Finite-energy sum rules in eta photoproduction off a nucleon

Abstract

The reaction γN → ηN is studied in the high-energy regime (with photon lab energies E lab γ > 4 GeV) using information from the resonance region through the use of finite-energy sum rules (FESR). We illustrate how analyticity allows one to map the t-dependence of the unknown Regge residue functions. We provide predictions for the energy dependence of the beam asymmetry at high energies.

Measurement of the beam asymmetry Σ for π0 and η photoproduction on the proton at EγGhoul1, Anassontzis2, Austregesilo3 et al. 2017Phys. Rev. CSelf Cite685810View full textAdd to dashboardCite

“…6 for comparison [4][5][6][7][8][9]. Some of these calculations incorporate a significant dip in the asymmetries near −t = 0.5 (GeV/c) 2 , due to a contribution from the axial-vector Reggeon exchange that is consistent with previous π 0 measurements at E γ = 10 GeV from SLAC [19].…”

“…Similar approaches addressing both π 0 and η photoproduction have been developed and extended recently by several groups, including Laget [5,6], the JPAC collaboration [7,8], and Donnachie and Kalashnikova [9]. Predictions for the linearly polarized beam asymmetry are sensitive to the relative contribution from vector and axial-vector exchanges, and new data can provide important constraints to better understand this production mechanism.…”

Electroweak single-pion production off the nucleon: From threshold to high invariant masses

“…IV into a hybrid model, that can be applied over the entire W region of interest for present and future accelerator-based neutrino experiments. Similar approaches have previously been proposed in the literature in different contexts [68][69][70][71]. In particular, the so-called Regge-plus-resonance (RPR) model developed by the Ghent group was used with remarkable success in photoproduction of strange hadrons [72][73][74].…”

Model selection for pion photoproduction

“…At high energies, Regge parametrizations are very effective [60,61]. Formulations to provide amplitudes that cover the entire energy region from threshold to the highest energies are under development [62,63]. Yet, sometimes partial waves are parameterized purely phenomenologically in terms of functions that are in agreement with basic S-matrix principles such as coupled-channel two-body unitarity, the correct threshold behavior or Fermi-Watson's theorem [64,65], but that are otherwise left free to ensure a high degree of model independence as in the SAID approach [57].…”