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The only way that you'd have any legal recourse here is if you have some evidence to suggest that the reason you are being left out here is your race, religion, gender, age, disability or recent medical leave use. It's not otherwise illegal in employment law to be generally petty and exclusionary.
Leaving you off the list is not legally a statement, so it can't be used as a basis for a defamation claim (damage to your reputation). For you to have that sort of claim here, the CEO would have to have made a positive statement of fact which was false (like saying that you weren't invited because you kill puppies as a hobby...as an example). Just leaving you of the list is certainly a passive statement, but that's not illegal.
Regrettably, on these facts as they are stated here, I don't see any recourse for you.