Pomeriggio tematico sul Toponio

Tuesday 9 Dec 2025, 16:00 → 18:00 Europe/Rome

Aula Conversi (Dip. di Fisica - Edificio G. Marconi)

16:00 → 16:40 Intro teorica

Speaker: Antonio Davide Polosa (Istituto Nazionale di Fisica Nucleare)

16:45 → 17:30 Spot on the tt̄ threshold: quasi-bound states or BSM Physics?

Recent measurements by CMS and ATLAS at the LHC have independently revealed an intriguing excess near the top quark–antiquark production threshold. In this seminar, I will present the CMS analysis in the dileptonic channel based on the full Run II dataset. The observed excess is compatible with contributions from a short-lived ¹S₀ quasi-bound state (“toponium”), but can also be interpreted in terms of heavy scalar or pseudoscalar resonances. A comparison with the ATLAS result and prospects for clarifying the origin of this enhancement in future measurements will be discussed.

Speaker: Alexander Grohsjean (Deutsches Elektronen Synchrotron)