Speaker
Description
X.-N. Zhu, Defu Hou, X.-L. Sheng, Phys. Rev. D 112, 056011 (2025)
We develop a theoretical framework for the production of K+K- pairs through the decay of ϕ mesons produced from a thermal background, based on the Nambu-Jona-Lasinio (NJL) model. The differential production rate of K+K- is related to the self-energy of the ϕ meson, incorporating the contributions of the quark loop at leading order and the kaon loop at next-to-leading order in the 1/Nc expansion. We numerically evaluate the invariant mass spectrum of the K+K- pair both in vacuum and at finite temperature. The inclusion of the kaon loop results in a finite width of the spectrum, improving agreement with experimental data. We also investigate the spin alignment of the ϕ meson induced by its motion relative to the thermal background. In the NJL model with only chiral condensates, we find that deviations from the unpolarized limit of 1/3 are negligible.
