If I join with 'screen' to existing sessions, I can get a list of the sessions with C-a  keystroke and switch between them, however I can't find a way to safely leave/detach and keep all the processes running; if I press C-a \ it seems that it kills the processes.
screen manager with VT100/ANSI terminal emulation
fedora;process;gnu screen
Why do you use \ at all? The detach character is d.