Quantum entanglement is one of the defining features of quantum mechanics. In high-energy
colliders, quantum properties are experimentally accessible, the most important example being top
quark pair production at the LHC. This channel lead to the discovery of spin entanglement in 2024
[1-2].
In this work [3], we study how energetic final-state radiation modifies the spin entanglement of...
We study the sensitivity of top-quark pair production at the FCC-ee to heavy new physics, parametrised
in the Standard Model effective field theory, using discriminants based on matrix elements. The
analysis includes detector reconstruction effects, obtained with a fast simulation of the IDEA detector
concept, and jet flavour tagging. We consider dimension-six operators that modify the...
Measurements at electron-positron colliders can probe the scale evolution of quark masses predicted
by the Standard Model in several ways. LEP and SLD extracted mb(mZ) from three jet
rates in Z -> b bbar
decay. A future Z-pole run can improve the precision considerably, while a measurement
of mb at higher scale is possible from e+e- -> b bbar
production at 250 GeV and above. A
very precise...
