Uncertainties from metrology in the integrated luminosity measurement with the updated design of a detector at CEPC

TL;DR

This paper evaluates the feasibility of measuring integrated luminosity with high precision at CEPC using a luminometer placed on the z-axis, considering detector design and beam properties.

Contribution

It presents an analysis of the luminosity measurement precision at CEPC with a new detector placement and updated beam parameters.

Findings

Feasibility of achieving $10^{-4}$ luminosity precision at CEPC.

Impact of luminometer placement on measurement accuracy.

Effect of post-CDR beam properties on luminosity measurement.

Abstract

In order to measure integrated luminosity with a required precision of $10^{-4}$ at the $Z^0$ pole, proposed CEPC $e^{+}e^{-}$ collider requires a luminometer, a specially designed calorimeter placed in the very forward region to identify Bhabha scattering at low polar angles. Usually, such a device is placed at the outgoing beams, to keep the spatial symmetries of the head-on collisions at accelerators with a non-zero crossing angle. At CEPC it is currently proposed to place the luminometer on the z-axis. We review a feasibility of a measurement of the integrated luminosity at the $Z^{0}$ pole with the required precision, concerning the luminometer centered around the z-axis and the post-CDR beam properties.