Abstract : A search for the quantum chromodynamics (QCD) critical point was performed by the STAR experiment at the Relativistic Heavy Ion Collider, using dynamical fluctuations of unlike particle pairs. Heavy-ion collisions were studied over a large range of collision energies with homogeneous acceptance and excellent particle identification, covering a significant range in the QCD phase diagram where a critical point may be located. Dynamical K/π, p/π, and K/p fluctuations as measured by the STAR experiment in central 0-5% Au+Au collisions from center-of-mass collision energies sNN−−−√ = 7.7 to 200 GeV are presented. The observable νdyn was used to quantify the magnitude of the dynamical fluctuations in event-by-event measurements of the K/π, p/π, and K/p pairs. The energy dependences of these fluctuations from central 0-5% Au+Au collisions all demonstrate a smooth evolution with collision energy.
