Leptonic Decay Constants of D_(s) and B_(s) Mesons at Finite Temperature

In the present work, $D_{s}$ and $B_{s}$ meson parameters are investigated in the framework of thermal QCD sum rules. The temperature dependence of the mass and the leptonic decay constants are investigated by using Borel transform sum rules and Hilbert moment sum rules. To increase sensitivity, the vacuum contributions are subtracted from thermal expressions and the temperature dependences of the leptonic decay constants and meson masses are studied.