Source: Hindu

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Context

Dark matter remains one of the most enigmatic substances in astrophysics constituting five-sixths of the universe's matter. Recent developments have revised the minimum mass of dark matter particles.

Recent Methodology

Observations of the dwarf galaxy Leo II were critical. The density profile of dark matter within this galaxy revealed inconsistencies with previous mass limits.

 Researchers employed numerical simulations of the Schrödinger equation incorporating gravity to match theoretical density profiles with empirical data.

 Heavier dark matter particles better explain the concentrated mass in the inner regions of Leo II.

 The Revised Minimum Mass of Dark Matter Particles

Previous Estimate: The minimum mass of dark matter particles was thought to be approximately 10^−31 times the mass of a proton.

New Estimate: Theoretical physicists in May 2023 revised this limit increasing it to 2.3×10^−30 proton masses.

 This revision is a notable shift pushing the boundary of dark matter's characteristics by an order of magnitude.

About Dark Matter

Dark matter is an invisible substance that interacts weakly with ordinary matter and light.

It may exist uniformly or in clumps. Its presence is inferred from gravitational effects such as the rotation curves of galaxies and the motion of stars.

Local density is estimated at approximately two protons per teaspoon.

At cosmic scales dark matter density can be described as 0.0003 solar masses per cubic light year.

Implications of Particle Mass on Dark Matter Behavior

High-Mass Particles

Particles with 100 proton masses would have an inter-particle separation of about 7 cm making them pervasive in local environments.

Particles heavier than 10^19 proton masses result in separations exceeding the solar system, reducing their detectability.

Low-Mass Particles

For particles with masses as low as 10^−11 proton masses, quantum effects dominate requiring them to be considered as a fluid rather than discrete entities.

Extremely light particles (<10^−31 proton masses) would have wavelengths exceeding the size of dwarf galaxies making their existence incompatible with observed cosmic structures.

Astrophysics

The updated particle mass influences simulations of galaxy formation and structure.

It refines models of dark matter distribution across cosmic scales.

Particle Physics

Revising the mass range helps constrain theoretical models of dark matter particles such as WIMPs (Weakly Interacting Massive Particles) and axions.

Cosmology

Understanding dark matter properties is essential for explaining phenomena like gravitational lensing and cosmic microwave background radiation patterns.

Sources:

Hindu