Search for Physics beyond the Standard Model in four- and three-top quark production

A reinterpretation of four-top quark ($t\bar{t}t\bar{t}$) production is presented using the full Run 2 dataset recorded by the CMS experiment, corresponding to an integrated luminosity of 138 fb$^{-1}$. The analysis targets BSM scenarios using the existing $t\bar{t}t\bar{t}$ production measurement, including constraints on effective field theory (EFT) operators, top-philic heavy resonances, and the top-Yukawa coupling. The results provide competitive limits on several new physics models and demonstrate the sensitivity of multi-top final states to a wide range of BSM effects.