arXiv subjects

Goran Kacarevic

Publications and source records attributed to Goran Kacarevic.

3 recordsLinked to original sources

arXiv2024

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

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.

hep-ex↗

arXiv2022

Systematic uncertainties in integrated luminosity measurement at CEPC

The very forward region is one of the most challenging regions to instrument at a future $e^+e^-$ collider. At CEPC, machine-detector interface includes, among others, a calorimeter dedicated for precision measurement of the integrated luminosity at a per mill level or better. Here we review a feasibility of such precision, from the point of view systematic effects arising from luminometer mechanical precision and positioning, beam-related requirements and physics background from two-photon processes. The impact of the beam energy spread and its uncertainty on the integrated luminosity precision is also discussed, as well as the achievable beam energy spread precision with the post-CDR CEPC beams.

physics.ins-det↗

arXiv2020

Beam-spread determination for luminosity measurement at CEPC

Any asymmetry in energy of the colliding beams will lead to a longitudinal boost of the center-of-mass frame of colliding particles w.r.t. the laboratory frame and consequently to the counting loss in luminometer due to the loss of colinearity of Bhabha final states. At CEPC running at the Z0 pole, asymmetry in energy of the colliding beams should be known as well as 12.5% of the beam-spread, in order to control the uncertainty of Bhabha count at the level of 0.01%. Here we discuss the method, initially proposed for FCCee, to determine variation of the beam-spread from the measurement of the effective center-of-mass energy in $e^+e^- \to μ^+μ^-$ collisions.

hep-ex↗