The role of Project Manager and Business Analyst

Business analyst will gather the requirement and will describe the scope of the project and the required quality. The business analyst is not responsible for the project success. He must make sure that the scope of the project is delivered.

Project manager has to go through the requirement and must fix the time line and the budget for the project. The project manager is responsible for the project success. 

In short the business analyst will provide the content for the project. The project manager has to provide the process for the given content.