Exclusive production of $π^+ π^-$ pairs in diffractive $γp$ and in $pp$ collisions within the tensor-pomeron approach

We discuss exclusive production of $π^+ π^-$ pairs in diffractive $γp$ and in $pp$ collisions at high energies, considering resonant ($ρ(770)$, $ω$, $f_2(1270)$) and non-resonant (Drell-Söding) contributions within the tensor-pomeron approach. For the $γp \to π^+ π^- p$ reaction, the model describes