Single [Formula: see text] production off neutrons bound in deuteron with linearly polarized photons

C Mullen; S Gardner; D I Glazier; S J D Kay; K Livingston; I I Strakovsky; R L Workman; S Abt; P Achenbach; F Afzal; Z Ahmed; C S Akondi; J R M Annand; M Bashkanov; R Beck; M Biroth; N S Borisov; A Braghieri; W J Briscoe; F Cividini; C Collicott; S Costanza; A Denig; M Dieterle; E J Downie; P Drexler; S Fegan; M I Ferretti-Bondy; D Ghosal; I Gorodnov; W Gradl; M Günther; G Gurevic; L Heijkenskjöld; D Hornidge; G M Huber; N Jermann; A Kaeser; M Korolija; V L Kashevarov; B Krusche; V V Kulikov; A Lazarev; S Lutterer; I J D MacGregor; D M Manley; P P Martel; M A Martemianov; C Meier; R Miskimen; M Mocanu; E Mornacchi; A Neganov; M Oberle; M Ostrick; P Otte; D Paudyal; P Pedroni; A Powell; S N Prakhov; G Reicherz; G Ron; T Rostomyan; C Sfienti; V Sokhoyan; K Spieker; O Steffen; Th Strub; I Supek; A Thiel; M Thiel; A Thomas; M Unverzagt; Yu A Usov; S Wagner; N K Walford; D P Watts; D Werthmüller; J Wettig; L Witthauer; M Wolfes; N Zachariou; (A2 Collaboration at MAMI)

doi:10.1140/epja/s10050-021-00521-9

Single $π^{0}$ production off neutrons bound in deuteron with linearly polarized photons

Eur Phys J A Hadron Nucl. 2021;57(6):205. doi: 10.1140/epja/s10050-021-00521-9. Epub 2021 Jun 26.

Authors

C Mullen¹, S Gardner¹, D I Glazier¹, S J D Kay^{2

3}, K Livingston¹, I I Strakovsky⁴, R L Workman⁴, S Abt⁵, P Achenbach⁶, F Afzal⁷, Z Ahmed³, C S Akondi⁸, J R M Annand¹, M Bashkanov⁹, R Beck⁷, M Biroth⁶, N S Borisov¹⁰, A Braghieri¹¹, W J Briscoe⁴, F Cividini⁶, C Collicott⁶, S Costanza¹¹, A Denig⁶, M Dieterle⁵, E J Downie⁴, P Drexler⁶, S Fegan⁹, M I Ferretti-Bondy⁶, D Ghosal⁵, I Gorodnov¹⁰, W Gradl⁶, M Günther⁵, G Gurevic¹², L Heijkenskjöld⁶, D Hornidge¹³, G M Huber³, N Jermann⁵, A Kaeser⁵, M Korolija¹⁴, V L Kashevarov^{6

10}, B Krusche⁵, V V Kulikov¹⁵, A Lazarev⁷, S Lutterer⁵, I J D MacGregor¹, D M Manley⁸, P P Martel⁶, M A Martemianov¹⁵, C Meier⁵, R Miskimen¹⁶, M Mocanu⁹, E Mornacchi⁶, A Neganov¹⁰, M Oberle⁵, M Ostrick⁶, P Otte⁶, D Paudyal³, P Pedroni¹¹, A Powell¹, S N Prakhov⁶, G Reicherz¹⁷, G Ron¹⁸, T Rostomyan⁵, C Sfienti⁶, V Sokhoyan⁶, K Spieker⁷, O Steffen⁶, Th Strub⁵, I Supek¹⁴, A Thiel⁷, M Thiel⁶, A Thomas⁶, M Unverzagt⁶, Yu A Usov¹⁰, S Wagner⁶, N K Walford⁵, D P Watts⁹, D Werthmüller¹, J Wettig⁶, L Witthauer⁵, M Wolfes⁶, N Zachariou⁹; (A2 Collaboration at MAMI)

Affiliations

¹ SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ UK.
² SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh, EH9 3FD UK.
³ Department of Physics, University of Regina, Regina, SK S4S 0A2 Canada.
⁴ Department of Physics, Institute for Nuclear Studies, The George Washington University, Washington, DC, 20052 USA.
⁵ Institut für Physik, University of Basel, 4056 Basel, Switzerland.
⁶ Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany.
⁷ Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, 53115 Bonn, Germany.
⁸ Kent State University, Kent, OH 44242 USA.
⁹ Department of Physics, University of York, Heslington, York, Y010 5DD UK.
¹⁰ JINR, 141980 Dubna, Russia.
¹¹ INFN Sezione di Pavia, 27100 Pavia, Italy.
¹² Institute for Nuclear Research, 125047 Moscow, Russia.
¹³ Mount Allison University, Sackville, NB E4L3B5 Canada.
¹⁴ Rudjer Boskovic Institute, 10000 Zagreb, Croatia.
¹⁵ NRC "Kurchatov Institute"-ITEP, 117218 Moscow, Russia.
¹⁶ University of Massachusetts, Amherst, MA 01003 USA.
¹⁷ Institut für Experimentalphysik, Ruhr-University of Bochum, 44801 Bochum, Germany.
¹⁸ Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem, Israel.

Abstract

The quasifree $\vec{γ} d \to π^{0} n (p)$ photon beam asymmetry, $Σ$ , has been measured at photon energies, $E_{γ}$ , from 390 to 610 MeV, corresponding to center of mass energy from 1.271 to 1.424 GeV, for the first time. The data were collected in the A2 hall of the MAMI electron beam facility with the Crystal Ball and TAPS calorimeters covering pion center-of-mass angles from 49 $^{\circ}$ to 148 $^{\circ}$ . In this kinematic region, polarization observables are sensitive to contributions from the $Δ (1232)$ and N(1440) resonances. The extracted values of $Σ$ have been compared to predictions based on partial-wave analyses (PWAs) of the existing pion photoproduction database. Our comparison includes the SAID, MAID and Bonn-Gatchina analyses; while a revised SAID fit, including the new $Σ$ measurements, has also been performed. In addition, isospin symmetry is examined as a way to predict $π^{0} n$ photoproduction observables, based on fits to published data in the channels $π^{0} p$ , $π^{+} n$ and $π^{-} p$ .