Two Physically Different Neutron Beta-Decay Half-Life Calculations are in Exact Agreement with the NIST Beam Experiment
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This paper presents two calculations of the free-neutron lifetime. The calculations reflect two distinct physical viewpoints, and both are in exact agreement with each other, and within reported significant figures, in exact agreement with the NIST Beam Experiment measurement of the neutron lifetime (887.7 (+/- 3.1) seconds (615.3 second half-life)). Both calculations are a priori requiring no arbitrary parameters. CODATA 2018 values used for physical constants. Currently the 'beam' method and the 'magnetic bottle/trap' method are the two primary experiments for determining neutron lifetime. Given the error bands, the results of the experiments are not in agreement. It is considered a significant objective to bring the measurements into agreement or provide a theoretical explanation of why they are different. This paper presents results of two calculations based on different physical origins.The half-life result of both calculations are in exact agreement with the 'beam' experiment.Keywords:
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Neutron-induced interactions contribute to the signal-mimicking background in deep-underground searches for exotic phenomena such as Dark Matter, neutrino-less double beta decay, proton decay, etc. Apart from radioactive decay, the primary source of neutrons underground are high-energy muons from cosmic showers. While the maximum number of fission neutrons is around six and energies around one MeV, muon-induced interactions may generate hundreds of neutrons, also with high energies. Furthermore, these processes are not yet reproduced in numerical simulations with sufficient reliability. The main goal of the NEMESIS experiment is to improve our knowledge and understanding of cosmic muon-induced neutron production in high-Z targets. NEMESIS (New Emma MEasurementS Including neutronS) is taking data at a depth of 210 m.w.e. in Callio Lab in the Pyhäsalmi mine, Finland.
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The development of atomic frequency standards at NIST is discussed and three of the key frequency-standard technologies of the current era are described.For each of these technologies, the most recent NIST implementation of the particular type of standard is described in greater detail.The best relative standard uncertainty achieved to date for a NIST frequency standard is 1.5ϫ10 -15 .The uncertainties of the most recent NIST standards are displayed relative to the uncertainties of atomic frequency standards of several other countries.
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Standard uncertainty
Frequency standard
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Assessing the Impact of the National Institute of Standards and Technology’s Research Collaborations
The Information Services Office (ISO) of the National Institute of Standards and Technology (NIST) conducted a study to assess the impact of NIST research collaborations by analyzing the NIST papers coauthored with other researchers external to NIST. This request from NIST senior management focused on the number of unique non-NIST coauthors on NIST-authored papers and the number of unique institutions and countries with which NIST collaborated on publications for the past five years. This article describes the methodology used to assess the impact of NIST’s publication collaborations and shares the results of ISO’s study.
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Представлены и обсуждаются результаты эмпирического тестирования возможности обнаружения длинных повторов в двоичных последовательностях набором статистических тестов NIST. Набор детерминированных двоичных последовательностей, которые не отклоняются пакетом NIST, искажается детерминированным образом. Для того чтобы повредить двоичную последовательность, выбирается несколько ее подстрок фиксированной длины и каждая подстрока дублируется в случайном месте последовательности. Длина повторяющихся подстрок была выбрана значительно большей типичной длины самой длинной повторяющейся подстроки. Если количество повторяющихся подстрок в поврежденной последовательности невелико, то пакет NIST не отклоняет такие неслучайные криптографически слабые двоичные последовательности. Описан алгоритм, реализующий поиск самого длинного повторения подстрок в двоичной последовательности длины $n$. Этот алгоритм основан на дереве суффиксов, и его временная и пространственная сложности имеют порядок $O(n)$.
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The NIST Office of Weights and Measures (OWM) presents its first report 2022 NIST Annual Summary of U.S. Legal Metrology Activities report. This report includes a summary of changes made to NIST Handbook 44 (2021) Specifications, Tolerances and Other Technical requirements for Commercial Weighing and Measuring Devices, NIST Handbook 130 (2021), Uniform Laws and Regulations in the Areas of Legal Metrology an Engine Fuel Quality, and NIST Handbook 133 (2020), Checking the Net Contents of Packaged Goods. The summary will provide an archival record of proposals and associated actions with the goal of assisting the weights and measures community in consistently interpreting and implementing NIST Handbooks 44, 130, and133. Included within each item in this report is an NIST OWM technical analysis, background information, and a summary of any actions taken on proposed changes to these NIST Handbooks considered in 2022
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The National Institute of Standards and Technology (NIST) is deploying disciplined oscillators that are referenced to the UTC(NIST) time scale through common-view observations of Global Positioning System (GPS) satellites. We present measurement results from four NIST disciplined oscillators (NISTDOs), three located in the United States, and one located in Concepcion, Chile. These devices replicate the NIST time scale at remote sites, and uncertainties of less than 5 ns are demonstrated at all locations. The results were verified by utilizing the national time scale of Mexico as an independent check standard. Further verification was obtained by directly comparing a NISTDO to UTC(NIST) in Boulder, Colorado.
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Replicate
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A method is demonstrated where by the use of the NIST (National Institute of Standards and Technology) reference material 8130 and NIST MultiCal® software allow the performance of modern performance network analyzers (PNA) to be evaluated and compared to a NIST benchmark TRL calibration. The analysis, presented here, is useful in the assessment of calibration repeatability. It also yields information to help improve the comparison of VNA measurement results from across various Intel laboratories.
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The equations developed for NIST (formerly National Bureau of Standards) thermal conductivity Standard Reference Materials (SRM's) were derived from thermal conductivity measurements made on guarded hot plate apparatuses at NIST. These instruments are briefly described in the certificates and more fully described in NIST special publications [1,2] Critical to the conclusions ofthis report is the size of the heat flow meter apparatus used for making measurements on the NIST thermal conductivity standards. This work describes additional variability in the NIST thermal conductivity standards when they are measured on a system which is smaller than the guarded hot plate apparatuses used at NIST
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Primary standard
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This paper focuses upon the uncertainty of force calibration measurements at the National Institute of Standards and Technology (NIST).The uncertainty of the realization of force for the national deadweight force standards at NIST is discussed, as well as the uncertainties associated with NIST's voltage-ratio measuring instruments and with the characteristics of transducers being calibrated.The combined uncertainty is related to the uncertainty of dissemination for force transfer standards sent to NIST for calibration.
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