. The electrostatic deflection of the mesh is quantified and fit to a first-principles mechanical model. Measurements were performed with both a standalone test EL region and with the NEXT-100 EL region before its installation in the detector. Finally, we describe the parts as installed in NEXT-100, following their deployment in Summer 2023.
Noble element time projection chambers are a leading technology for rare event detection in physics, such as for dark matter and neutrinoless double beta decay searches. Time projection chambers ...typically assign event position in the drift direction using the relative timing of prompt scintillation and delayed charge collection signals, allowing for reconstruction of an absolute position in the drift direction. In this paper, alternate methods for assigning event drift distance via quantification of electron diffusion in a pure high pressure xenon gas time projection chamber are explored. Data from the NEXT-White detector demonstrate the ability to achieve good position assignment accuracy for both high- and low-energy events. Using point-like energy deposits from \(^{83\mathrm{m}}\)Kr calibration electron captures (\(E\sim45\)keV), the position of origin of low-energy events is determined to \(2~\)cm precision with bias \(< 1\)mm. A convolutional neural network approach is then used to quantify diffusion for longer tracks (E\(\geq\)1.5MeV), yielding a precision of 3cm on the event barycenter. The precision achieved with these methods indicates the feasibility energy calibrations of better than 1% FWHM at Q\(_{\beta\beta}\) in pure xenon, as well as the potential for event fiducialization in large future detectors using an alternate method that does not rely on primary scintillation.
We report the first double-differential cross section measurement of neutral-current neutral pion (NC\(\pi^0\)) production in neutrino-argon scattering, as well as single-differential measurements of ...the same channel in terms of final states with and without protons. The kinematic variables of interest for these measurements are the \(\pi^0\) momentum and the \(\pi^0\) scattering angle with respect to the neutrino beam. A total of 4971 candidate NC\(\pi^0\) events fully-contained within the MicroBooNE detector are selected using data collected at a mean neutrino energy of \(\sim 0.8\) GeV from \(6.4\times10^{20}\) protons on target from the Booster Neutrino Beam at the Fermi National Accelerator Laboratory. After extensive data-driven model validation to ensure unbiased unfolding, the Wiener-SVD method is used to extract nominal flux-averaged cross sections. The results are compared to predictions from commonly used neutrino event generators, which tend to overpredict the measured NC\(\pi^0\) cross section, especially in the 0.2-0.5 GeV/c \(\pi^0\) momentum range, at forward scattering angles, and when at least one proton is present in the final state. These measurements show sensitivity to a variety of features that complicate the description of NC\(\pi^0\) production including the form factors describing the elementary neutrino interaction and the final state interactions of the outgoing particles in the residual argon nucleus. This data will help improve the modeling of NC\(\pi^0\) production, which represents a major background in measurements of charge-parity violation in the neutrino sector and in searches for new physics beyond the Standard Model.
We report a search for nonstandard neutrino interactions (NSI) using eight years of TeV-scale atmospheric muon neutrino data from the IceCube Neutrino Observatory. By reconstructing incident energies ...and zenith angles for atmospheric neutrino events, this analysis presents unified confidence intervals for the NSI parameter \(\epsilon_{\mu \tau}\). The best-fit value is consistent with no NSI at a p-value of 25.2%. With a 90% confidence interval of \(-0.0041 \leq \epsilon_{\mu \tau} \leq 0.0031\) along the real axis and similar strength in the complex plane, this result is the strongest constraint on any NSI parameter from any oscillation channel to date.
•A screening methodology for thermochemical materials based on a mineral classification is firstly introduced.•Potential reaction systems are experimentally identified, which have yet not been ...considered.•Two reaction systems are identified to match the defined screening criteria.•The hysteresis at a defined water vapor partial pressure is determined.•Cycling stability of the system CaZn2(PO4)2·2H2O / CaZn2(PO4)2·H2O is foremost proven.
Thermochemical energy storage and conversion is yet considered as key technology enhancing the efficiency of energy production and utilization from renewables. Recently, several search algorithms and screening approaches for new materials for thermochemical energy storage and conversion have been published. Since respective reaction systems have to match numerous requirements, the demand for suitable materials in the low, middle and high temperature range is quite significant. However, recent works on reversible de- and rehydrations for application in the middle temperature range from 100 °C–400 °C are predominantly restricted to simple, binary compounds containing water of crystallization. Within the scope of the present work, a new search methodology based on a mineral classification system also including ternary or higher compounds is firstly subjected and experimentally validated. The experimental elaboration started from a small number of 29 compounds, from which already two suitable reaction systems are identified. For one of these reaction systems, orthorhombic calcium dizinc-bisphosphate dihydrate to calcium dizinc-bisphosphate monohydrate, the cycling stability is firstly proven on a mineral sample.
Lightweight constructions have in many ways advantages through efficient use of materials. By biomimetic approaches, new possibilities are offered in materials science. In a new approach, ...three-phase-foams, which contain chemically reactive nanomaterials, were combined with carbon nanotubes to further improve foam stability and microstructure. The foam was designed in such a way that an application in inorganic binders as well as a separate material after a chemical treatment is possible. This approach enables a high stability of the particle-stabilized inorganic foams without drain within 60 min and low densities up to 90 kg/m³. Additionally, due to a pozzolanic hardening, reaction products were built, which result in further stabilization of the pore structure. Implementation of carbon nanotubes causes not only smaller pore sizes but also smaller border or lamellae widths. Furthermore, they act as seeds for the formation of calcium–silicate–hydrates (C–S–H) phases or other strengthening reaction products. Investigations of the phase development and microstructure of the achieved carbon nanotube-stabilized foams will be shown and explained. Additionally, a first hypothesis about the interaction mechanism between the used nanoparticles, carbon nanotubes, and surfactant is described.
Thermochemical heat storage concepts offer a promising contribution to an economic, efficient and sustainable future energy supply. The reaction system CaO/Ca(OH)2 is amongst the most considered ...systems for Concentrated Solar Power (CSP) applications, but as the cost efficiency and good availability of the material are accompanied by poor powder properties, complex and costly reactor solutions are required. Hence, modifications of the storage material promise a option for a reliable long-term operation. The present work discusses considerations on inter- and intraparticular changes of the storage material and options for particle size stabilization. With the background of a previous work, the experimental section presents a successful approach for the enhancement of the mechanical stability of a ceramic shell material by admixing selected additives to the powdery precursor. To assign for possible complex, mutual interactions of the additives, the approach is based on a full factorial design of experiments. Investigations of the microstructure of the material are performed by gas-adsorption and mercury intrusion measurements and enriched by combining light- and scanning electron microscopy on respective samples. The obtained mechanical stability of the selected material is accompanied by a significantly enhanced thermal conductivity. Cycling stability is proven over ten reaction cycles in laboratory and reactor scale. Due to a minimization of the contact area between the storage material core and its stabilizing shell by utilizing spherical particles, it is demonstrated that only a minor formation of thermochemically inert side product is detectable.
Mangroves are recognized for their valued ecosystem services provision while having the highest carbon density among forested ecosystems. Yet they are increasingly threatened by deforestation, ...conversion to agriculture and development, reducing the benefits they provide for local livelihoods, coastal protection and climate change mitigation. Accordingly, accurate estimates of mangrove area and change are fundamental for developing strategies for sustainable use, conservation and Reducing Emissions from Deforestation and Degradation (REDD+). The Zambezi River Delta in Mozambique contains one of the largest mangrove forests in Africa, and deforestation has been reported to be substantial, however these estimates vary widely. We used Landsat imagery from 1994, 2000 and 2013, to estimate a total current mangrove area of 37,034 ha, which is a net increase of 3723 ha over 19 years. The land cover change assessment was also used to provide perspective on ecosystem carbon stocks, showing that the Zambezi Delta mangrove ecosystem acts as a large carbon sink. Our findings reinforce the importance of conducting land cover change assessments using coherent data and analytical models, coupled with field validation. Broader application of our approach could help quantify the rates of natural change from erosion and land aggradation contrasted with anthropogenic causes.
PDF