Hi Rahul and Jack,
for sure acceptance criteria and success criteria are related to a certain extent. However, the way I see it, they operate at different levels; i.e., deliverable vs. project. So they focus on different aspects; we may say performance vs. requirements.
A project can be successful because it reached a target goal; e.g., improve a given metrics by 50%. This is not something to measure to decide whether the customer will accept a specific deliverable for that project. Instead, you (as the customer) may accept or reject a project deliverable based on the degree it meets the requirements. This is why the "Validate Scope" process derives "Accepted deliverables" as an output from the Requirements Mgmt plan, documentation, and traceability matrix (among other inputs).
Hope this clarifies a bit better the difference between the two.
Gabriella