Unconventional Searches for Exotic Particles at Future Lepton Colliders

The main aim of the the Large Hadron Collider (LHC) experiments is to search for exotic particles with masses in the TeV range as predicted by Beyond Standard Model (BSM) theories. However, there is no hint of BSM around TeV scale so far. Hence, it is possible that the exotic particles are heavier and larger centre of mass energy is needed to observe them. Alternatively, the future lepton colliders offer a comparatively cleaner environment than the LHC which is advantageous to detect light exotic particles. Lepton colliders, like the International Linear Collider, provide the opportunity to detect exotic particles at energies below the TeV scale. The Muon Collider, once fully operational, will have the capability to observe exotic particles at and beyond the TeV scale. The search for BSM particles typically assumes a minimal scenario where only one type of BSM particle couples with the Standard Model (SM) sector. But there are theories which involve such interactions of multiple BSM particles. Here I discusses a specific model featuring a fermionic quintuplet and a scalar quartet that interact before decaying into SM particles. This model yields distinctive signatures characterized by high lepton and jet multiplicities, making it a promising candidate for detection at future lepton colliders.