Su Houng Lee

Observing the mass shifts of mesons immersed in nuclear matter is interesting, as the changes are expected to shed light on the effects of chiral symmetry breaking on the origin of hadron masses. At the same time, it is important to understand the momentum dependence of the masses for spin-1 mesons, as the changes manifest differently across the two polarization modes. Here, the mass shifts of K1± mesons with finite three-momentum in nuclear medium are studied in the QCD sum rule approach.

Observing the mass shifts of chiral partners will provide invaluable insight into the role of chiral symmetry breaking in the generation of hadron masses. Because both the K* and K1 mesons have vacuum widths smaller than 100 MeV, they are ideal candidates for realizing mass shift measurements. On the other hand, the different momentum dependence of the longitudinal and transverse modes smear the peak positions.

We extend the recent study of K1/K* enhancement as a signature of chiral symmetry restoration in heavy ion collisions at the CERN Large Hadron Collider via the kinetic approach to include the effects due to nonunity hadron fugacities during the evolution of produced hadronic matter and the temperature-dependent K1 mass.