Vessel head of research kept at absolute zero (11)
I believe the answer is:
dreadnought
'vessel' is the definition.
(dreadnought is a kind of vessel)
'absolute zero' is the wordplay.
'absolute' becomes 'dread' (I can't explain this - if you can you should give a lot more credence to this answer).
'zero' becomes 'nought' (synonyms).
'dread'+'nought'='DREADNOUGHT'
'head of research kept at' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for dreadnought that I've seen before include "Early 20th-century class of battleship" , "Large battleship" , "1905 class of battleship - grounded hat (anag)" , "Revolutionary British battleship (1906) - first British nuclear-powered submarine (1963)" , "Vessel" .)