Distinguishing two dark matter component particles at e + e − colliders
Subhaditya Bhattacharya (Department of Physics, Indian Institute of Technology Guwahati, North Guwahati, Assam, 781039, India); Purusottam Ghosh (School Of Physical Sciences, Indian Association for the Cultivation of Science, 2A and 2B, Raja S.C. Mullick Road, Kolkata, 700032, India); Jayita Lahiri (Department of Physics, Indian Institute of Technology Guwahati, North Guwahati, Assam, 781039, India); Biswarup Mukhopadhyaya (Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, India)
We investigate ways of identifying two kinds of dark matter (DM) component particles at high-energy colliders. The strategy is to notice and distinguish double-peaks(humps) in the missing energy/transverse energy distribution. The relative advantage of looking for missing energy is pointed out, in view of the fact that the longitudinal component of the momentum imbalance becomes an added input. It thus turns out that an electron-positron collider is better suited for discovering a two-component DM scenario, so long as both of the components are kinematically accessible. This and a number of associated conclusions are established, using for illustration a scenario including a scalar and a spin-1/2 particle. We also formulate a set of measurable quantities which quantify the distinguishability of the two humps, defined in terms of double-Gaussian fits to the missing energy distribution. The efficacy of these variables in various regions of the parameter space is discussed, using the aforesaid model as illustration.
