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

Abstract

In order to measure integrated luminosity with a required precision of 10−4 at the Z0 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 Z0 pole with the required precision, concerning the luminometer centered around the z-axis and the post-CDR beam properties.