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arXiv · 2511.00687

Electromagnetic deflection effects in the integrated luminosity measurement at the CEPC

Ivan Smiljanić·Ivanka Božović·Ivana Vidaković·Nataša Vukašinović·Goran Kačarević
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Abstract

In order to ensure measurement of the integrated luminosity with a relative precision of $\mathrm{10^{-4}}$ at the $\mathrm{Z^{0}}$ pole at CEPC, numerous systematic effects have to be quantified and, if possible, corrected for. Here we discuss the impact of electromagnetic fields of incoming bunches on the initial state electrons and positrons (EMD1) as well as on the Bhabha scattering final states (EMD2). Both effects change four-momenta of the final state particles, leading to a modification of the Bhabha count in the luminometer. These effects are quantified in simulation, together with their stability with respect to the beam parameters variations. Possible correction methods based on experimental measurements with the CEPC detector are discussed on a conceptual level.

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Ivan Smiljanić, Ivanka Božović, Ivana Vidaković, Nataša Vukašinović, Goran Kačarević. 2025-11-01. Electromagnetic deflection effects in the integrated luminosity measurement at the CEPC. https://arxiv.org/abs/2511.00687

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