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Title: Threshold π0 Photoproduction on Transverse Polarised Protons at MAMI

Polarisation-dependent differential cross sections σT associated with the target asymmetry T have been measured for the reaction γ p-→ p π0 with transverse target polarisation from π0 threshold up to photon energies of 190 MeV. Additionally, the data were obtained using a frozen-spin butanol target with the Crystal Ball / TAPS detector set-up and the Glasgow photon tagging system at the Mainz Microtron MAMI. Our results for σT have been used in combination with our previous measurements of the unpolarised cross section σ0 and the beam asymmetry Σ for a model-independent determination of S and P wave multipoles in the π0 threshold region, which includes for the first time a direct determination of the imaginary part of the E0+ multipole.
  1. Johannes Gutenberg Univ., Mainz (Germany); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). et al.
Publication Date:
Report Number(s):
JLAB-THY-15-2023; DOE/OR/23177-3327
Journal ID: ISSN 0370-2693; PII: S0370269315006905
Grant/Contract Number:
SFB 443; SFB 1044; 227431; AC05-06OR23177; FG02-01ER41194; 57071/1; 50727/1; 825
Published Article
Journal Name:
Physics Letters. Section B
Additional Journal Information:
Journal Volume: 750; Journal Issue: C; Journal ID: ISSN 0370-2693
Research Org:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
Contributing Orgs:
A2 Collaboration at MAMI
Country of Publication:
United States
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; threshold π0 photoproduction; target asymmetry; electromagnetic multipoles; chiral perturbation-theory; neutral pion-photoproduction; photon spectrometer; near-threshold; scattering; microtron; unitary; taps
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1222200; OSTI ID: 1315396