Не могу найти окно для процесса со статусом `Sl` [дубликат]

От man ps :

PROCESS STATE CODES

  Here are the different values that the s, stat and state output
  specifiers (header "STAT" or "S") will display to describe the state of
  a process:

       D    uninterruptible sleep (usually IO)
       R    running or runnable (on run queue)
       S    interruptible sleep (waiting for an event to complete)
       T    stopped, either by a job control signal or because it is
            being traced
       W    paging (not valid since the 2.6.xx kernel)
       X    dead (should never be seen)
       Z    defunct ("zombie") process, terminated but not reaped by
            its parent

  For BSD formats and when the stat keyword is used, additional
  characters may be displayed:

       <    high-priority (not nice to other users)
       N    low-priority (nice to other users)
       L    has pages locked into memory (for real-time and custom IO)
       s    is a session leader
       l    is multi-threaded (using CLONE_THREAD, like NPTL pthreads
            do)
       +    is in the foreground process group

(Так как Вы использовали aux, Вы работаете ps в режиме BSD.)

, Таким образом, у Вас есть многопоточный процесс, который в настоящее время спит.