B-tagging plays an important role in various physics searches in ATLAS. In particular, b-tagging can be sensitive to long-lived particles whose lifetime is within a certain region. I have been working on exotic resonance searches with b-tagging, b-tagging calibrations and long-lived particle reinterpretation with b-tagging involved. In this seminar I will share the lessons and experiences I've obtained and discuss several topics of interest.
