Light Baryon Spectroscopy – Recent Results Light Baryon Spectroscopy – Recent Results R. Beck HISKP, University Bonn IWHSS, 16. – 18.April 2012 , Lisbon Introduction Narrow structure Summary and Outlook Recent Results from ELSA, JLab and MAMI: supported by the DFG within the SFB/TR16 0 p p p p n n
Light Baryon Spectroscopy – Recent Results. R. Beck HISKP, University Bonn IWHSS, 16. – 18.April 2012 , Lisbon. Introduction. Recent Results from ELSA, JLab and MAMI:. Narrow structure. Summary and Outlook. supported by the DFG within the SFB/TR16. Introduction. - PowerPoint PPT Presentation
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established in the region 1400 MeV < W < 2000 established in the region 1400 MeV < W < 2000 MeVMeV
PDG 2010: Status on nucleon resonances
Energy pattern for the dominant states
Constituent Quark Models
Dynamical Models
Lattice QCD
Various nucleon models predict many more states
weak coupling to N final state
insufficient data base
L. Tiator
IntroductionIntroductiontalk yesterday by M. Peardon
Experimental program for N*Experimental program for N*
Precision data for different final states (pn p , K+, p....)
Common effort at ELSA, JLab and MAMI,
Polarization experiments (beam, target and recoil) “complete data base”
Xp
pp + +
+pp + +
+pp +
+pp + +pK+ +
To constrain PWA unique PWA solution
Problem with a unique PWA solution Problem with a unique PWA solution
NN
- threshold until - region
8 well chosen observable have to be measured to determine the production amplitudes (F1,F2,F3 and F4)
above - threshold
additional constraints:
(a) s- and p- wave approximation
(b) Fermi- Watson theorem
NN NN
same I, J in the final state same scattering phase IJ
two observable sufficient for “complete data base”
differential cross section : dd
beam asymmetry :
Fermi- Watson theorem not valid any more
More observable needed to get a unique partial wave solution
Partial waves for the PPartial waves for the P3333(1232) (1232)
O. Hanstein, D. Drechsel, and L. Tiator Phys. Lett. B 385, 45 (1996)R.B. and H.P. Krahn Phys. Rev. Lett. 78, 606 (1997)R.B. and H.P. Krahn Phys. Rev. C61, 035204 (2000)
Resonance parameter for the PResonance parameter for the P3333(1232) (1232)
Problem with a unique PWA solution Problem with a unique PWA solution
NN
- threshold until - region
8 well chosen observable have to be measured to determine the production amplitudes (F1,F2,F3 and F4)
above - threshold
additional constraints:
(a) s- and p- wave approximation
(b) Fermi- Watson theorem
NN NN
same I, J in the final state same scattering phase IJ
two observable sufficient for “complete data base”
differential cross section : dd
beam asymmetry :
Fermi- Watson theorem not valid any more
More observable needed to get a unique partial wave solution
Meson photoproduction
pp
Photon helicity couplings: A1/2 und A3/2
S11(1535) : A1/2 (S11(1535)) only
D13(1520) : A1/2 (D13(1520)) and A3/2(D13(1520))Total cross section: tot ~ |A1/2(S11)|2 + |A1/2(P13)|2 + |A3/2(P13)|2 + …..
V. Crede, O. Bartolomy et al., PRL 94 (2005) 012004,EPJ A33 (2007) 133
P13(1720) : A1/2 (P13(1720)) and A3/2(P13(1720))
Problem with a unique PWA solution Problem with a unique PWA solution