Beam-beam effects on the luminosity measurement at FCC-ee
| Autor: | Emmanuelle Perez, Patrick Janot, Georgios Voutsinas, M. Dam |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Accelerator Physics (physics.acc-ph)
Nuclear and High Energy Physics FOS: Physical sciences Electron 01 natural sciences High Energy Physics - Experiment Standard Model Nuclear physics High Energy Physics - Experiment (hep-ex) 0103 physical sciences Electroweak interaction lcsh:Nuclear and particle physics. Atomic energy. Radioactivity 010306 general physics physics.acc-ph Physics Luminosity (scattering theory) e+-e- Experiments 010308 nuclear & particles physics hep-ex Charge density Accelerators and Storage Rings e plus -e- Experiments Bunches lcsh:QC770-798 Physics - Accelerator Physics Beam (structure) Order of magnitude Particle Physics - Experiment |
| Zdroj: | Journal of High Energy Physics, Vol 2019, Iss 10, Pp 1-26 (2019) Voutsinas, G, Perez, E, Dam, M & Janot, P 2019, ' Beam-beam effects on the luminosity measurement at FCC-ee ', Journal of High Energy Physics, vol. 2019, no. 10, 225 . https://doi.org/10.1007/JHEP10(2019)225 Journal of High Energy Physics |
| ISSN: | 1029-8479 |
| Popis: | The first part of the physics programme of the integrated FCC (Future Circular Colliders) proposal includes measurements of Standard Model processes in $e^+e^-$ collisions (FCC-ee) with an unprecedented precision. In particular, the potential precision of the Z lineshape determination calls for a very precise measurement of the absolute luminosity, at the level of 1E-4, and the precision on the relative luminosity between energy scan points around the Z pole should be an order of magnitude better. The luminosity is principally determined from the rate of low-angle Bhabha interactions, $e^+e^- \to e^+e^-$, where the final state electrons and positrons are detected in dedicated calorimeters covering small angles from the outgoing beam directions. Electromagnetic effects caused by the very large charge density of the beam bunches affect the effective acceptance of these luminometers in a nontrivial way. If not corrected for, these effects would lead, at the Z pole, to a systematic bias of the measured luminosity that is more than one order of magnitude larger than the desired precision. In this note, these effects are studied in detail, and methods to measure and correct for them are proposed. Comment: Version 3: Now published in JHEP |
| Databáze: | OpenAIRE |
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