Top pair production and spin correlations near threshold.

by Paolo Nason (Milano-Bicocca U.)

Monday 26 Jan 2026, 16:00 → 18:00 Europe/Rome

Aula Conversi (Dipartimento di Fisica-Ed.G.Marconi)

The CMS and ATLAS experiments have observed spin correlation effects and a cross section excess near threshold in top-antitop production at the LHC. They have attempted to explain these observation by assuming that they arise from the contribution of a top-antitop bound state to the production cross section. I will discuss the dynamics of top-antitop production and of their spin correlations near threshold, that is dominated by non-relativistic Quantum Chromodynamics Coulombic interaction. This discussion is realtively elementary, since it is carried out in the context of non-relativistic quantum mechanics. I will show that when all non-relativistic effects are included, the description of the phenomenon cannot simply be represented by the production of a bound state, and that, on the other hand, the dominant effects are calculable in perturbation theory. Finally I will assess the current status of the comparison of the experimental measurements with the theoretical calculation.

Zoom link: https://uniroma1.zoom.us/j/87038625161?pwd=cEtGRjZNT2VWSlJIWmxaYmxSMDhRZz09

Roma-26-1-2026.pdf