Observation of an excess at 30 GeV in the opposite sign di-muon spectra of ${\rm Z} \to b\overline{ b} + {\rm X}$ events recorded by the ALEPH experiment at LEP

The re-analysis of the archived data recorded at the ${\rm Z}^{0}$ resonance by the ALEPH experiment at LEP during the years 1992-1995 shows an excess in the opposite sign di-muon mass spectra at 30.40 GeV in events containing b quarks. The excess has a natural width of 1.78 GeV. A compatible but sm...

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Detalles Bibliográficos
Autor principal: Heister, Arno
Lenguaje:eng
Publicado: 2016
Materias:
Particle Physics - Experiment
Acceso en línea:http://cds.cern.ch/record/2226690
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author Heister, Arno
author_facet Heister, Arno
author_sort Heister, Arno
collection CERN
description The re-analysis of the archived data recorded at the ${\rm Z}^{0}$ resonance by the ALEPH experiment at LEP during the years 1992-1995 shows an excess in the opposite sign di-muon mass spectra at 30.40 GeV in events containing b quarks. The excess has a natural width of 1.78 GeV. A compatible but smaller excess is visible in the opposite di-electron mass spectrum as well.
id cern-2226690
institution Organización Europea para la Investigación Nuclear
language eng
publishDate 2016
record_format invenio
spelling cern-22266902021-05-03T08:15:52Zhttp://cds.cern.ch/record/2226690engHeister, ArnoObservation of an excess at 30 GeV in the opposite sign di-muon spectra of ${\rm Z} \to b\overline{ b} + {\rm X}$ events recorded by the ALEPH experiment at LEPParticle Physics - ExperimentThe re-analysis of the archived data recorded at the ${\rm Z}^{0}$ resonance by the ALEPH experiment at LEP during the years 1992-1995 shows an excess in the opposite sign di-muon mass spectra at 30.40 GeV in events containing b quarks. The excess has a natural width of 1.78 GeV. A compatible but smaller excess is visible in the opposite di-electron mass spectrum as well.The re-analysis of the archived data recorded at the ${\rm Z}^{0}$ resonance by the ALEPH experiment at LEP during the years 1992-1995 shows an excess in the opposite sign di-muon mass spectra at 30.40 $\pm$ 0.46 GeV in events containing b quarks. The excess has a natural width of 1.78 $\pm$ 1.14 GeV. The di-muon excess has a local significance around $5\,\sigma$ ($Z_{\rm asym}$), depending on the background model used. The significances for background models based on a kernel density approximation stay close to $3\,\sigma$ ($Z_{\rm freq,\,lee}$), when including a look elsewhere effect. Another method to obtain a significance value results in at least $2.6\,\sigma$ ($Z_{\rm Bi}$). A compatible, but smaller excess is visible in the opposite di-electron mass spectrum as well. This paper uses the data collected by the ALEPH experiment in the years 1992-1995, which have been archived to allow their use for physics analyses after the closure of the collaboration.arXiv:1610.06536oai:cds.cern.ch:22266902016-10-20
spellingShingle Particle Physics - Experiment
Heister, Arno
Observation of an excess at 30 GeV in the opposite sign di-muon spectra of ${\rm Z} \to b\overline{ b} + {\rm X}$ events recorded by the ALEPH experiment at LEP
title Observation of an excess at 30 GeV in the opposite sign di-muon spectra of ${\rm Z} \to b\overline{ b} + {\rm X}$ events recorded by the ALEPH experiment at LEP
title_full Observation of an excess at 30 GeV in the opposite sign di-muon spectra of ${\rm Z} \to b\overline{ b} + {\rm X}$ events recorded by the ALEPH experiment at LEP
title_fullStr Observation of an excess at 30 GeV in the opposite sign di-muon spectra of ${\rm Z} \to b\overline{ b} + {\rm X}$ events recorded by the ALEPH experiment at LEP
title_full_unstemmed Observation of an excess at 30 GeV in the opposite sign di-muon spectra of ${\rm Z} \to b\overline{ b} + {\rm X}$ events recorded by the ALEPH experiment at LEP
title_short Observation of an excess at 30 GeV in the opposite sign di-muon spectra of ${\rm Z} \to b\overline{ b} + {\rm X}$ events recorded by the ALEPH experiment at LEP
title_sort observation of an excess at 30 gev in the opposite sign di-muon spectra of ${\rm z} \to b\overline{ b} + {\rm x}$ events recorded by the aleph experiment at lep
topic Particle Physics - Experiment
url http://cds.cern.ch/record/2226690
work_keys_str_mv AT heisterarno observationofanexcessat30gevintheoppositesigndimuonspectraofrmztoboverlinebrmxeventsrecordedbythealephexperimentatlep

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