Anomalous t-dependence in diffractive electroproduction of 2S radially excited light vector mesons at HERA

Within the color dipole gBFKL phenomenology of the diffraction slope we predict an anomalous t-dependence of the differential cross section as a function of energy and for the production of radially excited light vector mesons. The pattern we found for the t-dependence for is in contradiction with the well-known standard monotonical t-behavior for theV(1S) vector mesons. The origin of this phenomenon lies in the interplay of the nodal structure of the V'(2S) radial wave function and the energy and dipole size dependence of the color dipole cross section and the diffraction slope. We show how a different position of the node in the V'(2S) wave function leads to a different pattern of anomalous t-behavior of and discuss the possibility to determine this position from the low energy and HERA data. Received: 5 September 2000 / Revised version: 24 November 2000 / Published online: 23 January 2001