1,333 research outputs found
Direct neutrino-mass measurement based on 259 days of KATRIN data
No full textThat neutrinos carry a nonvanishing rest mass is evidence of physics beyond the Standard Model of elementary particles. Their absolute mass holds relevance in fields from particle physics to cosmology. We report on the search for the effective electron antineutrino mass with the KATRIN experiment. KATRIN performs precision spectroscopy of the tritium β-decay close to the kinematic endpoint. On the basis of the first five measurement campaigns, we derived a best-fit value of mv2 = 0.14-0.15+0.13 eV2, resulting in an upper limit of mv < 0.45 eV at 90% confidence level. Stemming from 36 million electrons collected in 259 measurement days, a substantial reduction of the background level, and improved systematic uncertainties, this result tightens KATRIN’s previous bound by a factor of almost two
Search for keV-scale sterile Neutrinos with the first Light of KATRIN
No full textA sterile neutrino with a mass up to 18.6 keV would be visible in the beta-decay spectrum of tritium. The KATRIN experiment is designed to determine the absolute neutrinos mass by measuring the beta-decay spectrum of gaseous tritium close to its endpoint. Beyond that, it’s unprecedented tritium source luminosity and spectroscopic quality could be used to measure the entire beta-spectrum to search for a sterile neutrino. The idea presented on this poster is the so-called Phase-0 measurement, where the first light data of KATRIN would be used to scan the entire tritium beta-decay spectrum to search for sterile neutrinos. A measurement of only one week with KATRIN has the potential to improve the current laboratory limits for keV-scale sterile neutrinos. This work presents the expected sensitivity, important systematic effects and the experimental realization of this measurement. This work was supported by GRK1694, BMBF (05A17VK2), KSETA, the HGF and the Friedrich-Ebert-Stiftung
Analysis of first KATRIN data and searches for keV-scale sterile neutrinos
No full textThe phenomenon of neutrino oscillation stands in contradiction with the Standard Model of Particle Physics (SM) where neutrinos are formulated as massless particles. One way to introduce a non-zero neutrino mass to the SM is the so-called see-saw-mechanism. It adds at least one sterile neutrino to the particle framework. A sterile neutrino would not participate in any SM interaction, only interact gravitationally and would be of arbitrary mass-scale. These unique properties make a sterile neutrino an interesting Dark Matter candidate.
The Karlsruhe Tritium Neutrino (KATRIN) experiment aims to determine the effective electron anti-neutrino mass with a sensitvity of (90 C.L.) by observing the tritium -decay close to its kinematic endpoint. Studies show that the experiment can be additionally extended to search for a sterile neutrino, for example on the keV mass-scale.
This thesis specifies how the KATRIN experiment can be operated to search for keV-scale sterile neutrinos without any significant hardware modifications. It presents a first comprehensive overview of all yet known systematic effects that occur in such a measurement. This information is used for a first keV-scale sterile neutrino measurement with KATRIN data.
By analyzing 82 KATRIN -spectrum scans wit a total measurement time of approximately 160 hours, the current laboratory limit on the active-to-sterile mixing angle could be improved by up to a factor of eight on a mass scale of with a resolution on the mixing amplitude of up to
KATRIN: Status and Prospects for the Neutrino Mass and Beyond
No full textThe Karlsruhe Tritium Neutrino (KATRIN) experiment is designed to measure a
high-precision integral spectrum of the endpoint region of T2 beta decay, with
the primary goal of probing the absolute mass scale of the neutrino. After a
first tritium commissioning campaign in 2018, the experiment has been regularly
running since 2019, and in its first two measurement campaigns has already
achieved a sub-eV sensitivity. After 1000 days of data-taking, KATRIN's design
sensitivity is 0.2 eV at the 90% confidence level. In this white paper we
describe the current status of KATRIN; explore prospects for measuring the
neutrino mass and other physics observables, including sterile neutrinos and
other beyond-Standard-Model hypotheses; and discuss research-and-development
projects that may further improve the KATRIN sensitivity.Comment: Contribution to Snowmass 2021. 70 pages excluding references; 35
figures. Author list updated June 202
Hunting keV sterile neutrinos with KATRIN: Building the first TRISTAN module
No full textThe KATRIN (Karlsruhe Tritium Neutrino) experiment investigates the energetic endpoint of the tritium beta-decay spectrum to determine the effective mass of the electron anti-neutrino. The collaboration has reported a first mass measurement result at this TAUP-2019 conference. The TRISTAN project aims at detecting a keV-sterile neutrino signature by measuring the entire tritium beta-decay spectrum with an upgraded KATRIN system. One of the greatest challenges is to handle the high signal rates generated by the strong activity of the KATRIN tritium source while maintaining a good energy resolution. Therefore, a novel multi-pixel silicon drift detector and read-out system are being designed to handle rates of about 100 Mcps with an energy resolution better than 300 eV (FWHM). This report presents succinctly the KATRIN experiment, the TRISTAN project, then the results of the first 7-pixels prototype measurement campaign and finally describes the construction of the first TRISTAN module composed of 166 SDD-pixels as well as its implementation in KATRIN experiment
High-resolution spectroscopy of gaseous 83m Kr conversion electrons with the KATRIN experiment
No full text© 2020 The Author(s). Published by IOP Publishing Ltd. In this work, we present the first spectroscopic measurements of conversion electrons originating from the decay of metastable gaseous 83mKr with the Karlsruhe Tritium Neutrino (KATRIN) experiment. The obtained results represent one of the major commissioning milestones for the subsequent direct neutrino mass measurement with KATRIN. The successful campaign demonstrates the functionalities of the KATRIN beamline. Precise measurement of the narrow K-32, L3-32, and N2,3-32 conversion electron lines allowed to verify the eV-scale energy resolution of the KATRIN main spectrometer necessary for competitive measurement of the absolute neutrino mass scale
Comparing timing models of two Swiss German dialects
No full textResearch on dialectal varieties was for a long time concentrated on phonetic aspects of language. While there was a lot of work done on segmental aspects, suprasegmentals remained unexploited until the last few years, despite the fact that prosody was remarked as a salient aspect of dialectal variants by linguists and by naive speakers. Actual research on dialectal prosody in the German speaking area often deals with discourse analytic methods, correlating intonations curves with communicative functions (P. Auer et al. 2000, P. Gilles & R. Schrambke 2000, R. Kehrein & S. Rabanus 2001). The project I present here has another focus. It looks at general prosodic aspects, abstracted from actual situations. These global structures are modelled and integrated in a speech synthesis system. Today, mostly intonation is being investigated. However, rhythm, the temporal organisation of speech, is not a core of actual research on prosody. But there is evidence that temporal organisation is one of the main structuring elements of speech (B. Zellner 1998, B. Zellner Keller 2002). Following this approach developed for speech synthesis, I will present the modelling of the timing of two Swiss German dialects (Bernese and Zurich dialect) that are considered quite different on the prosodic level. These models are part of the project on the "development of basic knowledge for research on Swiss German prosody by means of speech synthesis modelling" founded by the Swiss National Science Foundation
High-resolution spectroscopy of gaseous 83m Kr conversion electrons with the KATRIN experiment
No full text© 2020 The Author(s). Published by IOP Publishing Ltd. In this work, we present the first spectroscopic measurements of conversion electrons originating from the decay of metastable gaseous 83mKr with the Karlsruhe Tritium Neutrino (KATRIN) experiment. The obtained results represent one of the major commissioning milestones for the subsequent direct neutrino mass measurement with KATRIN. The successful campaign demonstrates the functionalities of the KATRIN beamline. Precise measurement of the narrow K-32, L3-32, and N2,3-32 conversion electron lines allowed to verify the eV-scale energy resolution of the KATRIN main spectrometer necessary for competitive measurement of the absolute neutrino mass scale
All the birds are still here? : a didactic discussion about nature conservation issues in biology with a focus on ornithological topics
No full textDie Schule als Ort der Wissensvermittlung und der sozialen Interaktion ermöglicht es Kindern und Jugendlichen sich ein grundlegendes Wissen in verschiedenen Fächern anzueignen. Dabei wird dem Naturschutz, der in Österreich als Unterrichtsprinzip in allen Fächern behandelt werden soll, eine wichtige Rolle zuteil. Nur wenn die Schülerinnen und Schüler mit diesem Thema konfrontiert werden und wenn sie selbst einen emotionalen Bezug zu gefährdeten Arten aufbauen können, werden sie auch als Erwachsene verantwortungsbewusst und schonend mit der Na-tur und diversen Lebewesen umgehen.Um ein Basiswissen (auch für Lehrpersonen) etablieren zu können, werden im Theorieteil neben rechtlichen Grundlagen zum Natur- und Artenschutz sowie Lehrplaninhalten auch grundlegende Informationen zur Ornithologie geliefert. Der erklärte Fokus der vorliegenden Arbeit liegt jedoch auf der Vermittlung von Anliegen des Vogelschutzes und wie diese im Regelunterricht in Biologie und Umweltkunde Platz finden können.Schools as places of knowledge transfer and social interaction enable children and adolescents to acquire a basic knowledge in different subjects. Nature conservation which in Austria should be treated as a teaching principle in all subjects is a crucial theme. Only when students are confronted with this topic they are autonomously able to build an emotional connection to endangered species. Hence, as adults, it is very likely that they will also act responsibly and environmentally friendly regarding nature and various living beings.In order to be able to establish a basic level of knowledge (both for teachers and pupils), the theory chapters provide general information on ornithology in addition to legal regulations of nature and species protection as well as syllabus contents. However, the main focus of this thesis is to communicate concerns of bird protection and how they can be developed in biological and environmental education.vorgelegt von Katrin Alexandra Huber, BScZusammenfassungen in Deutsch und EnglischAbweichender Titel laut Übersetzung des Verfassers/der VerfasserinDiplomarbeit Karl-Franzens-Universität Graz 2019 241
Effectiveness of One-Euro-Jobs: Do programme characteristics matter?
No full text"Recent labour market reforms in Germany introduced a workfare programme called One-Euro-Jobs with roughly 700,000 means-tested benefit recipients participating per year. In programme design leeway is given to local actors to respond to regional and individual factors. The legislature has set only key features of One-Euro-Jobs: One-Euro-Jobs are required to be additional and temporary jobs of public interest. Using administrative data for participants who entered the programme in spring 2005 this paper investigates medium-term effects of the programme and the association between flexibility in design and effect heterogeneity. First, effects of different types of One-Euro-Jobs (according to planned duration and weekly working hours) compared to non-participation ('waiting') are estimated and second, programme types are compared directly by pairwise matching to disentangle selection and programme effects. As expected lock-in effects are larger for participation with a longer planned duration, whereas this is not the case for more intensive programmes in terms of working hours. In the medium term, One-Euro-Jobs do not generally increase the employment prospects for men in East Germany beyond two years after programme start and longer and more intensive participations even decrease employment prospects. In West Germany, One-Euro-Jobs in general increase the employment chances and longer participations lead to slightly higher employment opportunities roughly two years after programme start. The initial advantages of short participations decrease over time. " (Author's abstract, IAB-Doku) ((en))Arbeitsgelegenheit - Erfolgskontrolle, berufliche Reintegration, Arbeitslosengeld II-Empfänger, Workfare, Arbeitsmarktchancen, Geschlechterverteilung, Westdeutschland, Ostdeutschland, Bundesrepublik Deutschland
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