Experts favoured limiting constant expectation (8)
I believe the answer is:
prospect
'expectation' is the definition.
(I've seen this before)
'experts favoured limiting constant' is the wordplay.
'experts' becomes 'pros' (I've seen this in other clues).
'favoured' becomes 'pet' (as in a pet project).
'limiting' means one lot of letters goes inside another.
'constant' becomes 'c' (mathematical abbreviation).
'pet' going around 'c' is 'pect'.
'pros'+'pect'='PROSPECT'
(Other definitions for prospect that I've seen before include "Outlook or panorama" , "Chance of success" , "Someone who might buy" , "View - outlook" , "Possibility; wide view" .)