Hi @prasanthv I believe Experience A might be your Control version and Experience B is your Personalized version. Right ?
If Experience B introduces a new component that doesn't exist in Experience A, your goal metric setup in Adobe Target should align with what you want to measure.
So you can think of like overall engagement with your Experience B, interaction with Exp B or Conversion with Exp B. ...etc.
Once you define based on your use case, then chose the right goal metric like Conversion, Click, Pageviews, Engagement.
Refer - https://experienceleague.adobe.com/en/docs/target/using/activities/abtest/create/ab-set-metrics
https://experienceleague.adobe.com/en/docs/target/using/activities/success-metrics/success-metrics
In case if you want track interaction with Exp B with new component then you can setup a success metrics like click tracking, Time Spent, etc.
Make sure your goal must be aligned with your business objectives.
Hope this helps. If this satisfies your query please like, mark as helpful. Otherwise lets keep the conversation going.
Thanks