$e^+e^- \rightarrow s\bar{s}$ at $\sqrt{s} = 250$ GeV at future linear colliders

Abstract

The forward--backward asymmetry ($A_{FB}$) in light-quark production is a sensitive probe of the electroweak sector and potential flavour-dependent BSM effects. We present a study of $e^+e^- \rightarrow s\bar{s}$ at $\sqrt{s}=250$ GeV at future linear colliders, using full ILD simulation and reconstruction tools for ILC and LCF@CERN. We assess the impact of particle identification on charge reconstruction and $A_{FB}$ extraction, considering software improvements using Comprehensive PID (CPID) for optimal $dE/dx$ usage, as well as hardware scenarios including cluster counting ($dN/dx$) and ideal TPC performance. Statistical precision gains are evaluated, with corrections for charge misidentification and acceptance applied. Results indicate that precise $A_{FB}^{s\bar{s}}$ measurements are feasible and that advanced PID is key to maximising sensitivity to electroweak and new-physics effects.

Figures (7)

• Figure 1: Kaon selection region in the $k$-distance plane used in cut 7.
• Figure 2: Comparison of the angular fits to the reconstructed and corrected data with respect to the parton level distributions. Plots for the $e_L^{-}e_R^{+}$ (left) and $e_R^{-}e_L^{+}$ (right) cases using $dE/dx$.
• Figure 3: Expected uncertainties for $s$$\overline{s}$ in the ILC250. Right: Comparing different hardware settings ($dE/dx$ vs $dN/dx$ in a pixel TPC vs An ideal TPC)
• Figure 4: Expected uncertainties for $s$$\overline{s}$ in the LCF@CERN250. Left: Comparing different software approaches ($dE/dx$ vs CPID $dE/dx$). Right: Comparing different hardware settings ($dE/dx$ vs $dN/dx$ in a pixel TPC vs An ideal TPC)
• Figure 5: Expected impact in the discrimination power for GHU models assuming a 1% (left) or 0.1% (right) uncertainty for $s$$\overline{s}$.