I am planning to apply for top theoretical particle physics Ph.D programs, and I do have a solid research experience in my undergraduate. But I'm concerning that none of my research was about theoretical or particle physics. (done some condensed matter, AMO experimental researches.)
I know it's still better to have any types of research than nothing, but I'm wondering how much.
Would grad school expect students to have research experience in the field they are applying for? Do students with no relevant experience even have a chance to be considered?