The stopping of the listener doesn't quit the connection between the two databases. The Listener of the Data Guard only initiates the first connection. After that it establishesh socket connection between the processes on Primary and Standby. Is that so?
yes that is true once the connection is established between the two session. Even if the listener is stopped the connection exist. Listener is only responsible for the accepting connection, validating it and establishing the connection. Once the connection is made it has no further role.