Pole positions and residues from pion photoproduction using the Laurent-Pietarinen expansion method

Weappliedanewapproachtodeterminethepolepositionsandresiduesfrompionphotoproductionmultipoles. The method is based on a Laurent expansion of the partial-wave T matrices, with a Pietarinen series representing the regular part of energy-dependent and single-energy photoproduction solutions. The method is applied to multipole fits generated by the MAID and George Washington University SAID (GWU-SAID) groups. We show that the number and properties of poles extracted from photoproduction data correspond very well to results from πN elastic data and values cited by the Particle Data Group (PDG). The photoproduction residues provide new information for the electromagnetic current at the pole position, which are independent of background parametrizations, which is not the case for the Breit-Wigner representation. Finally, we present the photodecay amplitudes from the current MAID and SAID solutions at the pole for all four-star nucleon resonances below W = 2 GeV.

[1]  J. Rademacker,et al.  Analysis Tools for Next-Generation Hadron Spectroscopy Experiments , 2014, 1412.6393.

[2]  A. Švarc,et al.  Poles of Karlsruhe-Helsinki KH80 and KA84 solutions extracted by using the Laurent-Pietarinen method , 2014, 1401.1947.

[3]  R. Workman,et al.  Introducing the Pietarinen expansion method into the single-channel pole extraction problem , 2013, 1307.4613.

[4]  T. Sato,et al.  Nucleon resonances within a dynamical coupled-channels model of $\pi N$ and $\gamma N$ reactions , 2013, 1305.4351.

[5]  R. Workman,et al.  Baryon photo-decay amplitudes at the pole , 2013, 1304.4029.

[6]  R. Workman,et al.  Parameterization dependence of T matrix poles and eigenphases from a fit to $\pi$N elastic scattering data , 2012, 1204.2277.

[7]  E. Klempt,et al.  Properties of baryon resonances from a multichannel partial wave analysis , 2011, 1112.4937.

[8]  C. Hanhart,et al.  Relevance of complex branch points for partial wave analysis , 2011, 1104.3490.

[9]  R. Workman,et al.  Model dependence of single-energy fits to pion photoproduction data , 2011, The European Physical Journal A.

[10]  G. Paz,et al.  Model-independent extraction of the proton charge radius from electron scattering , 2010, 1008.4619.

[11]  L. Tiator,et al.  Singularity structure of the pi N scattering amplitude in a meson-exchange model up to energies W < 2.0 GeV , 2010, 1007.2126.

[12]  B. Juliá-Díaz,et al.  Dynamical coupled-channels analysis of {sup 1}H(e,e{prime}{pi})N reactions. , 2009, 0904.1918.

[13]  C. Hanhart,et al.  Analytic properties of the scattering amplitude and resonances parameters in a meson exchange model , 2009, 0903.4337.

[14]  V. Gribov.  Strong Interactions of Hadrons at High Energies , 2008 .

[15]  S. Ceci,et al.  Resolution of the multichannel anomaly in the extraction of S-matrix resonance-pole parameters , 2008 .

[16]  M. Nowakowski,et al.  Analysis of averaged multichannel delay times , 2008, 0805.0608.

[17]  V. Gribov.  Strong Interactions of Hadrons at High Energies: References , 2008 .

[18]  L. Tiator,et al.  Unitary isobar model --MAID2007 , 2007, 0710.0306.

[19]  R. Workman,et al.  Extended partial-wave analysis of piN scattering data , 2006, nucl-th/0605082.

[20]  R. Workman,et al.  Stability of the E2/M1 ratio at the {bold {ital T}}-matrix pole , 1998, nucl-th/9809049.

[21]  I. Šlaus,et al.  The New Determination of the ηN S-wave Scattering Length From a Three-Channel, Multi-Resonance Amplitude Analysis , 1998 .

[22]  L. Tiator,et al.  The position and the residues of the delta resonance pole in pion photoproduction , 1996, nucl-th/9605008.

[23]  Nefkens,et al.  π N →η N and η N →η N partial-wave T matrices in a coupled, three-channel model , 1995, nucl-th/9501011.

[24]  Boyd,et al.  Constraints on form factors for exclusive semileptonic heavy to light meson decays. , 1994, Physical review letters.

[25]  R. Hendrick,et al.  Pion - Nucleon Partial Wave Amplitudes , 1979 .

[26]  E. Pietarinen.  Dispersion relations and experimental data , 1972 .

[27]  D. Lichtenberg,et al.  Pion-nucleon scattering , 1969 .

[28]  G. Shaw,et al.  Pion-nucleon scattering , 1969 .

[29]  S. Ciulli,et al.  On the extrapolation of the experimental scattering amplitude to the spectral function region , 1962 .

[30]  S. Ciulli,et al.  A CONVERGENT SET OF INTEGRAL EQUATIONS FOR SINGLET PROTON-PROTON SCATTERING , 1961 .

[31]  S. Mandelstam,et al.  Theory of the low-energy pion-pion interaction — II , 1960 .