A subatomic particle of a type including the baryons and mesons, which can take part in the strong interaction.

Note: The Large Hadron Collider is a large machine that collides hadrons, not a machine that collides large hadrons.

Note the hyphen. Plural: half-lives.

use hyphen

Not capitalised to Headquarters.

not helium 3

High-Energy Physics

Technology Transfer Network of institutions active in particle, astroparticle and nuclear physics

High Energy Stereoscopic System, a system of imaging atmospheric Cherenkov telescopes investigating cosmic gamma rays, located in Namibia

Acronym doesn’t need spelling out for the CERN Courier

not "high-tech"

Upper-case "H", lower-case "b".

Avoid the tautology "Higgs-boson particle". A boson is a particle; there is no need to repeat yourself. 

Named after the English physicist Peter Higgs, the Higgs boson is a subatomic particle whose existence is predicted by the theory that unified the weak and electromagnetic interactions.

Capital H, hyphen.

The ATLAS and CMS experiments have discovered a Higgs-like particle. They are not sure yet if it is the Higgs boson that the Standard Model predicts, or another, more exotic Higgs boson.

High-radiation materials test facility

High-Luminosity Large Hadron Collider, High-Luminosity LHC (also: HiLumi)

Capital letters, note the hyphen.

The High-Luminosity LHC project (HL-LHC) will take the accelerator to new energy frontiers.

Holland is a region in the western part of the Netherlands. Don't use "Holland" to mean the whole of the Netherlands – it's incorrect.

Acronym doesn’t need spelling out for the CERN Courier

Hubble Space Telescope

Spell out in first use then use acronym for the CERN Courier