The below query we can get sid,serial#,spid of the concurrent request

SELECT a.request_id,

       d.sid,

       d.serial#,

       c.spid

  FROM apps.fnd_concurrent_requests a,

       apps.fnd_concurrent_processes b,

       v$process c,

       v$session d

 WHERE     a.controlling_manager = b.concurrent_process_id

       AND c.pid = b.oracle_process_id

       AND b.session_id = d.audsid

       AND a.request_id = &request_id

       AND a.phase_code = 'r';