Soooo basically it seems like my theory is wrong! I am no longer doing any nuclear physics research. I have no clue how they decide this kind of thing. It is so annoying!Hey, I'm also from Iran and have a PhD, been waiting for my BG since last October. I have no idea what their selection criteria is for security check. My work made me apply for a US visa (which I was obviously refused) and I thought that might be the reason, then I saw people with green card application getting their citizenship in 4 months. I know an Iranian phd guy who works in nuclear and got his citizenship in 3 months.