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The FIT-pull Method: an experimental tool to monitor the track measurements and the B proper time.

In this note we describe a statistical tool, the \textit{FIT-pull method}, that can test the reliability of the measurements of the tracks and the vertices on real and Monte-Carlo data without knowledge of the truth information. The basic mathematical formalism is derived from the Lagrange Multiplie...

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Detalles Bibliográficos
Autores principales: Balbi, G, Vagnoni, V M, Vecchi, S
Lenguaje:eng
Publicado: 2007
Materias:
Acceso en línea:http://cds.cern.ch/record/1039136
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author Balbi, G
Vagnoni, V M
Vecchi, S
author_facet Balbi, G
Vagnoni, V M
Vecchi, S
author_sort Balbi, G
collection CERN
description In this note we describe a statistical tool, the \textit{FIT-pull method}, that can test the reliability of the measurements of the tracks and the vertices on real and Monte-Carlo data without knowledge of the truth information. The basic mathematical formalism is derived from the Lagrange Multipliers method and briefly described. Several tests are performed to prove its validity in different situations. %KDifferent useful examples are discussed. In particular, by using Monte-Carlo simulation, we demonstrate that the method can be applied to check if the measured tracks or vertices have biases or incorrect covariance matrices. For correct input measurements we obtain pull distributions with a normal Gaussian statistical form. In this case the B proper time value and its error, which is a function of the track and vertex measurements, are correctly calculated. However, in the case of incorrect measurements, for example due to a systematic error or to a scale factor of the covariance matrix, the pull distributions studied deviate from normal Gaussians and the B proper time measurement can be affected. In principle the method can, if necessary, be used to recover information from corrupted measurements. Its potential in this capacity is demonstrated for the particular case of the decay channel $B^0_d \to \pi^+ \pi^-$ with the reconstructed Monte-Carlo data produced in 2004.
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institution Organización Europea para la Investigación Nuclear
language eng
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spelling cern-10391362019-09-30T06:29:59Zhttp://cds.cern.ch/record/1039136engBalbi, GVagnoni, V MVecchi, SThe FIT-pull Method: an experimental tool to monitor the track measurements and the B proper time.Detectors and Experimental TechniquesIn this note we describe a statistical tool, the \textit{FIT-pull method}, that can test the reliability of the measurements of the tracks and the vertices on real and Monte-Carlo data without knowledge of the truth information. The basic mathematical formalism is derived from the Lagrange Multipliers method and briefly described. Several tests are performed to prove its validity in different situations. %KDifferent useful examples are discussed. In particular, by using Monte-Carlo simulation, we demonstrate that the method can be applied to check if the measured tracks or vertices have biases or incorrect covariance matrices. For correct input measurements we obtain pull distributions with a normal Gaussian statistical form. In this case the B proper time value and its error, which is a function of the track and vertex measurements, are correctly calculated. However, in the case of incorrect measurements, for example due to a systematic error or to a scale factor of the covariance matrix, the pull distributions studied deviate from normal Gaussians and the B proper time measurement can be affected. In principle the method can, if necessary, be used to recover information from corrupted measurements. Its potential in this capacity is demonstrated for the particular case of the decay channel $B^0_d \to \pi^+ \pi^-$ with the reconstructed Monte-Carlo data produced in 2004.LHCb-2007-032CERN-LHCb-2007-032oai:cds.cern.ch:10391362007-06-20
spellingShingle Detectors and Experimental Techniques
Balbi, G
Vagnoni, V M
Vecchi, S
The FIT-pull Method: an experimental tool to monitor the track measurements and the B proper time.
title The FIT-pull Method: an experimental tool to monitor the track measurements and the B proper time.
title_full The FIT-pull Method: an experimental tool to monitor the track measurements and the B proper time.
title_fullStr The FIT-pull Method: an experimental tool to monitor the track measurements and the B proper time.
title_full_unstemmed The FIT-pull Method: an experimental tool to monitor the track measurements and the B proper time.
title_short The FIT-pull Method: an experimental tool to monitor the track measurements and the B proper time.
title_sort fit-pull method: an experimental tool to monitor the track measurements and the b proper time.
topic Detectors and Experimental Techniques
url http://cds.cern.ch/record/1039136
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