Distinguishing two dark matter component particles at \(e^+e^-\) colliders

Abstract

In this work we demonstrate that a distorted double hump like missing energy (\(\slashed{E}\)) or missing transverse momentum (\(\slashed{E}_T\)) or missing mass (\(\slashed{M}\)) distribution at \(e^+e^-\) colliders may hint towards the presence of multipartite dark sector. We illustrate the phenomena using a two component dark matter (DM) model involving an inert scalar doublet stabilised under a \(\mathcal{Z}_2\) symmetry providing a scalar DM, one vector like fermion doublet and a right handed fermion singlet both stabilised under a different \(\mathcal{Z}^{'}_2\) providing a fermion DM. We indicate the region of parameter space where the production of the heavy charged particles and their subsequent decay to DM yield double peak behaviour in \(\slashed{E}\) spectrum after satisfying DM constraints. Importantly, we illustrate why and how \(\slashed{E}\) serves as a better variable than \(\slashed{E}_T\) in distinguishing two component DM frameworks and therefore how International Linear Collider (ILC) does better than the ongoing Large Hadron Collider (LHC). We also chalk out a set of criteria to identify and segregate the second peak in \(\slashed{E}\) spectrum, after a careful analysis of the corresponding Standard Model (SM) background contribution, which plays a crucial role.