Measurement of the running of the electromagnetic coupling at large momentum-transfer at LEP
The evolution of the electromagnetic coupling, α, in the momentum-transfer range 1800 GeV<sup>2</sup> < −Q<sup>2</sup> < 21600 GeV<sup>2</sup> is studied with about 40 000 Bhabha-scattering events collected with the L3 detector at LEP at centre-of-mass energ...
Guardado en:
| Autores principales: | , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
| Publicado: |
2005
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| Materias: | |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/79504 |
| Aporte de: |
| id |
I19-R120-10915-79504 |
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| record_format |
dspace |
| institution |
Universidad Nacional de La Plata |
| institution_str |
I-19 |
| repository_str |
R-120 |
| collection |
SEDICI (UNLP) |
| language |
Inglés |
| topic |
Ciencias Exactas Física Electromagnetismo L3 detector |
| spellingShingle |
Ciencias Exactas Física Electromagnetismo L3 detector Dova, María Teresa L3 Collaboration Measurement of the running of the electromagnetic coupling at large momentum-transfer at LEP |
| topic_facet |
Ciencias Exactas Física Electromagnetismo L3 detector |
| description |
The evolution of the electromagnetic coupling, α, in the momentum-transfer range 1800 GeV<sup>2</sup> < −Q<sup>2</sup> < 21600 GeV<sup>2</sup> is studied with about 40 000 Bhabha-scattering events collected with the L3 detector at LEP at centre-of-mass energies √s = 189–209 GeV. The running of α is parametrised as: <math><mi is="true">α</mi><mrow is="true"><mo is="true">(</mo><msup is="true"><mi is="true">Q</mi><mn is="true">2</mn></msup><mo is="true">)</mo></mrow><mo is="true">=</mo><mfrac is="true"><msub is="true"><mi is="true">α</mi><mn is="true">0</mn></msub><mrow is="true"><mn is="true">1</mn><mo is="true">−</mo><mi is="true">C</mi><mi mathvariant="normal" is="true">Δ</mi><mi is="true">α</mi><mo stretchy="false" is="true">(</mo><msup is="true"><mi is="true">Q</mi><mn is="true">2</mn></msup><mo stretchy="false" is="true">)</mo></mrow></mfrac><mo is="true">,</mo></math> where α<sub>0</sub> ≡ α(Q<sup>2</sup> = 0) is the fine-structure constant and C = 1 corresponds to the evolution expected in QED. A fit to the differential cross section of the e<sup>+</sup>e<sup>−</sup> → e<sup>+</sup>e<sup>−</sup> process for scattering angles in the range |cos θ| < 0.9 excludes the hypothesis of a constant value of α, C = 0, and validates the QED prediction with the result:
C = 1.05 ± 0.07 ± 0.14, where the first uncertainty is statistical and the second systematic. |
| format |
Articulo Articulo |
| author |
Dova, María Teresa L3 Collaboration |
| author_facet |
Dova, María Teresa L3 Collaboration |
| author_sort |
Dova, María Teresa |
| title |
Measurement of the running of the electromagnetic coupling at large momentum-transfer at LEP |
| title_short |
Measurement of the running of the electromagnetic coupling at large momentum-transfer at LEP |
| title_full |
Measurement of the running of the electromagnetic coupling at large momentum-transfer at LEP |
| title_fullStr |
Measurement of the running of the electromagnetic coupling at large momentum-transfer at LEP |
| title_full_unstemmed |
Measurement of the running of the electromagnetic coupling at large momentum-transfer at LEP |
| title_sort |
measurement of the running of the electromagnetic coupling at large momentum-transfer at lep |
| publishDate |
2005 |
| url |
http://sedici.unlp.edu.ar/handle/10915/79504 |
| work_keys_str_mv |
AT dovamariateresa measurementoftherunningoftheelectromagneticcouplingatlargemomentumtransferatlep AT l3collaboration measurementoftherunningoftheelectromagneticcouplingatlargemomentumtransferatlep |
| bdutipo_str |
Repositorios |
| _version_ |
1764820486835929090 |