Why in news?

The latest news in the field of dark matter is a dark matter detector experiment named LUX-ZEPLIN (LZ) in South Dakota in the U.S.

Highlights:

• As of today, this is the most sensitive dark matter detector in the world. To give an idea of the degree of difficulty in measuring evidence of a dark particle, it is said that the chamber of this LZ detector, can contain only one gram of dust if it is to detect a dark matter particle. This is the extent to which researchers have to go to rule out unwanted signals coming from other entities.

What is dark matter and why is it so elusive?

• All interactions in the universe are a result of four fundamental forces acting on particles — strong nuclear force, weak nuclear force, electromagnetic force and gravitation.
• Dark matter is made up of particles that do not have a charge — which means they do not interact through electromagnetic interactions. So, these are particles that are “dark”, namely because they do not emit light, which is an electromagnetic phenomenon, and “matter” because they possess mass like normal matter and hence interact through gravity.

• Gravitational force, besides not being fully integrated and understood by particle physicists, is extremely weak. For one thing, a particle that interacts so weakly becomes rather elusive to detect. This is because interactions from other known particles could drown out signals of dark matter particles.