New research explores role of direction in understanding dark matter
New research on the direction of dark matter will help scientists build detectors that can distinguish between the mysterious particle they are searching for and background interference.
In a paper titled “Discriminating Dark Matter Origins with Directional Detection” scientists identified different sources of dark matter originating from the direction of a constellation called ‘Cygnus’, or from the Milky Way’s Galactic Centre.
PhD candidate Iman Shaukat Ali and her collaborators showed that dark matter originating from the galactic halo can be differentiated from its background more easily than dark matter produced in a supernova or scattered by cosmic rays.
The researchers studied low mass particles, calculating the signals from potential dark matter candidates when they were travelling from different directions and what those signals would look like in a detector that has directional sensitivity.
To do this the particle physics theorists modelled what the signal would look like in a detector with certain performance benchmarks, including sensitivity levels, and calculated the rate the dark matter would be approaching these detections.
The results point scientists towards identifying dark matter by providing important information on the incoming direction of dark matter and on the energy levels produced in collisions between dark matter and ordinary matter.
While conventional dark matter experiments measure the energy deposited in a detector, halo dark matter, cosmic ray-boosted dark matter and supernova-produced dark matter can produce remarkably similar results.
By understanding the direction of lightweight dark matter particles, it is far easier to identify their source, increasing scientists’ opportunities to detect dark matter, and to understand the particle itself.
“By measuring both the energy and arrival direction of recoil events, we gain a powerful tool for separating genuine dark matter signals from backgrounds that would otherwise be difficult to identify,” Ms Shaukat Ali said.
“I’m excited about this research because truly directional dark matter detectors are still in their infancy. As these technologies develop, they could provide exactly the level of sensitivity and discrimination needed to make a definitive dark matter discovery.”
Ms Shaukat Ali said she hoped the research would lead to further investigation of the directionality of boosted dark matter.
The research was conducted by a collaboration formed as a result of the ARC Centre of Excellence for Dark Matter Theory Workshop, including University of Melbourne researchers Iman Shaukat Ali, Nicole Bell and Jayden Newstead, and University of Sydney researchers Chiara Lisotti and Ciaran O’Hare.