PT Journal
AU Wang, YF
   Yao, DL
   Zheng, HQ
TI New insights on low energy pi N scattering amplitudes: comprehensive analyses at O (p(3)) level
SO Chinese Physics C
JI Chin. Phys. C
PY 2019
BP 064110
EP 22pp
VL 43
IS 6
DI 10.1088/1674-1137/43/6/064110
LA English
DE dispersion relations; pion-nucleon scattering; chiral perturbation theory
AB A production representation of partial-wave S matrix is utilized to construct low-energy elastic pion-nucleon scattering amplitudes from cuts and poles on complex Riemann sheets. Among them, the contribution of left-hand cuts is estimated using the O (p(3)) results obtained in covariant baryon chiral perturbation theory within the extendedon-nass-shell scheme. By fitting to data on partial-wave phase shifts, it is indicated that the existences of hidden poles in S-11 and P-11 channels, as conjectured in our previous paper [Eur. Phys. J. C, 78(7): 543 (2018)], are firmly established. Specifically, the pole mass of the S-11 hidden resonance is determined to be (895 +/- 81)-(164 +/- 23)i MeV, whereas, the virtual pole in the P-11 channel locates at (966 +/- 18) MeV. It is found that analyses at the O (p(3)) level improves significantly the fit quality, comparing with the previous O (p(2)) one. Quantitative studies with cautious physical discussions are also conducted for the other S- and P-wave channels.
ER