Quest for Dark Matter: A Struggle Against the ‘Neutrino Fog’
- September 30, 2024
- Posted by: OptimizeIAS Team
- Category: DPN Topics
Quest for Dark Matter: A Struggle Against the ‘Neutrino Fog’
Sub : Sci
Sec: Space
Why in News
On August 28, 2024, members of the LUX-ZEPLIN (LZ) experiment presented a significant announcement at conferences in Chicago and São Paulo. The LZ experiment, situated 1.5 kilometers below the Earth’s surface at the Sanford Underground Research Facility in South Dakota, achieved a major milestone in the search for dark matter.
What is Dark Matter?
Dark matter makes up around 85% of the matter in the known universe, but because it doesn’t interact with light it is practically invisible.Likewise, whatever the constituent particles of dark matter are, they don’t interact strongly with other matter either.
Mass Contribution: Stars, planets, and gas make up only 15% of the universe’s mass, with the remaining 85% attributed to dark matter.
Age: Dark matter is believed to have existed since the birth of the universe, around 14 billion years ago.
The only way scientists can infer the presence of dark matter is via its gravitational influence which literally holds together most galaxies, preventing their constituent stars from flying apart as they spin.
Dark matter isn’t made up of protons and neutrons like the everyday matter.
The Neutrino Fog: A Major Obstacle
As detectors become larger, they encounter noise from neutrinos, particles emitted by the Sun and Earth’s atmosphere.Distinguishing between dark matter signals and neutrino signals becomes increasingly difficult, a phenomenon termed the ‘neutrino fog.’
What are neutrinos?
Neutrinos are the second most abundant particles in the world, after photons, or the light particle.Neutrinos are mysterious particles, produced copiously in nuclear reactions in the Sun, stars, and elsewhere.
They also “oscillate”– meaning that different types of neutrinos change into one another.Probing of oscillations of neutrinos and their relations with mass are crucial in studying the origin of the universe.
Neutrinos are created by various radioactive decays; during a supernova, by cosmic rays striking atoms etc.
What is LUX-ZEPLIN experiment?
TheLUX-ZEPLIN detector is set up to specifically search for a hypothesized type of dark matter called weakly interacting massive particles, or WIMPs
These particles are expected to collide with matter very rarely and interact extremely weakly when they do.
No dark matter particles have currently been directly detected, but the hope is that the LZ detector could change that by detecting the faint interactions of these mysterious particles with xenon atoms
This requires a sensitive detector with all possible noise that could interfere with detection eliminated.
TheLZ experiment’s xenon is in two nested titanium tanks containing ten tons of the elements in its liquid state.
These tanks are monitored by two photo multiplier tube (PMT) arrays which are poised to detect faint sources of light
It is Located deep below the Black Hills of South Dakota, US. The underground location of the dark matter detector helps protect it from high-energy protons and atomic nuclei that move through space at nearly the speed of light
Goodman-Witten (GW) Strategy: In 1985, physicists Mark Goodman and Edward Witten proposed a method to detect dark matter particles. The idea was to place a chunk of metal deep underground, shielded from other cosmic radiation.If dark matter particles collided with the atomic nuclei in the metal, the nuclei would recoil, signaling the presence of dark matter.
This strategy aimed to measure two unknowns: the mass of the dark matter particle and the rate of its interaction with atomic nuclei, referred to as the scattering cross-section. This idea laid the foundation for modern dark matter detection experiments.
Other Experiments
XENON-nT:XENON-nT is a next-generation dark matter detection experiment located at the Gran Sasso Laboratory in Italy. It aims to detect weakly interacting massive particles (WIMPs), a prime candidate for dark matter.
The detector contains a large tank of liquid xenon, which is expected to interact with dark matter particles and produce detectable signals.
PandaX-4T:PandaX-4T, located in the China Jinping Underground Laboratory, is another dark matter detection experiment designed to search for WIMPs.
Like XENON-nT, it uses liquid xenon as the detection medium. PandaX-4T boasts a highly sensitive and large-scale setup, allowing it to detect potential signals of dark matter and new particles.