Observation of a pseudoscalar excess at the $t\bar{t}$ threshold

Abstract

The CMS Collaboration recently observed a pseudoscalar excess of top quark-antiquark ($t\bar{t}$) events near the production threshold. One possible interpretation involves the formation of a short-lived quasi-bound state of $t\bar{t}$. This proceeding summarizes the first presentation of the results at the 59th Rencontres de Moriond and outlines its potential implications.

Comments: Contribution to the 2025 QCD session of the 59th Rencontres de Moriond