Pomeranchuk's theorem
Pomeranchuk's theorem, named after Soviet physicist Isaak Pomeranchuk, states that difference of cross sections of interactions of elementary particles κ 1 + κ 2 {\displaystyle \kappa _{1}+\kappa _{2}} and κ 1 + κ 2 ¯ {\displaystyle \kappa _{1}+{\bar {\kappa _{2}}}} (i. e.