particle physics vs high-energy physics

particle physics and high-energy physics both are nouns.

Word	Noun	Adjective	Verb	Adverb
particle physics	Yes	No	No	No
high-energy physics	Yes	No	No	No

As nouns, particle physics and high-energy physics are synonyms defined as:

particle physics and high-energy physics: the branch of physics that studies subatomic particles and their interactions

Other synonyms of particle physics include high energy physics.

particle physics (noun)	high-energy physics (noun)
the branch of physics that studies subatomic particles and their interactions	the branch of physics that studies subatomic particles and their interactions