Sensitivity of tensor analyzing power in the process d+p -> d+X to the longitudinal isoscalar form factor of the Roper resonance electroexcitation

The tensor analyzing power of the process d + p --> d + X, for forward deut eron scattering in the momentum interval 3.7 to 9 GeV/c, is studied in the framework of omega exchange in an algebraic collective model for the electr oexcitation of nucleon resonances. We point out a special sensitivity of th e tensor analyzing power to the isoscalar longitudinal form factor of the R oper resonance excitation. The main argument is that the S-11(1535), D-13(1 520), and S-11(1650) resonances have only isovector longitudinal form facto rs. It is the longitudinal form factor of the Roper excitation, which plays an important role in the t dependence of the tensor analyzing power. We di scuss possible evidence of swelling of hadrons with increasing excitation e nergy. [S0556-2813(99)01303-5].