usa – UK US tax treaty J1 visa Article 20: Do researchers count as “professors or teachers”?

I’m in the US doing research, and from the UK. I’d like to claim the UK-US tax exemption. I think that I am eligble, as my role is completely research based. However my HR department isn’t sure as I’m not technically a “professor” or “teacher” (the language stated in the tax treaty, although neither term is defined in the document). Other people I know at different institutions seem to be sure that I qualify. Can anyone provide a reference for me to show to my HR department to convince them.