Simple s helicity structure at the nucleon-nucleon vertex of the pomeron and meson exchanges: experimental evidence and connections with duality

Abstract

Experimental evidence in favour of an almost pure s helicity non-flip character at the nucleon-nucleon vertex of the Pomeron, f O and ω exchanges is discussed. Further we discuss some connections with duality of this phenomenon and the related feature of ϱ and A 2 exchanges which present an essentially helicity flip coupling at the NN vertex.