Nuclear physics energy ranges (historic)---
10-3 to 100 in units of the proton mass mpc2.


Particle physics energy ranges (historic)---
0.1 to 104 in units of the proton mass.

RHIC at Brookhaven National Lab, Long Island (shut down early 2026)



Large Hadron Collider on the Swiss-French border. As of June 2026, the facility is shut down for 2 years to undergo extreme upgrades in energy, beam luminosity, and detector capabilities. 

Other important facilities: Jefferson Lab, an electron-ion collider; FAIR, under construction, an ion-antiproton collider; FRIB, a linear accelerator which creates nuclei very far from the line of stability, currently operational; and NICA/MPD, a heavy-ion collider currently under construction in Russia.


The original purpose for building scientific facilities rarely relates to their most important discoveries!


Sabine Hossenfelder on natural units.

The Klein-Gordon equation describes point spin-zero particles, the Dirac equation describes point spin-1/2 particles, the Proca equation describes point spin-1 particles, and point spin‑2 particles are described by the Volkov–Fock equation (also called the Bargmann–Wigner equation in its general form). NO EQUATIONS EXIST for point spin-3/2 or spin 3 particles, and none are known to exist in nature.


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