Not exactly a scientific paper, but he wrote this essay about language: https://nautil.us/the-kekul-problem-236574/

Here’s an economics article at least: https://hbr.org/1996/07/increasing-returns-and-the-new-world...

And here’s a short article about his contribution to that article: https://andrewbatson.com/2016/12/13/cormac-mccarthys-contrib...

Cormac McCarthy was deeply interested in physics and mathematics and was a trustee at the Santa Fe Institute, which has a heritage connected with Los Alamos National Laboratory. I don't know a lot about this side of him, only reading about it after reading his last two novels which do show a mastery of physics that really seemed to mirror his master of bridles and guns and culture in the old west. I don't remember reading that he had actually published any of this himself but he was spoken of as intensely curious about physics.