Kinematic Cusps: Determining the Missing Particle Mass at Colliders

Understand

In many extensions of the SM, neutral massive stable particles (dark matter candidates) are produced at colliders in pairs due to an exact symmetry called a "parity".

• These particles escape detection, rendering their mass measurement difficult.
• In the pair production of such particles via a specific ("antler") decay topology, kinematic cusp structures are present in the invariant mass and angular distributions of the observable particles.
• Together with the end-points, such cusps can be used to measure the missing particle mass and the intermediate particle mass in the decay chain.