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Since the discovery of neutrino oscillations, we know that neutrinos have non-zero mass. However, the absolute neutrino-mass scale remains unknown. Here we report the upper limits on effective electron anti-neutrino mass, m ν , from the second physics run of the Karlsruhe Tritium Neutrino experiment. In this experiment, m ν is probed via a high-precision measurement of the tritium β -decay spectrum close to its endpoint. This method is independent of any cosmological model and does not rely on assumptions whether the neutrino is a Dirac or Majorana particle. By increasing the source activity and reducing the background with respect to the first physics campaign, we reached a sensitivity on m ν of 0.7 eV  c –2  at a 90% confidence level (CL). The best fit to the spectral data yields m ν 2  = (0.26 ± 0.34) eV 2   c –4 , resulting in an upper limit of m ν  < 0.9 eV  c –2  at 90% CL. By combining this result with the first neutrino-mass campaign, we find an upper limit of m ν  < 0.8 eV  c –2 at 90% CL. In its second measurement campaign, the Karlsruhe Tritium Neutrino experiment achieved a sub-electronvolt sensitivity on the effective electron anti-neutrino mass.

The projected sensitivity of the effective electron neutrino-mass measurement with the KATRIN experiment is below 0.3 eV (90 % CL) after 5 years of data acquisition. The sensitivity is affected by the increased rate of the background electrons from KATRIN’s main spectrometer. A special shifted-analysing-plane (SAP) configuration was developed to reduce this background by a factor of two. The complex layout of electromagnetic fields in the SAP configuration requires a robust method of estimating these fields. We present in this paper a dedicated calibration measurement of the fields using conversion electrons of gaseous 83m Kr, which enables the neutrino-mass measurements in the SAP configuration.

Precision spectroscopy of the electron spectrum of the tritium β -decay near the kinematic endpoint is a direct method to determine the effective electron antineutrino mass. The KArlsruhe TRItium Neutrino (KATRIN) experiment aims to determine this quantity with a sensitivity of better than 0.3 eV ( 90 %  C.L.). An inhomogeneous electric potential in the tritium source of KATRIN can lead to distortions of the β -spectrum, which directly impact the neutrino-mass observable. This effect can be quantified through precision spectroscopy of the conversion-electrons of co-circulated metastable 83 m Kr . Therefore, dedicated, several-weeks long measurement campaigns have been performed within the KATRIN data taking schedule. In this work, we infer the tritium source potential observables from these measurements, and present their implications for the neutrino-mass determination.

One hundred and ninety-five participants in the Cincinnati Lead Study were neuropsychologically evaluated in mid-adolescence. The neuropsychological measures yielded five factors labeled Memory, Learning/IQ, Attention, Visuoconstruction, and Fine-Motor. Prenatal, Average Childhood, and 78 month blood lead (PbB) levels were used in a series of multiple regression analyses. Following rigorous covariate pretesting and adjustment, a significant main effect of 78 month PbB on the Fine-Motor factor was found (p < .004). Significant interactions were also found between gender and lead exposure parameters for both Attention and Visuoconstruction indicating heightened risk in males. Finally, a trend toward significance was found for the PbB × SES interaction for Learning/IQ, consistent with previous evidence of increased educational and cognitive vulnerability for youth from more disadvantaged backgrounds. These results provide new evidence from the longest continuing prospective study of the remote effects of early lead exposure. They indicate the presence of selective neuropsychological effects in this population, and also that males and females are not uniformly affected. These results also underscore the complexity of models of neurobehavioral development, and the modest predictive power of any single determinant. (JINS, 2004, 10, 261–270.)

Precision spectroscopy of the electron spectrum of the tritium$$\\upbeta $$β -decay near the kinematic endpoint is a direct method to determine the effective electron antineutrino mass. The KArlsruhe TRItium Neutrino (KATRIN) experiment aims to determine this quantity with a sensitivity of better than$${0.3}{\\hbox { eV}}$$0.3 eV ($$90\\%$$90 %  C.L.). An inhomogeneous electric potential in the tritium source of KATRIN can lead to distortions of the$$\\upbeta $$β -spectrum, which directly impact the neutrino-mass observable. This effect can be quantified through precision spectroscopy of the conversion-electrons of co-circulated metastable$$^{83\\text {m}}\\text {Kr}$$83 m Kr . Therefore, dedicated, several-weeks long measurement campaigns have been performed within the KATRIN data taking schedule. In this work, we infer the tritium source potential observables from these measurements, and present their implications for the neutrino-mass determination.

Precision spectroscopy of the electron spectrum of the tritium β-decay near the kinematic endpoint is a direct method to determine the effective electron antineutrino mass. The KArlsruhe TRItium Neutrino (KATRIN) experiment aims to determine this quantity with a sensitivity of better than 0.3 eV (90% C.L.). An inhomogeneous electric potential in the tritium source of KATRIN can lead to distortions of the β-spectrum, which directly impact the neutrino-mass observable. This effect can be quantified through precision spectroscopy of the conversion-electrons of co-circulated metastable 83mKr. Therefore, dedicated, several-weeks long measurement campaigns have been performed within the KATRIN data taking schedule. In this work, we infer the tritium source potential observables from these measurements, and present their implications for the neutrino-mass determination.

AbstractThe 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 [InlineMediaObject not available: see fulltext.]agnetic [InlineMediaObject not available: see fulltext.]diabatic [InlineMediaObject not available: see fulltext.]ollimation and an [InlineMediaObject not available: see fulltext.]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 mν2 = –0.7 ± 2.2stat ± 2.1sys eV2/c4, leading to an upper limit mν ≤ 2.3 eV/c2 (95% C.L.).PACS: 14.60.P Neutrinos, mass and mixing – 23.40 β decay

The projected sensitivity of the effective electron neutrino-mass measurement with the KATRIN experiment is below 0.3 eV (90 % CL) after 5 years of data acquisition. The sensitivity is affected by the increased rate of the background electrons from KATRIN’s main spectrometer. A special shifted-analysing-plane (SAP) configuration was developed to reduce this background by a factor of two. The complex layout of electromagnetic fields in the SAP configuration requires a robust method of estimating these fields. We present in this paper a dedicated calibration measurement of the fields using conversion electrons of gaseous 83mKr, which enables the neutrino-mass measurements in the SAP configuration.

Background: The Breast Cancer and the Environment Research Centers (BCERCs) include collaborators from basic sciences, epidemiology, and the community, conducting studies to investigate whether environmental exposures are associated with the timing of puberty. A pilot study of a subset of the study participants assessed the feasibility of measuring selected biomarkers of exposure in blood and urine in girls 6-8 years of age. In the Greater Cincinnati study population, we found an elevated serum concentration of perfluorooctanoate (PFOA) among > 90% of young girls living in a small community. Objectives: The research team deliberated whether and how to report the PFOA findings to our study families. We will address the issues considered in our decision, as well as the formats we used to present the findings. Methods: The results were verified as we searched for potential sources of the elevated PFOA levels. As a research team, we grappled with issues regarding the reporting of unexpected results, derived from unknown sources and with unknown clinical significance. Ultimately, we did decide to present these findings to the study families through a well-developed communication plan. Discussion: Research team members came from a variety of experiences and backgrounds, which led to different interpretations about the clinical, ethical, and public health issues surrounding these findings. The ethical debates centered around the precautionary principle, the right to know, and do no harm. Conclusions: Given advances in environmental biomarker technologies and greater use of the transdisciplinary research model, a communication plan must be developed for those involved as study participants.

In this work we present a keV-scale sterile-neutrino search with a low-tritium-activity data set of the KATRIN experiment, acquired in a commissioning run in 2018. KATRIN performs a spectroscopic measurement of the tritium β-decay spectrum with the main goal of directly determining the effective electron anti-neutrino mass. During this commissioning phase a lower tritium activity facilitated the measurement of a wider part of the tritium spectrum and thus the search for sterile neutrinos with a mass of up to 1.6 keV. We do not find a signal and set an exclusion limit on the sterile-to-active mixing amplitude of $\\text {sin}^{2}\\: \\theta<5\\times 10^{-4}\\: (95\\%\\: $C.L) at a mass of 0.3 keV. This result improves current laboratory-based bounds in the sterile-neutrino mass range between 0.1 and 1.0 keV.