Abstract
Photoproduction of π0π±-pairs from quasifree nucleons bound in the deuteron has been investigated to study the helicity dependence of this reaction. Measurements with a liquid deuterium target were used to extract the unpolarized cross sections for reactions on protons and neutrons. A deuterated, longitudinally polarized solid-butanol target, together with a circularly polarized photon beam, determined the double polarization observable E. From these results the spin-dependent cross sections σ1/2 and σ3/2, corresponding to the anti-parallel and parallel spin configurations of the beam photon and target nucleon, have been derived. The measurements were performed at the Mainz MAMI accelerator with tagged, circularly-polarized photon beams produced via bremsstrahlung from longitudinally polarized electron beams. The reaction products were detected with an almost 4π solid-angle covering calorimeter composed of the Crystal Ball and TAPS detectors, supplemented by plastic scintillation detectors for charged particle identification. The results are sensitive to sequential decays of nucleon resonances via intermediate states and also to the decay of nucleon resonances by emission of charged ρ mesons, and are compared to recent model results.
| Original language | English |
|---|---|
| Article number | 138273 |
| Number of pages | 8 |
| Journal | Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics |
| Volume | 847 |
| Early online date | 27 Oct 2023 |
| DOIs | |
| Publication status | Published - 10 Dec 2023 |
Bibliographical note
Funding Information:We wish to acknowledge the outstanding support of the accelerator group and operators of MAMI. This work was supported by Schweizerischer Nationalfonds (200020-156983, 132799, 121781, 117601), Deutsche Forschungsgemeinschaft (SFB 443, SFB 1044, SFB/TR16), the INFN-Italy, the European Community-Research Infrastructure Activity under FP7 programme (Hadron Physics, grant agreement No. 227431), the UK Science and Technology Facilities Council (ST/J000175/1, ST/G008604/1, ST/G008582/1, ST/J00006X/1, and ST/L00478X/1), the Natural Sciences and Engineering Research Council of Canada (NSERC, FRN: SAPPJ-2015-00023), Canada. The model calculation was supported by the Russian Science Foundation, Grant No. 22-42-04401. This material is based upon work also supported by the U.S. Department of Energy Office of Science, Office of Nuclear Physics Research Division, under Award Numbers DE-FG02-99-ER41110, DE-FG02-88ER40415, DE-FG02-01-ER41194, and DE-SC0014323 and by the National Science Foundation, under Grant Nos. PHY-1039130 and IIA-1358175.
Funding Information:
We wish to acknowledge the outstanding support of the accelerator group and operators of MAMI. This work was supported by Schweizerischer Nationalfonds ( 200020-156983 , 132799 , 121781 , 117601 ), Deutsche Forschungsgemeinschaft ( SFB 443 , SFB 1044 , SFB/TR16 ), the INFN -Italy, the European Community-Research Infrastructure Activity under FP7 programme (Hadron Physics, grant agreement No. 227431 ), the UK Science and Technology Facilities Council ( ST/J000175/1 , ST/G008604/1 , ST/G008582/1 , ST/J00006X/1 , and ST/L00478X/1 ), the Natural Sciences and Engineering Research Council of Canada (NSERC, FRN: SAPPJ-2015-00023 ), Canada. The model calculation was supported by the Russian Science Foundation , Grant No. 22-42-04401 . This material is based upon work also supported by the U.S. Department of Energy Office of Science , Office of Nuclear Physics Research Division, under Award Numbers DE-FG02-99-ER41110 , DE-FG02-88ER40415 , DE-FG02-01-ER41194 , and DE-SC0014323 and by the National Science Foundation , under Grant Nos. PHY-1039130 and IIA-1358175 .
Publisher Copyright:
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