Abstract
We report a new measurement of the exclusive electroproduction reaction γ* p → π0 p to explore the evolution from soft non‐perturbative physics to hard processes via the Q2 dependence of the magnetic (M1+), electric (E1+) and scalar (S1+) multipoles in the N → Δ transition. 9000 differential cross section data points cover W from threshold to 1.4 GeV/c2, 4π center‐of‐mass solid angle, and Q2 from 3 to 6 GeV2/c2, the highest yet achieved. It is found that the magnetic form factor GM* decreases with Q2 more steeply than the proton magnetic form factor, the ratio E1+/M1+ is small and negative, indicating strong helicity non‐conservation, and the ratio S1+/M1+ is negative, while its magnitude increases with Q2.
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