TY  - JOUR
PB  - SciPost Foundation
DO  - 10.21468/SciPostPhys.18.5.152
TI  - New physics through flavor tagging at FCC-ee
PY  - 2025/05/12
UR  - https://scipost.org/SciPostPhys.18.5.152
JF  - SciPost Physics
JA  - SciPost Phys.
VL  - 18
IS  - 5
SP  - 152
A1  - Greljo, Admir
AU  - Tiblom, Hector
AU  - Valenti, Alessandro
AB  - Leveraging recent advancements in machine learning-based flavor tagging, we develop an optimal analysis for measuring the hadronic cross-section ratios $R_b$, $R_c$, and $R_s$ at the FCC-ee during its $WW$, $Zh$, and $t\bar{t}$ runs. Our results indicate up to a two-order-of-magnitude improvement in precision, providing an unprecedented test of the SM. Using these observables, along with $R_\ell$ and $R_t$, we project sensitivity to flavor non-universal four-fermion (4F) interactions within the SMEFT, contributing both at the tree-level and through the renormalization group (RG). We highlight a subtle complementarity with RG-induced effects at the FCC-ee's $Z$-pole. Our analysis demonstrates significant improvements over the current LEP-II and LHC bounds in probing flavor-conserving 4F operators involving heavy quark flavors and all lepton flavors. As an application, we explore simplified models addressing current $B$-meson anomalies, demonstrating that FCC-ee can effectively probe the relevant parameter space. Finally, we design optimized search strategies for quark flavor-violating 4F interactions.
ER  -

@Article{10.21468/SciPostPhys.18.5.152,
	title={{New physics through flavor tagging at FCC-ee}},
	author={Admir Greljo and Hector Tiblom and Alessandro Valenti},
	journal={SciPost Phys.},
	volume={18},
	pages={152},
	year={2025},
	publisher={SciPost},
	doi={10.21468/SciPostPhys.18.5.152},
	url={https://scipost.org/10.21468/SciPostPhys.18.5.152},
}