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Beam-beam effects on the luminosity measurement at LEP and the number of light neutrino species
In e+e− collisions, electromagnetic effects caused by large charge density bunches modify the effective acceptance of the luminometer system of the experiments. These effects consequently bias the luminosity measurement from the rate of low-angle Bhabha interactions e+e−→e+e− . Surprisingly enough,...
| Autores principales: | , , , |
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| Lenguaje: | eng |
| Publicado: |
2019
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| Materias: | |
| Acceso en línea: | https://dx.doi.org/10.1016/j.physletb.2019.135068 http://cds.cern.ch/record/2687704 |
| _version_ | 1780963627409342464 |
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| author | Voutsinas, Georgios Perez, Emmanuel Dam, Mogens Janot, Patrick |
| author_facet | Voutsinas, Georgios Perez, Emmanuel Dam, Mogens Janot, Patrick |
| author_sort | Voutsinas, Georgios |
| collection | CERN |
| description | In e+e− collisions, electromagnetic effects caused by large charge density bunches modify the effective acceptance of the luminometer system of the experiments. These effects consequently bias the luminosity measurement from the rate of low-angle Bhabha interactions e+e−→e+e− . Surprisingly enough, the magnitude of this bias is found to yield an underestimation of the integrated luminosity measured by the LEP experiments by about 0.1%, significantly larger than the reported experimental uncertainties. When accounted for, this effect modifies the number of light neutrino species determined at LEP from the measurement of the hadronic cross section at the Z peak. |
| id | cern-2687704 |
| institution | Organización Europea para la Investigación Nuclear |
| language | eng |
| publishDate | 2019 |
| record_format | invenio |
| spelling | cern-26877042023-03-14T17:23:11Zdoi:10.1016/j.physletb.2019.135068http://cds.cern.ch/record/2687704engVoutsinas, GeorgiosPerez, EmmanuelDam, MogensJanot, PatrickBeam-beam effects on the luminosity measurement at LEP and the number of light neutrino speciesphysics.acc-phAccelerators and Storage Ringshep-phParticle Physics - Phenomenologyhep-exParticle Physics - ExperimentIn e+e− collisions, electromagnetic effects caused by large charge density bunches modify the effective acceptance of the luminometer system of the experiments. These effects consequently bias the luminosity measurement from the rate of low-angle Bhabha interactions e+e−→e+e− . Surprisingly enough, the magnitude of this bias is found to yield an underestimation of the integrated luminosity measured by the LEP experiments by about 0.1%, significantly larger than the reported experimental uncertainties. When accounted for, this effect modifies the number of light neutrino species determined at LEP from the measurement of the hadronic cross section at the Z peak.In $e^+ e^-$ collisions, electromagnetic effects caused by large charge density bunches modify the effective acceptance of the luminometer system of the experiments. These effects consequently bias the luminosity measurement from the rate of low-angle Bhabha interactions $e^+ e^- \to e^+ e^- $. Surprisingly enough, the magnitude of this bias is found to yield an underestimation of the integrated luminosity measured by the LEP experiments by about 0.1%, significantly larger than the reported experimental uncertainties. When accounted for, this effect modifies the number of light neutrino species determined at LEP from the measurement of the hadronic cross section at the Z peak.arXiv:1908.01704oai:cds.cern.ch:26877042019-08-06 |
| spellingShingle | physics.acc-ph Accelerators and Storage Rings hep-ph Particle Physics - Phenomenology hep-ex Particle Physics - Experiment Voutsinas, Georgios Perez, Emmanuel Dam, Mogens Janot, Patrick Beam-beam effects on the luminosity measurement at LEP and the number of light neutrino species |
| title | Beam-beam effects on the luminosity measurement at LEP and the number of light neutrino species |
| title_full | Beam-beam effects on the luminosity measurement at LEP and the number of light neutrino species |
| title_fullStr | Beam-beam effects on the luminosity measurement at LEP and the number of light neutrino species |
| title_full_unstemmed | Beam-beam effects on the luminosity measurement at LEP and the number of light neutrino species |
| title_short | Beam-beam effects on the luminosity measurement at LEP and the number of light neutrino species |
| title_sort | beam-beam effects on the luminosity measurement at lep and the number of light neutrino species |
| topic | physics.acc-ph Accelerators and Storage Rings hep-ph Particle Physics - Phenomenology hep-ex Particle Physics - Experiment |
| url | https://dx.doi.org/10.1016/j.physletb.2019.135068 http://cds.cern.ch/record/2687704 |
| work_keys_str_mv | AT voutsinasgeorgios beambeameffectsontheluminositymeasurementatlepandthenumberoflightneutrinospecies AT perezemmanuel beambeameffectsontheluminositymeasurementatlepandthenumberoflightneutrinospecies AT dammogens beambeameffectsontheluminositymeasurementatlepandthenumberoflightneutrinospecies AT janotpatrick beambeameffectsontheluminositymeasurementatlepandthenumberoflightneutrinospecies |