Chayan Majumdar (University College London) HEPEC 10.31.24
Title: Constraining the SMEFT with Right-Handed Neutrinos at FCC-ee
Abstract: The existence of right-handed neutrinos (RHNs), or heavy neutral leptons (HNLs), is strongly motivated by the observation of small but finite neutrino masses and mixings. In this talk, I will present the extended the Standard Model particle content with a pair of gauge-singlet fermions, which can be Dirac or Majorana in nature. Adopting a model-independent effective field theory (EFT) framework, more specifically NRSMEFT, we consider all possible operators of different Lorentz structures i.e., scalar (S), vector (V), and tensor (T) types with mass dimension 6 as well as neutral current operator. With these operators, I will discuss the future electron positron circular collider (FCC-ee) prospects constraining the corresponding new physics cut-off scale Λ in the monophoton channel with √s = 91.2 GeV at 100 ab−1 as well as √s = 240 GeV at 5 ab−1 integrated luminosities.
