Exclusive ${\pi}^0$ electroproduction at $W>2$ GeV with CLAS

Jefferson Lab-CEBAF. Exclusive neutral-pion electroproduction E- P --> E- PI0 P was measured at Jefferson Lab with the CLAS detector. The data were taken with a 5.75 GeV electron beam and a 2.5 cm-long liquid-hydrogen target. The structure functions DSIG(T)/Dt + EPSILON*DSIG(L)/Dt, DSIG(TT)/Dt and DSIG(LT)/Dt as functions of t were obtained over a wide range of Q**2 and XB. The physical significance of the structure functions is as follows: - DSIG(T)/Dt is the sum of structure functions which are initiated by a transverse virtual photon of positive and negative helicity (MU = +-1), with and without nucleon helicity flip, respectively DELTA(NU) = +- 1 and DELTA(NU) = 0. - DSIG(L)/Dt is the sum of structure functions initiated by a longitudinal virtual photon, both with and without nucleon helicity-flip, respectively DELTA(NU) = +- 1 and DELTA(NU) = 0. - EPSILON represents the ratio of fluxes of longitudinally and transversely polarized virtual photons. - DSIG(LT)/Dt corresponds to interferences involving products of amplitudes for longitudinal and transverse photons. - DSIG(TT)/Dt corresponds to interferences involving products of transverse positive and negative photon helicity amplitudes.