Please forgive my Neanderthal naiveté, but what, may I ask, is "Xenu"?
"not really sure that the answer will improve my quality of life"
According to some Scientologists, and I'm not one, nor do I play one on TV, and to the best of my knowledge, Xenu is a space alien, representative of the many space aliens which inhabit human bodies. They are bad naughty space aliens.
Apparently it is the job of a Scientologist auditor to help other humans to rid themselves of space aliens.
If you join the Church of Scientology, pay a lot of money and go through many auditing sessions (around $400/hour and up) eventually you will reach a level where you will have a clearer understanding of Xenu. They might even let you shake hands with Tom Cruise.