I am applying to 8 schools in research area X of applied physics. I have some research experience in a very closely related area and one publication in a solid journal.
One of those schools has a professor working on very interesting topics in area Y. I emailed him and his reply was quite positive, saying I have an excellent record, but had the usual "the admissions committee makes the decisions not me, but I will be sure they carefully consider your application". I also know at this school we don't pick advisors till the summer of the first year. I have 3 years of experience in the theoretical side of area Y, 3 journal publications and a few talks/posters.
There are 3 scenarios I can think of:
Mention both X and Y, but I'm worried it would hurt my chances. I could focus mainly on X and mention Y in 1 or 2 sentences in my intro. I would also add 2 sentences to mention this professor's research near the end + 2 more professors from area X.
Mention only X, it makes me look more focused and this university has many more faculty in that area, but I'm worried this will burn bridges with the professor from area Y.
Mention only Y. I wouldn't be very keen on this as I would waste the tens of hours I spent on a mini-literature review of area X before writing my statement.
Edit: To clarify, I'm not asking whether I should mention my work on area Y or not. I certainly did mention all my prior research experience. I am asking whether it's okay to mention future interest in BOTH areas. e.g. "I am interested in topics A, B, C (from area X). Moreover, I am interested in topic D (from area Y)."