This word is not acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

n. A measure of the velocity of a particle relative to that of a beam of particles, approximated by a function of its angle

"Jets above pseudorapidity of 3.5 or so are usually poorly reconstructed, and people have forgotten why its important."