Information on the structure of the rho meson from the pion form-factor - High Energy Physics - PhenomenologyReport as inadecuate




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Abstract: The electromagnetic pion form-factor is calculated in a Bethe-Salpeterapproach which accounts for pion rescattering. In the scattering kernel thepion-pion contact interaction from lowest-order chiral perturbation theory isconsidered together with an optional vector meson in the s-channel.Correspondingly the virtual photon couples to a two-pion state and optionallyto the vector meson. It is shown that for reasonable ranges of input parametersthe experimentally observed pion form-factor cannot be described by theiterated pion-pion contact interaction alone, i.e. without an elementary vectormeson. The inclusion of an elementary vector meson allows for an excellentdescription. This completes a recent study ``Information on the structure ofthe a 1 from tau decay- where it has been shown that the a 1 meson can bewell understood as a rescattering process of rho meson and pion. Here it isdemonstrated that within the same formalism the rho meson cannot be understoodas a pion-pion rescattering process. This suggests that the chiral partners a 1and rho are not only different in mass, but also different in nature.



Author: Stefan Leupold Giessen U.

Source: https://arxiv.org/



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