Troops in conflict for antimatter (8)
I believe the answer is:
positron
'antimatter' is the definition.
(I know that positron is a type of antilepton)
'troops in conflict' is the wordplay.
'conflict' indicates an anagram (I've seen 'conflicting' mean this (conflicting can mean confusing or unclear)).
'troops'+'in'='troopsin'
'troopsin' anagrammed gives 'POSITRON'.
'for' is the link.
(Other definitions for positron that I've seen before include "A tiny thing" , "there's a small charge here" , "Charged particle" , "Sub-atomic particle" , "Elementary particle with positive charge" .)