Find Session(SID and Serial#) details using Process ID:

Find database session details using a process id(PID).

SELECT S.CLIENT_IDENTIFIER, s.status , s.TYPE , s.username , s.osuser , s.server ,
s.machine , s.module , s.logon_time , s.process , p.spid,
p.pid, s.SID, s.audsid, SYSDATE - (s.last_call_et / 86400) 
FROM gv$session s, gv$process p
WHERE s.paddr = p.addr(+) AND s.process ='&process';