The Search for Neutrino Oscillations numubar->nuebar with KARMEN

The neutrino experiment KARMEN is situated at the beam stop neutrino source ISIS. It provides numu's, nue's and numubar's in equal intensities from the pi+ mu+ decay at rest (DAR). The oscillation channel numub->nueb is investigated in the appearance mode with a 56t liquid scintillation calorimeter at a mean distance of 17.7m from the nu source looking for p(nue,e+)n reactions. The cosmic induced background for this oscillation search could be reduced by a factor of 40 due to an additional veto counter installed in 1996. In the data collected through 1997 and 1998 no potential oscillation event was observed. Using a unified approach to small signals this leads to an upper limit for the mixing angle of sin**2(2t) < 1.3x10^{-3} (90%CL) at large Dm**2. The excluded area in (sin**2(2t),Dm**2) covers almost entirely the favored region defined by the LSND numub->nueb evidence.Comment: Proceedings Contribution to Neutrino98 in Takayama, Japan, June 4-9, 1998; 13 pages, including 4 figure

Doing Interventions : Experiments and Collaborations in Contemporary Ethnography

In dieser Einleitung zur 83. Ausgabe der Kulturanthropologie Notizen stellen wir das Konzept der Intervention ins Zentrum und betonen wie Forscher:innen und ihre Felder immer aufeinander bezogen sind. Während wir grundsätzlich davon ausgehen, dass ethnographische Studien per se als interventionistisch verstanden werden können, diskutieren wir ‚doing interventions‘ als einen spezifischen, ethnographischen methodischen Ansatz und reflektieren insbesondere Experimente und Kollaborationen sowie deren epistemischen Effekte. In diesem Sinne verweisen Interventionen mit/in der Ethnographie auf ethnographisches Wissen, das einen Effekt auf das Feld hat, während die Praxis des Intervenierens zugleich auch die ethnographische Wissensproduktion verändern kann. Die Autor:innen dieser Ausgabe der Kulturanthropologie Notizen zeigen anhand einer Vielzahl von Beispielen, wie sich Interventionen mit und in der Ethnographie in der Praxis ausgestalten lassen und wie diese Modi miteinander verflochten sind. Die Fallstudien reichen von ethnografischer Forschung im globalen Lebensmittelsektor und in der Rohstoffindustrie über Feldforschung in und mit der Sozialpsychiatrie bis hin zu neuen Formen der Zusammenarbeit während der COVID-19-Pandemie. Nicht zuletzt wird die Anthropologie als Veränderungswissenschaft diskutiert. Was die Texte eint, ist die Überzeugung, dass Interventionen mit/in der Ethnographie das Potential haben Etabliertes und Selbstverständliches in Frage zu stellen, normative und dominante Wahrnehmungen der Wissensproduktion zu transformieren, Diskurse zu irritieren und gleichzeitig die Re-Imagination und Re-Konzeptualisierung der ethnographischen Praxis  zu fördern

Sensitivity to the KARMEN Timing Anomaly at MiniBooNE

We present sensitivities for the MiniBooNE experiment to a rare exotic pion decay producing a massive particle, Q^0. This type of decay represents one possible explanation for the timing anomaly reported by the KARMEN collaboration. MiniBooNE will be able to explore an area of the KARMEN signal that has not yet been investigated

β\beta-Decay Spectrum, Response Function and Statistical Model for Neutrino Mass Measurements with the KATRIN Experiment

The objective of the Karlsruhe Tritium Neutrino (KATRIN) experiment is to determine the effective electron neutrino mass $m(\nu_\text{e})$ with an unprecedented sensitivity of $0.2\,\text{eV}$ (90\% C.L.) by precision electron spectroscopy close to the endpoint of the $\beta$ decay of tritium. We present a consistent theoretical description of the $\beta$ electron energy spectrum in the endpoint region, an accurate model of the apparatus response function, and the statistical approaches suited to interpret and analyze tritium $\beta$ decay data observed with KATRIN with the envisaged precision. In addition to providing detailed analytical expressions for all formulae used in the presented model framework with the necessary detail of derivation, we discuss and quantify the impact of theoretical and experimental corrections on the measured $m(\nu_\text{e})$. Finally, we outline the statistical methods for parameter inference and the construction of confidence intervals that are appropriate for a neutrino mass measurement with KATRIN. In this context, we briefly discuss the choice of the $\beta$ energy analysis interval and the distribution of measuring time within that range.Comment: 27 pages, 22 figures, 2 table

Observables sensitive to absolute neutrino masses: A reappraisal after WMAP-3y and first MINOS results

In the light of recent neutrino oscillation and non-oscillation data, we revisit the phenomenological constraints applicable to three observables sensitive to absolute neutrino masses: The effective neutrino mass in single beta decay (m_beta); the effective Majorana neutrino mass in neutrinoless double beta decay (m_2beta); and the sum of neutrino masses in cosmology (Sigma). In particular, we include the constraints coming from the first Main Injector Neutrino Oscillation Search (MINOS) data and from the Wilkinson Microwave Anisotropy Probe (WMAP) three-year (3y) data, as well as other relevant cosmological data and priors. We find that the largest neutrino squared mass difference is determined with a 15% accuracy (at 2-sigma) after adding MINOS to world data. We also find upper bounds on the sum of neutrino masses Sigma ranging from ~2 eV (WMAP-3y data only) to ~0.2 eV (all cosmological data) at 2-sigma, in agreement with previous studies. In addition, we discuss the connection of such bounds with those placed on the matter power spectrum normalization parameter sigma_8. We show how the partial degeneracy between Sigma and sigma_8 in WMAP-3y data is broken by adding further cosmological data, and how the overall preference of such data for relatively high values of sigma_8 pushes the upper bound of Sigma in the sub-eV range. Finally, for various combination of data sets, we revisit the (in)compatibility between current Sigma and m_2beta constraints (and claims), and derive quantitative predictions for future single and double beta decay experiments.Comment: 18 pages, including 7 figure