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.

arXiv commentContribution to the 2025 QCD session of the 59th Rencontres de Moriond