$\hat{I}\cdot$ MAID-2015: update with new data and new resonances

Abstract

Recent data for $\hat{I}\cdot$ and $\hat{I}\cdot \prime$ photoproduction on protons obtained by the A2 Collaboration at MAMI are presented. The total cross section for $\hat{I}\cdot$ photoproduction demonstrates a cusp at the energy corresponding to the $\hat{I}\cdot \prime$ threshold. The new data and existing data from GRAAL, CBELSA/TAPS, and CLAS collaborations have been analyzed by an expansion in terms of associated Legendre polynomials. %A Legendre decomposition shows the sensitivity to small partial-wave contributions. The isobar model $\hat{I}\cdot$MAID updated with $\hat{I}\cdot \prime$ channel and new resonances have been used to fit the new data. The new solution $\hat{I}\cdot$MAID-2015 reasonably good describes the data in the photon beam energy region up to 3.7 GeV.

6 pages, 6 figures, Mini-Workshop "Exploring Hadron Resonances", Bled, Slovenia, July 5-11, 2015