We report on the light sterile neutrino search from the first four-week science run of the KATRIN experiment in 2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are ...analyzed by a high-resolution MAC-E filter down to 40 eV below the endpoint at 18.57 keV. We consider the framework with three active neutrinos and one sterile neutrino. The analysis is sensitive to the mass, m_{4}, of the fourth mass state for m_{4}^{2}≲1000 eV^{2} and to active-to-sterile neutrino mixing down to |U_{e4}|^{2}≳2×10^{-2}. No significant spectral distortion is observed and exclusion bounds on the sterile mass and mixing are reported. These new limits supersede the Mainz results for m_{4}^{2}≲1000 eV^{2} and improve the Troitsk bound for m_{4}^{2}<30 eV^{2}. The reactor and gallium anomalies are constrained for 100<Δm_{41}^{2}<1000 eV^{2}.
Radioactive sources of the monoenergetic low-energy conversion electrons from the decay of isomeric
83
m
Kr
are frequently used in the systematic measurements, particularly in the neutrino mass and ...dark matter experiments. For this purpose, the isomer is obtained by the decay of its parent radionuclide
83
Rb
. In order to get more precise data on the gamma-rays occuring in the
83
Rb
/
83
m
Kr
chain, we re-measured the relevant gamma-ray spectra, because the previous measurement took place in 1976. The obtained intensities are in fair agreement with the previous measurement. We have, however, improved the uncertainties by a factor of 4.3, identified a new gamma transition and determined more precisely energies of weaker gamma transitions.
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 cosmology.
Some extensions of the Standard Model of particle physics allow for Lorentz invariance and charge-parity-time invariance violations. In the neutrino sector strong constraints have been set by ...neutrino-oscillation and time-of-flight experiments. However, some Lorentz-invariance-violating parameters are not accessible via these probes. In this work, we focus on the parameters (a$^{(3)}_{of}$)00, (a$^{(3)}_{of}$)10, and (a$^{(3)}_{of}$)11 which would manifest themselves in a nonisotropic β-decaying source as a sidereal oscillation and an overall shift of the spectral endpoint. Based on the data of the first scientific run of the KATRIN experiment, we set the first 90% confidence-level limit on (a$^{(3)}_{of}$)11| of < 0.9 × 10–6 GeV to 3.7 × 10–6 GeV, depending on the phase. Furthermore, we derive new constraints on (a$^{(3)}_{of}$)00 and (a$^{(3)}_{of}$)10.
Aim
Neurofibromatosis type 1 (NF1) is a genetic disorder with a cognitive profile that includes visual–spatial perception deficits and a high incidence of reading disability. There is a paucity of ...information about how this cognitively complex population responds to mainstream reading interventions. The clinical trial goals were to determine whether children and adolescents with NF1 and reading deficits (NF+RD) benefit from mainstream remedial reading programs and whether responsiveness varies with differences in program‐related visual–spatial demands.
Method
Forty‐nine participants (28 males, 21 females; aged 8–14y) with either NF+RD (n=17, 11 males, six females) or idiopathic reading deficit (IRD) (n=32, 17 males, 15 females) were randomly assigned to intensive remedial teaching using one of two multisensory reading programs: one with greater kinesthetic demands and the other with greater visual–spatial demands. Two control groups – wait‐list IRD (n=14, 11 males, three females) and typically developing readers (n=26, 13 males, 13 females) – received no treatment. Repeated measures and multivariate ANOVA analyses compared each group's growth in reading achievement from pre‐ to post‐testing.
Results
Treated groups showed significant growth whereas untreated groups did not. Comparing treated groups, the IRD group responded equally well to both interventions, whereas the NF+RD group showed a better response to the more kinesthetic approach.
Interpretation
Results suggest that multisensory remedial reading teaching that emphasizes kinesthetic demands more than visual–spatial demands is suitable for students with NF+RD.
What this paper adds
Children with neurofibromatosis type 1 and reading deficits benefit from mainstream approaches to remedial reading instruction.
They may benefit more from multisensory instruction that does not emphasize visual–spatial discrimination.
A relevant short‐term learning task for testing efficacy of drug treatments for cognitive deficits in neurofibramotosis type 1.
This article is commented on by Acosta on pages 1088–1089 of this issue.
Radioactive sources of the monoenergetic low-energy conversion electrons from
the decay of isomeric $^{83m}Kr$ are frequently used in the systematic
measurements, particularly in the neutrino mass ...and dark matter experiments.
For this purpose, the isomer is obtained by the decay of its parent
radionuclide $^{83}Rb$. In order to get more precise data on the gamma-rays
occuring in the $^{83}Rb$/$^{83m}Kr$ chain, we re-measured the relevant
gamma-ray spectra, because the previous measurement took place in 1976. The
obtained intensities are in fair agreement with this previous measurement. We
have, however, improved the uncertainties by a factor of 4.3, identified a new
gamma transition and determined more precisely energies of weaker gamma
transitions.
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