You say "I do copyright my sheet music" - you copyright a piece of music as soon as it is 'fixated' in some sense through; musical score or recording (one or the other but not boh at the same time).

Copyright exists in the following ways:

LITRUGAL (Lyrics)
GRAPHICAL (Score)
AUDITORAL (Sound Recording)

Thus creating your 'IP - Intellectual Property'. There is no such thing as an 'official' way to copyright music, only as it is fixated does that piece become your Intellectual Proprty i.e. copyright. Therefore as your piece is instrumental and assuming you have not sold any publishing for this loop/sample, you therefore own this entire piece of Intellectual Property piece of music.

In UK law, no one is allowed to sample music which is seen to be a 'significant' part of the composition. Therfore, any more than a second - 0.01 - of your loop/sample used, therefore breaches your copyright.

Therefore, if you "own the copright" of that piece of music, no one is allowed to use/sample the audio or sheet music of your piece of music UNDER ANY CIRCUMSTANCES under Musical Copyrights of law.

You must state either "Copyright (YEAR)(COMPANY OR YOUR NAME). All rights reserved." OR " (YEAR)(COMPANY OR YOUR NAME). All rights reserved.".

Finally, as you uploaded this to www.looperman.com and are 'willingly' allowing others to use it, your copyright could be at risk of being void.

However, I believe this piece of music to be "Impressionalist" and has Late Romantic elements to this and not Neo-Classicism.

Hope this helps
PAUL
:)