A note on the tensor and vector exchange contributions to KK¯→KK¯,DD¯→DD¯ and π+π-→π+π- reactions.

In this note we study the tensor and vector exchange contributions to the elastic reactions involving the pseudoscalars mesons π + π - , K + K - and D + D - . In the case of the tensor-exchange contributions we assume that an intermediate tensor f 2 (1270) is dynamically generated from the interaction of two virtual ρ mesons, with the use of a pole approximation. The calculation of the two-loop amplitude is facilitated since the triangle loops can be factorized and computed separately. The results show very small contributions coming from the tensor-exchange mechanisms when compared with those from the vector-exchange processes. We compare our results for π π and K K ¯ scattering with those obtained in other works where the f 2 (1270) is considered as an ordinary q q ¯ meson. Our picture provides a smaller contribution but of similar order of magnitude for pion scattering and stabilizes the results in the case of K K ¯ , allowing us to make estimates for D D ¯ scattering. [ABSTRACT FROM AUTHOR]