New results from CLAS on the ep→e'pπ⁰ beam spin asymmetry in the resonance region

The N* program in Jefferson Lab is crucial for understanding the strong interaction in the non-perturbative regime and the emergence of hadron mass.

Studies of resonance electroexcitation in Nπ electroproduction represent an important part of these efforts.

The data on beam spin asymmetry provide unique information on

the imaginary part of the interference terms between the electroproduction amplitudes with the longitudinally and transversely polarized virtual photons.

The new CLAS results on beam spin asymmetry and polarized structure function σ_LT' for π⁰p electroproduction at invariant masses of the final hadrons from the threshold and up to 1.8 GeV and at photon virtualities 0.4 GeV²<Q²<1.0 GeV² will be

presented in the talk. Analyses of these results demonstrated sensitivity of the Legendre moments of the σ_LT' structure function to the electroexcitation

amplitudes of the nucleon resonances in the mass range > 1.6 GeV.

Combined studies of beam spin asymmetries and

unpolarized cross sections for π⁰p electroproduction channel will allow us to improve knowledge on Q²-evolution of the resonance electroexcitation amplitudes,

in particular, for the resonances in the third resonance region.