日本のスノーアクティビティを体験 If the particle を is used here shouldn't it be 体験した/する if it is acting like a verb?
This is common headline style. In both English and Japanese, headlines are written in a clipped, abbreviated style. For example:
Queen to address parliament
Is a perfectly normal and comprehensible headline but would be unacceptable in speech or narrative prose. Omission of the する in する verbs, especially at the end of a headline, is common in Japanese. Here's a paper on the subject:
It's not really relevant in this case because 体験 sounds fine in casual speech, but another characteristic of Japanese headlines is strong reliance on 漢語, probably both for formality and to save space.