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Title: Threshold π 0 Photoproduction on Transverse Polarised Protons at MAMI

Polarisation-dependent differential cross sections σ T associated with the target asymmetry T have been measured for the reaction γ p -→ p π 0 with transverse target polarisation from π 0 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 σ T have been used in combination with our previous measurements of the unpolarised cross section σ 0 and the beam asymmetry Σ for a model-independent determination of S and P wave multipoles in the π 0 threshold region, which includes for the first time a direct determination of the imaginary part of the E 0+ 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