Mainz Neutrino Mass Experiment Research Articles

Limit on sterile neutrino contribution from the Mainz Neutrino Mass Experiment

The recent analysis of the normalization of reactor antineutrino data, the calibration data of solar neutrino experiments using gallium targets, and the results from the neutrino oscillation experiment MiniBooNE suggest the existence of a fourth light neutrino mass state with a mass of O(eV), which contributes to the electron neutrino with a sizable mixing angle. Since we know from measurements of the width of the Z0 resonance that there are only three active neutrinos, a fourth neutrino should be sterile (i.e., interact only via gravity). The corresponding fourth neutrino mass state should be visible as an additional kink in beta-decay spectra. In this work the phase II data of the Mainz Neutrino Mass Experiment have been analyzed searching for a possible contribution of a fourth light neutrino mass state. No signature of such a fourth mass state has been found and limits on the mass and the mixing of this fourth mass states are derived.

An angular resolved pulsed UV LED photoelectron source for KATRIN

The KArlsruher TRItium Neutrino experiment KATRIN aims to determine the mass of the electron antineutrino with a sensitivity of 0.2 eV/c 2 on m ( ν e ) at 90% confidence level by measuring the kinematics of the tritium beta decay with a spectrometer of MAC-E filter-type. To investigate the properties of the spectrometer, electron sources with special properties are needed. A pulsed UV LED photoelectron source with angular selectivity has been developed for this purpose. The principle has been successfully tested during measurements at the spectrometer of the Mainz neutrino mass experiment.

The Mainz Neutrino Mass Experiment

Abstract The Mainz neutrino mass experiment is investigating the endpoint region of the tritium β decay spectrum to determine the mass of the electron antineutrino. With its recently improved setup data were taken over more than 7 month in 1998 and 1999. For these measurements two different analyses are presented leading to mv2 = +0.6±2.8±2.1 eV2/c4and mv2 = −1.6 ± 2.5 ± 2.1 eV2/c4, from which upper limits of mv

Latest results of the Mainz Neutrino Mass Experimen

The Mainz Neutrino Mass Experiment investigates the endpoint region of the tritium β decay spectrum very precisely to extract the rest mass of the electron antineutrino. The measurements are performed with a MAC-E-Filter, combining agnetic diabatic ollimation and an lectrostatic high pass Filter. After optimal preparation of the apparatus very stable and high quality data have been taken in 2001, which do not show any residual problem. A combined analysis of data from 1998/1999 and 2001 lead to the final value of m ν 2 = –0.7 ± 2.2 stat ± 2.1 sys eV2/c4, leading to an upper limit m ν ≤ 2.3 eV/c2 (95% C.L.). PACS: 14.60.P Neutrinos, mass and mixing – 23.40 β decay

Latest results from the Mainz Neutrino Mass experiment

The Mainz Neutrino Mass experiment investigates the endpoint region of tritium β decay spectrum very precisely to extract the rest mass of the electron antineutrino. The measurements are performed with a MAC-E-Filyer, combining M agnetic A diabatic C ollimation and an E lectrostatic high pass Filter. After an optimal preparation very stable and high quality data have been taken in 2001, which do not show any residual problem.

Most recent results of the Mainz neutrino mass experiment

Most recent results of the Mainz neutrino mass experiment

Results from the mainz neutrino mass experiment

The presently lowest limit for the mass of the electron neutrino is m ν<2.2 eV/c 2 95% C.L.) derived from measurements at Mainz up to 1999. The data taken in 2000 are not fully analyzed yet, but limits of possible distortions as reported by the Troitsk group can be given.

Results from the Mainz neutrino mass experiment

The presently lowest limit for the mass of the electron neutrino is m ν < 2.2 eV/c 2 (95 %C.L.) derived from measurements at Mainz up to 1999. The data taken in 2000 are not fully analyzed yet but limits of possible distortions as reported by the Troitsk group can be given.

The Mainz neutrino mass experiment

The Mainz neutrino mass experiment is investigating the endpoint region of the tritium β decay spectrum to determine the mass of the electron antineutrino. With its recently improved setup data were taken over more than 7 month in 1998 and 1999. For these measurements two different analyses are presented leading to m v 2 = +0.6±2.8±2.1 eV 2/c 4and m v 2 = −1.6 ± 2.5 ± 2.1 eV 2/c 4, from which upper limits of m v < 2.8 eV/c 2 (95 % C. L.) and m v < 2.2 eV/c 2 (95 % C.L.) are derived. Only in one of six data sets was a clear indication for the anomaly, reported by the Troitsk group, found, and its postulated half year period is contradicted by our data. To push the sensitivity on the neutrino mass below 1 eV/c 2 a new larger MAC-E spectrometer is proposed. Besides its integrating mode it could operate in a new non-integrating MAC-E-TOF mode.

On dewetting dynamics of solid films of hydrogen isotopes and its influence on tritium spectroscopy

The dewetting dynamics of solid films of hydrogen isotopes, quench-condensed on a graphite substrate, was measured at various temperatures below desorption by observing the stray light from the film. A schematic model describing the dewetting process by surface diffusion is presented, which agrees qualitatively with our data. The activation energies of different hydrogen isotopes for surface diffusion were determined. The time constant for dewetting of a quench-condensed T2 film at the working temperature of 1.86 K of the mainz neutrino mass experiment was extrapolated.

Results of the Mainz neutrino mass experiment

The Mainz neutrino mass experiment investigates the endpoint region of the tritium β decay spectrum to determine the mass of the electron antineutrino. By the recent upgrade the former problem of dewetting T 2 films has been solved and the signal-to-background-ratio was improved by a factor of 10. The latest measurement leads to m ν 2 = −1.1 ± 2.6 stat ± 1.8 sys eV 2 c 4 (priliminary), which corresponds to an upper limit of m ν < 2.3 eV c 2 (95 % C.L.) (preliminary). Some indication for the anomaly, reported by the Troitsk group, was found, but its postulated half year period is contradicted by our data.

Newest results from the Mainz neutrino-mass experiment

Newest results from the Mainz neutrino-mass experiment

Newest results from the Mainz neutrino mass experiment

The Mainz neutrino mass experiment investigates the endpoint region of the tritium β decay spectrum with a MAC-E spectrometer to determine the mass of the electron antineutrino. By the recent upgrade the former problem of dewetting T 2 films has been solved and the signal-to-background-ratio was improved by a factor of 10. The latest measurement leads to m v 2 = −3.7 ± 5.3 stat ± 2.1 sys eV 2/c 4, from which an upper limit of m v < 2.8 eV/c 2 (95 % C.L.) is derived. Some indication for the anomally, reported by the Troitsk group, was found, but its postulated half year period is contradicted by our data. To push the sensitivity on the neutrino mass below 1 eV/c 2 a new larger MAC-E spectrometer is proposed. Besides its integrating mode it could run in a new non-integrating operation MAC-E-TOF mode.

High precision measurement of the tritium β spectrum near its endpoint and upper limit on the neutrino mass

The Mainz neutrino mass experiment investigates the endpoint region of the tritium β decay spectrum to determine the mass of the electron antineutrino. By the recent upgrade the former problem of dewetting T 2 films has been solved and the signal-to-background-ratio was improved by a factor of 10. The latest measurement leads to m ν 2=−3.7±5.3 stat ±2.1 sys eV 2/c 4 , from which an upper limit of m ν<2.8 eV/c 2 (95% C.L.) is derived. Some indication for the anomaly, reported by the Troitsk group, was found, but its postulated half year period is contradicted by our data.

New results from the mainz neutrino mass experiment

The present status of the Mainz tritium β decay experiments is given. The very recent improvement of the Mainz setup and the first results from tritium data are presented. The former trend towards negative values of m ν 2 for increasing data intervals was identified to be a roughening transition of the quench-condensed T 2 film, which now can be avoided.

New results from the Mainz neutrino mass experiment

The present status of the Mainz tritium β decay experiments is given. The very recent improvement of the Mainz setup and the first results from tritium data are presented. The former trend towards negative values of m ν 2 for increasing data intervals was identified to be a roughening transition of the quench-condensed T 2 film, which now can be avoided.

Status and perspectives of the Mainz neutrino mass experiment

The Mainz measurement in 1994 is discussed in the view of the problem of “negative m ν 2” obtained in the analysis for larger energy intervals below the endpoint of the β spectrum. A possible explanation due to a roughening transition of the T 2 film is given. The very recent improvement of the Mainz setup and a first 4 weeks measurement is presented. An outlook to the perspectives of the present setup and into the future is given.