Search results for "systematic error"
showing 10 items of 52 documents
Determination of the LEP centre-of-mass energy from Zγ events
1999
Radiative returns to the Z resonance (Zgamma events) are used to determine the LEP2 centre-of-mass energy from the data collected with the ALEPH detector in 1997. The average centre-of-mass energy is measured to be: E_CM = 182.50 +- 0.19(stat) +- 0.08(syst) GeV in good agreement with the precise determination by the LEP energy working group of 182.652 +- 0.050 GeV. If applied to the measurement of the W mass, its precision translates into a systematic error on M_W which is smaller than the statistical error achieved from the corresponding dataset.
Neutrino oscillation parameters: Future
2019
The Neutrino Oscillation Workshop (NOW2018) included a session addressing neutrino oscillation parameters in the future. This session included discussion of planned and proposed experiments, detector technologies, and analysis techniques to better measure neutrino oscillation parameters. Constraint of systematic uncertainty in future precision measurements was a topic of particular interest. This proceedings is a brief summary of the presentations in the Oscillation Parameters: Future session; readers are directed to individual contributions to the proceedings for more detailed information.
Evaluation of the MOD16A2 evapotranspiration product in an agricultural area of Argentina, the Pampas region
2021
The Pampas Region is a big plain of approximately 520,000 km2 in Argentina. It is essential to estimate evapotranspiration (ET) in this region since the primary productivity is directly linked to water availability. Information provided by satellite missions allows monitoring the spatial and temporal variability of ET. In the current study, we evaluated the version 006 of MOD16A2 product (MOD16A2.006) of Potential Evapotranspiration (ETp) and Actual Evapotranspiration (ETa) in Argentinian Pampas Region (APR). MOD16A2.006 product was compared with Crop Evapotranspiration (ETc), calculated with local measurements from the Oficina de Riesgo Agropecuario (ORA), and Crop Coefficient (Kc) data (f…
A Case For a Study Quality Appraisal in Survey Studies in Psychology
2019
The lack of replication of key effects in psychology has highlighted some fundamental problems with reporting of research findings and methods used (Asendorpf et al., 2013; Open Science Collaboration, 2015). Problems with replication have been attributed to sources of bias such as questionable research practices like HARK-ing (Kerr, 1998) or p-hacking (Simmons et al., 2011). Another potential source of bias is lack of precision in the conduct and methods used in psychological research, which likely introduces systematic error into data collected with the potential to affect results. A related issue is lack of accuracy in reporting study methods and findings. There is, therefore, increased r…
Three-prong τ decays with charged kaons
1998
Final states with charged kaons in three-prong τ decays are studied by exploiting the particle identification from the dE/dx measurement. The results are based on a sample of about 1.6 × 105 detected τ pairs collected with the ALEPH detector between 1991 and 1995 around the Z peak. The following branching ratios have been measured: B(τ- → K−K+π−ντ) = (1.63 ± 0.21 ± 0.17) × 10−3, B(τ− → K−π+π−ντ) = (2.14 ± 0.37 ± 0.29) × 10−3, B(τ− → K−K+π−π0ντ) = (0.75 ± 0.29 ± 0.15) × 10−3, and B(τ− → K−π+π−π0ντ) = (0.61 ± 0.39 ± 0.18) × 10−3. The first two measurements are more precise than the current world averages, while the last two channels are investigated for the first time. The 95% C.L. upper limi…
Source document verification in the Mucopolysaccharidosis Type I Registry
2011
Purpose The Mucopolysaccharidosis Type I (MPS I) Registry is an international observational database that tracks the natural history and the outcomes of patients with MPS I. The Registry was a regulatory requirement following the approval of laronidase enzyme replacement therapy for MPS I in 2003. All data are collected voluntarily after informed consent from the patient or family. Data are checked through queries, monthly reviews, and electronic audits to identify missing, inconsistent, or invalid data. This analysis sought to determine overall data accuracy in the Registry through source document verification (SDV). Methods Two phases of SDV were performed. In each phase, Registry data we…
Improved tau polarisation measurement
1996
Using 22 pb−1 of data collected at LEP in 1992 on the peak of the Z resonance, the ALEPH collaboration has measured the polarisation of the tau leptons decaying into $$ev\bar v, \mu v\bar v$$ ,πν, ρν and a1 ν from their individual decay product distributions. The measurement of the tau polarisation as a function of the production polar angle yields the two parametersN τ andN e, where, in terms of the axial and vector couplingsg Al andg Vl,N l=2g Vl gAl/(g Vl 2 +g 2 ). This analysis follows to a large extent the methods devised for the 1990 and 1991 data but with improvements which bring a better understanding of the systematic uncertainties. Combining the 1992 measurements with our previous…
Measurement of the positron longitudinal polarization in muon decay
1981
The longitudinal polarization of the ${e}^{+}$ from ${\ensuremath{\mu}}^{+}$ decay has been measured. The spin dependence of positron-electron (Bhabha) scattering and of annihilation in flight were used as the analyzing reactions. The combined statistical and systematic error was reduced by a factor of approximately 3 below that of any previous measurement. The longitudinal polarization was found to be 1.010\ifmmode\pm\else\textpm\fi{}0.064 (statistical plus systematic error) and to be consistent with the prediction of the $V\ensuremath{-}A$ interaction.
One is not enough: On the effects of reference genome for the mapping and subsequent analyses of short-reads.
2020
Mapping of high-throughput sequencing (HTS) reads to a single arbitrary reference genome is a frequently used approach in microbial genomics. However, the choice of a reference may represent a source of errors that may affect subsequent analyses such as the detection of single nucleotide polymorphisms (SNPs) and phylogenetic inference. In this work, we evaluated the effect of reference choice on short-read sequence data from five clinically and epidemiologically relevant bacteria (Klebsiella pneumoniae, Legionella pneumophila, Neisseria gonorrhoeae, Pseudomonas aeruginosa and Serratia marcescens). Publicly available whole-genome assemblies encompassing the genomic diversity of these species…
A measurement of the antineutrino asymmetry B in free neutron decay
2005
Abstract We have measured the antineutrino asymmetry B in neutron beta decay, i.e., the correlation of the neutron spin and the antineutrino momentum, with a new method. Our result is B = 0.967 ± 0.006 stat ± 0.010 syst = 0.967 ± 0.012 . Statistical and systematic uncertainty can be considerably reduced in future experiments.