Speaker
Description
The top quark, as the most massive elementary particle, plays a crucial role in probing the electroweak sector and the flavour structure of the Standard Model (SM). Its decay hierarchy, dominated by the t → W b transition with highly sup- pressed t → W d/s channels, is governed by the Cabibbo-Kobayashi-Maskawa (CKM) matrix. Precision measurements of single-top quark production at the LHC offer a unique direct test of the third row of the CKM matrix (|Vtb|, |Vtd|, |Vts|), where significant deviations from the SM’s pronounced hierarchy could signal new physics. This talk will focus on the CMS measurements of the main single top quark production mechanisms, highlighting the information of the SM parameters that can be inferred from the couplings in production and decay of the top quark.