What is the definition of Hopefully Light Particles?

"Hopefully, light particles are the cosmic version of a bad joke gone wrong. Imagine stumbling upon a universe filled with 'hopefully light particles' - it's like finding out your morning coffee is actually a space bomb with a 99% chance of causing existential dread. Here's an edgy example sentence: 'The scientist stared at her data, hoping the elusive 'hopefully light particles' would finally reveal themselves, only to find out she'd just discovered the universe is more of a cosmic prankster than a benevolent deity.'"