What's the noun for researchers? Here's the word you're looking for.
research
(uncountable) Diligent inquiry or examination to seek or revise facts, principles, theories, applications, etc.; laborious or continued search after truth.
(countable) A particular instance or piece of research.
“The researchee for this clinical trial will be selected based on specific inclusion criteria and will undergo various assessments to evaluate treatment efficacy.”
“Most inquiry has focussed on the researchee, while only limited attention has been given to the researcher.”