Kbar{K} Threshold Phenomena, f₀-a₀ Interference and Kaonium Production

We develop a new formalism to study $K\bar{K}$ threshold phenomena with resonances $f_0$, $a_0$ and $K^+K^-$ atom (kaonium) included. The approach provides two possible scenarios for $f_0-a_0$ mixing. Drastic interference patterns can be observed in $K^+K^-$electroproduction at CEBAF, $pd\to ~^3HeX$ reaction, and $N\bar N$ annihilation.