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Observation of the p η ′ Cusp in the New Precise Beam Asymmetry Σ Data for γ p → p η
- Source :
- Physical review letters 125(15), 152002 (2020). doi:10.1103/PhysRevLett.125.152002
- Publication Year :
- 2020
- Publisher :
- APS, 2020.
-
Abstract
- Data on the beam asymmetry Σ in the photoproduction of η mesons off protons are reported for tagged photon energies from 1130 to 1790 MeV (mass range from W=1748 MeV to W=2045 MeV). The data cover the full solid angle that allows for a precise moment analysis. For the first time, a strong cusp effect in a polarization observable has been observed that is an effect of a branch-point singularity at the pη^{'} threshold [E_{γ}=1447 MeV (W=1896 MeV)]. The latest BnGa partial wave analysis includes the new beam asymmetry data and yields a strong indication for the N(1895)1/2^{-} nucleon resonance, demonstrating the importance of including all singularities for a correct determination of partial waves and resonance parameters.
- Subjects :
- Nuclear Theory
Physics::Accelerator Physics
ddc:530
Nuclear Experiment
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- Physical review letters 125(15), 152002 (2020). doi:10.1103/PhysRevLett.125.152002
- Accession number :
- edsair.pmid.dedup....08a78950233393b7b6a3f22dac0aa8d2