Axial anomaly and the delta_{LT} puzzle

Abstract

The axial anomaly contribution to generalized longitudinal-transverse polarizability ${\delta }_{LT}^{}$ is calculated within Regge approach. It is shown that the contribution from the exchange of the $a_1^{}(1260)$ Regge trajectory is nontrivial and might have the key role to explain the large difference between the predictions of chiral perturbation theory and the experimental data for the neutron ${\delta }_{LT}^{}$. We also present the prediction for the proton ${\delta }_{LT}^{}$, which will be measured at the Thomas Jefferson National Accelerator Facility in near future.

Comments: 5 pages, 3 figures, REVTeX, to be published in Phys. Rev. D