User research and UX research: Any difference?

On my first interview for a User Researcher role as an intern, I was asked this question by my mentor:

“What is the difference between User Research and User Experience Research"?

My immediate answer was that User Research and User Experience Research are the same and when then I followed up by saying UX Research measures users' experiences while User Research deals with user behaviors. I never thought that this question would come. Even today if you do a google search you will hardly find an article which talks about the differences or similarities of these two departments. The question here is should people even think about User Research and User Experience Research as two different and what will they even gain by knowing any differences or similarities between User Research and User Experience Research.

I tried searching online for articles that give me some differences between UX Research and User Research. They did not give any clear differences. Some say both are the same and some say User Research is more related to talking to people to know about their behaviors while UX Research is more about knowing about users' experiences with a product or a service. You must have read articles differentiating between Usability Testing and User Research and at the same time found articles that say Usability Testing is…