Study Of Masses, Decay Constants, η-η’ Mixing Of Light Pseudoscalar Mesons And Their Thermal Behaviors

Quantum Chromodynamics（QCD）is the fundamental theory to describe the strong interaction between quarks and gluons.In the low energy region,Chiral Perturbation Theory（xPT）is an important effective field theory of QCD.Chiral Perturbation Theory is a reliable tool to study the low energy dynamics of QCD and it is based on the global symmetries of QCD.Within the framework of U（3）chiral perturbation theory,we revisit the masses,de-cay constants and the mixing parameters of the light pseudoscalar mesons π,K,η and η.The low energy constants up to next-to-next-to-leading order are determined by includ-ing the light-quark mass dependences of the various quantities from different lattice QCD simulations.Then we study the finite temperature behaviors of the various quantities like mπ,mk,mη,mη and F₀,F₈,θ₀,θ₈,F_q,F_s,θ_q,θ_s.In our study we find the masses of the π,K and η are increased when increasing the temperatures,the η mass turns out to be slightly decreased in the low-temperature region.