I'm writing a timpani part for a concert band score. I've seen timpanist "choke" the note with their hand (on the head) after striking it to stop it from sustaining. How can I notate this?
Write the length of note you want. If you want notes separated by rests, write them. The timpanist will damp as necessary.
There are several symbols at my favorite reference such as "+" which indicate percussion instrument damping. I plead ignorance as to which symbols are applied to the tympani in particular. Search the linked page for the word "damp," and you'll see a couple crosshair-like symbols, sadly without comments as to applicability.