Quarks, Axions and Other Particles - Sixty Symbols

Sixty Symbols
Sixty SymbolsMay 19, 2026

Why It Matters

Identifying the next particle—whether a supersymmetric partner, an axion, or another exotic state—would solve the dark‑matter mystery and test theories that bridge the sub‑atomic and cosmic realms, guiding future research investments.

Key Takeaways

  • Physicists suspect new particles between proton and Planck scales
  • Supersymmetry remains viable dark‑matter candidate despite LHC null results
  • Axions, light pseudoscalars, are strong contenders for dark‑matter detection
  • Top‑quark mass precision influences universe’s stability predictions for future
  • Experimental searches now target axions, chameleons, and symmetrons via novel methods

Summary

The video explores the possibility of undiscovered physics in the vast gap between the size of a proton and the Planck length, focusing on candidate particles that could fill this window. It highlights how theories such as extra‑dimensional models, cosmic strings, and inflationary scenarios motivate the search for new phenomena at these scales. Key insights include the continued relevance of supersymmetry as a dark‑matter framework despite the LHC’s lack of evidence, the growing interest in axions—light pseudoscalar particles originally proposed to solve the strong CP problem—and the role of massive fields during cosmic inflation. The discussion also touches on chameleon and symmetron theories that modify gravity, and how precision measurements of the top‑quark mass affect predictions about the universe’s long‑term stability. Notable moments feature a physicist’s description of axions as neutral, ultra‑light particles that interact only weakly with ordinary matter, and a vivid analogy about the top quark’s mass determining whether the cosmos sits in a stable or metastable vacuum. The host also interjects a personal anecdote about a high‑torque gear toy, underscoring the blend of serious science and playful curiosity. The implications are clear: upcoming experiments—ranging from dedicated axion haloscopes to gravitational‑wave searches for cosmic strings—could finally reveal the particle nature of dark matter or expose new forces. Such discoveries would reshape our understanding of fundamental physics, cosmology, and the ultimate fate of the universe.

Original Description

Ed Copeland and Tony Padilla answer questions about particles.
Metmo Gear Train at https://www.metmo.co.uk/collections/gear-train (discount code SIXTYSYMBOLS10OFF) (video sponsor)
More links and info below ↓ ↓ ↓
Some papers co-authored by Ed and/or Tony relating to this video...
From Inflation to Quintessence: a History of the Universe in String Theory: https://arxiv.org/abs/2407.03405
Modified Gravity and Cosmology: https://arxiv.org/abs/1106.2476
Formation and decay of oscillons after inflation in the presence of an external coupling: https://inspirehep.net/files/94b6bd94ddb8fe09fbdb84445148fe8d
Percolating Cosmic String Networks from Kination: https://arxiv.org/pdf/2406.12637
Fifth forces, Higgs portals and broken scale invariance: https://arxiv.org/pdf/1804.07180
This project features scientists from The University of Nottingham
Sixty Symbols videos by Brady Haran
Brady's chemistry channel is Periodic Videos - https://www.youtube.com/periodicvideos
And mathematics at Numberphile - https://www.youtube.com/numberphile
Some of the cover images in the video were partially AI-generated. Tony and Ed are 100% real.

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