The 2023 International Workshop on the High Energy Circular Electron Positron Collider

Lattice simulations have established that the gluon propagator in the linear covariant gauges saturates to a finite value at the origin, signaling the emergence of a gluon mass scale in QCD. The Schwinger mechanism, a framework for generating masses for gauge Bosons without breaking the gauge symmetry of the underlying theory, provides an explanation of this observation. We briefly review how...

We consider, at order $\alpha^2$ in the QCD coupling, top-quark pair production in the continuum at various center-of-mass energies and $b$-quark pair production at the $Z$ resonance by (un)polarized electron and positron beams. For top quarks we compute the forward-backward asymmetry with respect to the top-quark direction of flight, the associated polar angle distribution, and we analyze...

We present the first complete high-precision QCD corrections to the inclusive decay width $\Gamma_t$, the W-boson helicity fractions and semi-inclusive distributions for the top-quark decay process $t \rightarrow b + W^+ + X$ at next-to-next-to-next-to leading order (NNNLO) in the strong coupling constant $\alpha_s$. In particular, with the Standard Model parameters used in our calculations,...