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Published byAnnabel Stephens Modified over 9 years ago
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Allows to address central question: “ What are the relevant degrees-of-freedom at varying distance scale ?” N π, B=N,N*, * q q q e e' ** e ** e **
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p ** N N* photocoupling amplitudes → A 1/2, A 3/2 and S 1/2 → A 1/2, A 3/2 and S 1/2 Pion electroproduction multipole amplitude → E l , M l and S l . l : the orbital angular momentum in Nπ system. ± sign : spin of proton couples to the orbital momentum. E l , M l ,S l A 1/2, A 3/2,S 1/2 S z = 1 S z = 0 S 1/2 S z = 1/2
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* Publication includes analyses of N channels
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one photon exchange approximation
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E 0 =5.499 GeV Luminosity ~20 fb -1 Kinematic binning ~ 29K cross-section data VariableRangeNumber of bin (size) W 1.6 ~2.0 GeV5(40MeV), 3(60MeV) Q2Q2 1.7 ~4.5 GeV 2 5 (vary) cos -1.0~+0.5, +0.5~+1.07 (0.2), 10 (0.05) 0 ~ 360 24 (15 ), 48(7.5 )
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Exp. e1-f A + B cos + C cos2 Overall systematic uncertainty is 9-10%
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+0.5+0.9+0.7 cosine bins +1.0 0.575 0.625 0.5250.6750.7250.7750.8250.8750.9250.975 fine cosine bins at forward angle
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Exp. e1-f DMT MAID2003 MAID2007
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Exp. e1-f ( W= 20MeV) Exp. e1-f ( Sys. Err. ) PRC 77, 015208 (2008) Exp. e1-f ( W= 40MeV)
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This analysis, I.G. Azauryan (UIM & DR) RPP (PDG) Phys. Rev. D 86 (2012) I.G. Aznauryan, Phys. Rev. C 72 (2005) Z. Lee and F. Close (1990) M. Dugger Phys. Rev. C 76 (2007) M.M. Gianini/E. Santopinto (hQCM) D. Merten, U. Loring, et al., (2003) V. I. Mokkev, I.G. Aznauryan, arXiv1310.1101 (2013)
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This analysis, I.G. Azauryan (UIM & DR) RPP (PDG) Phys. Rev. D 86 (2012) I.G. Aznauryan, Phys. Rev. C 72 (2005) Z. Lee and F. Close (1990) M.M. Gianini/E. Santopinto (hQCM) D. Merten, U. Loring, et al., (2003)
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This analysis, I.G. Azauryan (UIM & DR) RPP (PDG) Phys. Rev. D 86 (2012) B. Julia-Diaz, T.-S.H. Lee, A. Matsuyama, et al., (2008) M. Dugger Phys. Rev. C 76 (2007) M.M. Gianini/E. Santopinto (hQCM) D. Merten, U. Loring, et al., (2003)
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This analysis, I.G. Azauryan (UIM & DR) RPP (PDG) included A. Anisovich (BONN, PNPI), EPJ A48 15 (2012) M.M. Gianini/E. Santopinto (hQCM)
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Using the exclusive single positively charged pion off the proton data, the differential cross sections have been measured for high-lying resonances. (1.6 GeV< W< 2.0 GeV, 1.7 GeV 2 < Q 2 < 4.5 GeV 2 ). Preliminary results are consistent with the published data. Angular distribution at high W likely indicate the pion pole contribution. Preliminary helicity-amplitudes for F 15 (1680 ), D 15 (1675), P 11 (1710) resonances have been extracted using a UIM and DR. Combined analysis of available and future data on all exclusive meson electroproduction channels at W >1.6 GeV and at Q 2 >2.0 GeV 2 within the framework of coupled channel approaches will improve considerably our knowledge on high mass N*-state electro-couplings.
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Questions/comments ? Thank you for your attention
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This analysis Total from UIM PRC 77, 015208 (2008) Switch off (1600)P 33 and N(1720)P 13 from the UIM Switch off N(1680)F 15 from the UIM Switch off (1620)S 31 and N(1650)S 11 from the UIM Switch off all third resonances from the UIM Q 2 =1.8GeV 2 Q 2 =3.15GeV 2
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MAID 2007 (global fit) RPP (PDG) J. Phys. G 37 (2010) I.G. Aznauryan, Phys. Rev. C 72 (2005)
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