Speaker
Description
When assessing the potential for discovering new physics beyond the Standard Model (SM) at the ILC and CLIC, a crucial role is assigned to the statistical treatment of experimental data, which is inherently linked to the specifics of the experimental setup and other factors. However, even in the absence of actual experimental data, it is possible to preliminarily estimate and study potential deviations from SM predictions caused by $Z^{\prime}$-bosons. The aim of this work is to develop and test a methodology for both model-independent and model-dependent analysis of the indirect manifestations of an additional $Z^{\prime}$-boson at the ILC and CLIC through the process $e^{+}e^{-} \to \gamma,Z^{0},Z^{\prime} \to \ell^{+}\ell^{-}$, where $\ell \neq e$. The study considers a scenario where the presumed mass of the $Z^{\prime}$-boson is significantly larger than the collider's energy and where future experimental data are consistent with the SM within one standard deviation. It is expected that the properties of the $Z^{\prime}$-boson can only be studied indirectly, namely by investigating deviations of the process observables from SM predictions; thus, in developing the methodology, the SM is treated as the background.
The developed methodology significantly differs from the traditional approach, as it explicitly accounts for the $Z^{\prime}$-boson width and interference effects. A key feature of the statistical analysis is the incorporation of non-linearity, since all characteristics of the $Z^{\prime}$ are contained non-linearly in the representation of the cross-section for the process under study. It is important to note that the option of longitudinal beam polarization is crucial for implementing this methodology, as it allows for the separation and independent analysis of different contributions. The paper evaluates the possibilities of improving the constraints on the characteristics of the $Z^{\prime}$ boson on ILC and CLIC.
