Just a little wee quibble here, but belief does matter in science, in fact in everything. You don't build a particle accelerator worth millions to detect previously undetected particles, for example, unless you believe they are out there.
http://public.web.cern.ch/public/en/science/higgs-en.html
Scientists believe in their theories or hypotheses. Good scientists don't hold on too tightly to those beliefs though, because they could be mistaken. And many have made the mistake of doing so.