Analysis methods for the first KATRIN neutrino-mass measurement

We report on the dataset, data handling, and detailed analysis techniques of the first neutrino-mass measurement by the Karlsruhe Tritium Neutrino (KATRIN) experiment, which probes the absolute neutrino-mass scale via the β-decay kinematics of molecular tritium. The source is highly pure, cryogenic T2 gas. The β electrons are guided along magnetic field lines toward a high-resolution, integrating spectrometer for energy analysis. A silicon detector counts β electrons above the energy threshold of the spectrometer, so that a scan of the thresholds produces a precise measurement of the high-energy spectral tail. After detailed theoretical studies, simulations, and commissioning measurements, extending from the molecular final-state distribution to inelastic scattering in the source to subtleties of the electromagnetic fields, our independent, blind analyses allow us to set an upper limit of 1.1 eV on the neutrino-mass scale at a 90% confidence level. This first result, based on a few weeks of running at a reduced source intensity and dominated by statistical uncertainty, improves on prior limits by nearly a factor of two. This result establishes an analysis framework for future KATRIN measurements, and provides important input to both particle theory and cosmolog

Suppression of Penning discharges between the KATRIN spectrometers

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMThe KArlsruhe TRItium Neutrino experiment (KATRIN) aims to determine the effective electron (anti)-neutrino mass with a sensitivity of 0.2eV/c2 by precisely measuring the endpoint region of the tritium β-decay spectrum. It uses a tandem of electrostatic spectrometers working as magnetic adiabatic collimation combined with an electrostatic (MAC-E) filters. In the space between the pre-spectrometer and the main spectrometer, creating a Penning trap is unavoidable when the superconducting magnet between the two spectrometers, biased at their respective nominal potentials, is energized. The electrons accumulated in this trap can lead to discharges, which create additional background electrons and endanger the spectrometer and detector section downstream. To counteract this problem, “electron catchers” were installed in the beamline inside the magnet bore between the two spectrometers. These catchers can be moved across the magnetic-flux tube and intercept on a sub-ms time scale the stored electrons along their magnetron motion paths. In this paper, we report on the design and the successful commissioning of the electron catchers and present results on their efficiency in reducing the experimental backgroun

First operation of the KATRIN experiment with tritium

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UA

Precision measurement of the electron energy-loss function in tritium and deuterium gas for the KATRIN experiment

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMThe KATRIN experiment is designed for a direct and model-independent determination of the effective electron anti-neutrino mass via a high-precision measurement of the tritium β-decay endpoint region with a sensitivity on mν of 0.2 eV /c 2 (90% CL). For this purpose, the β-electrons from a high-luminosity windowless gaseous tritium source traversing an electrostatic retarding spectrometer are counted to obtain an integral spectrum around the endpoint energy of 18.6 keV. A dominant systematic effect of the response of the experimental setup is the energy loss of β -electrons from elastic and inelastic scattering off tritium molecules within the source. We determined the energy-loss function in-situ with a pulsed angular-selective and monoenergetic photoelectron source at various tritium-source densities. The data was recorded in integral and differential modes; the latter was achieved by using a novel time-of-flight technique. We developed a semi-empirical parametrization for the energy-loss function for the scattering of 18.6-keV electrons from hydrogen isotopologs. This model was fit to measurement data with a 95% T 2 gas mixture at 30 K, as used in the first KATRIN neutrino-mass analyses, as well as a D 2 gas mixture of 96% purity used in KATRIN commissioning runs. The achieved precision on the energy-loss function has abated the corresponding uncertainty of σ(mν2) < 10-2eV2 [1] in the KATRIN neutrino-mass measurement to a subdominant leve

Improved eV-scale sterile-neutrino constraints from the second KATRIN measurement campaign

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMWe present the results of the light sterile neutrino search from the second Karlsruhe Tritium Neutrino (KATRIN) measurement campaign in 2019. Approaching nominal activity, 3.76 × 106 tritium β-electrons are analyzed in an energy window extending down to 40 eV below the tritium end point at E0 = 18.57 keV. We consider the 3ν + 1 framework with three active and one sterile neutrino flavors. The analysis is sensitive to a fourth mass eigenstate m42 ≲ 1600 eV2 and active-to-sterile mixing |Ue4|2 ≳ 6 × 10-3. As no sterile-neutrino signal was observed, we provide improved exclusion contours on m42 and |Ue4|2 at 95% C.L. Our results supersede the limits from the Mainz and Troitsk experiments. Furthermore, we are able to exclude the large Δm412 solutions of the reactor antineutrino and gallium anomalies to a great extent. The latter has recently been reaffirmed by the BEST Collaboration and could be explained by a sterile neutrino with large mixing. While the remaining solutions at small Δm412 are mostly excluded by short-baseline reactor experiments, KATRIN is the only ongoing laboratory experiment to be sensitive to relevant solutions at large Δm412 through a robust spectral shape analysi

New constraint on the local relic neutrino background overdensity with the first KATRIN data runs

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMWe report on the direct search for cosmic relic neutrinos using data acquired during the first two science campaigns of the KATRIN experiment in 2019. Beta-decay electrons from a high-purity molecular tritium gas source are analyzed by a high-resolution MAC-E filter around the end point at 18.57 keV. The analysis is sensitive to a local relic neutrino overdensity ratio of η < 9.7 × 1010/α (1.1 × 1011/α) at a 90% (95%) confidence level with α = 1 (0.5) for Majorana (Dirac) neutrinos. A fit of the integrated electron spectrum over a narrow interval around the end point accounting for relic neutrino captures in the tritium source reveals no significant overdensity. This work improves the results obtained by the previous neutrino mass experiments at Los Alamos and Troitsk. We furthermore update the projected final sensitivity of the KATRIN experiment to η < 1 × 1010/α at 90% confidence level, by relying on updated operational condition

Predictive model for cytoneme guidance in Hedgehog signaling based on Ihog- Glypicans interaction

Additional information Supplementary information The online version contains supplementary material available at https://doi.org/10.1038/s41467-022-33262-4.Acknowledgements We are grateful to and Pedro Ripoll and Ana-Citlali Gradilla for comments on the manuscript. We also thank to Laura González-Méndez, Carlos Jiménez-Jiménez, David Sánchez-Hernández and Eléanor Simon in I.G laboratory for their help with some experiments, the Confocal Facilities of the CBMSO and Bloomington and Vienna stock centers for fly stocks. This work was supported by grants BFU2017-83789-P, PID2020-114533GB-C21 and TENTACLES consortium RED2018-102411-T to I.G from the Spanish Ministry of Science, Innovation and Universities and by institutional grants from the Fundación Areces and Banco de Santander to the CBMSO. FPI fellowship from the Spanish Ministry of Science, Innovation and Universities supported A.A-T (BFU2017-83789- P). This work was also supported by grants RTI2018-098850-B-I00 to J.S from the MINECO-Feder (Spain), PY18-RT-2422 & A-FQM-311-UGR18 to M.C, D.P and J.S from the Junta de Andalucia (Spain), MECD (Spain) research grant FPI2015/074837 to M.C, and partially supported by the MECD (Spain) research grant FPU14/06304 and the European Research Council (Europe) Project ERC-COG-2019 WACONDY (grant agreement No 865711) to D.P.MINECO-Feder A-FQM-311-UGR18, PY18-RT-2422Banco Santander RTI2018-098850-B-I00Ministerio de Ciencia, Innovación y Universidades MCIUEuropean Research Council 865711, ERC-COG-2019 ERCMinisterio de Educación, Cultura y Deporte FPI2015/074837, FPU14/06304Junta de Andalucí

Implementing evidence-based practices on the therapeutic relationship in inpatient psychiatric care: a participatory action research

Aims and objectives: to produce changes in the therapeutic relationship between clinical practice nurses and patients in psychiatric units by implementing evidence-based practices through participatory action research. Background: the therapeutic relationship is the cornerstone of nursing care in psychiatric units. The literature suggests that theoretical knowledge alone is insufficient to establish the therapeutic relationship in practice. Therefore, strategies are needed to adequately establish the therapeutic relationship in psychiatric units. Design: participatory action research. Methods: participants consisted of nurses from two psychiatric units of a university hospital. Data were collected through focus groups and reflective diaries, which were analysed using the content analysis method. The COREQ guidelines were followed to ensure rigour. Results: nurses conceptualised the therapeutic relationship in their practice, identifying facilitating elements and limitations. They were able to compare their clinical practice with the recommendations of scientific evidence and constructed three evidence-based proposals to improve the therapeutic relationship: (a) a customised nurse intervention space, (b) knowledge updating and (c) reflective groups, which they subsequently implemented and evaluated. Conclusions: this study shows that nurses in psychiatric units can generate changes and improvements in the therapeutic relationship. The process of implementing evidence-based practice enhanced participants' awareness of their clinical practice and allowed them to make changes and improvements. Relevance to clinical practice: the process confirmed that the implementation of evidence-based practice through participatory methods, such as participatory action research, is valid and produces lasting changes. This study also reveals the need to rethink nurses' functions and competencies in current psychiatric units