NPA Seminar: Jamie Karthein, MIT, “Fluctuations of Conserved Charges for QCD Phase Diagram Characterization” Abstract: Fluctuations provide a powerful tool for elucidating the nature of strongly-interacting matter in the QCD phase diagram. In heavy-ion-collision systems, the net-particle number fluctuations are captured at the moment of chemical freeze-out. Studies of the chemical freeze-out via susceptibilities from Lattice QCD and the Hadron Resonance Gas model contribute to the characterization of the transition region of the QCD phase diagram. In this talk, I will show how susceptibilities can be used to constrain interactions in the hadron gas phase, to study the interplay between different conserved charges via cross-correlators, and to determine signatures of a potential critical point in the QCD phase diagram [1,2,3]. 1. J. M. Karthein, V. Koch, C. Ratti, V. Vovchenko, Phys. Rev. D, 104, 094009 (2021) 2. R. Bellwied, S. Borsanyi et al, Phys. Rev. D, 101, 034506 (2020) 3. T. Dore, J.M. Karthein, D. Mroczek et al, Phys. Rev. D (accepted), arXiv:2207.04086 Recorded at Yale Wright Laboratory on November 10, 2022