Yes, your undergrad research work is still your research experience, so definitely include it. Work does not need to be published to be included as experience. That's what the publications section of your CV can be used for. Depending on where you are in your career, you may or may not want to include details about your research experience. For example, undergrads and new grad students often include a few bullet points about each of their research experience, especially if the position was competitively awarded, for example. In this section, applicants often include the precise skills and contributions to the project and whether they have presented the work, or the current progress towards a paper etc. As people get more advanced in their careers, you'll find that senior grad students, postdocs and faculty members no longer list the specifics of each research project they undertake on their CV, as it would get far too long. Instead, you might see the position title and the location of the work. Maybe a thesis title and advisor name for the work related to a degree. These people have their publication history to provide the details of what they actually did.