Physics Letters B (Jul 2017)
First measurement of the polarization observable E and helicity-dependent cross sections in single π0 photoproduction from quasi-free nucleons
- M. Dieterle,
- L. Witthauer,
- F. Cividini,
- S. Abt,
- P. Achenbach,
- P. Adlarson,
- F. Afzal,
- Z. Ahmed,
- C.S. Akondi,
- J.R.M. Annand,
- H.J. Arends,
- M. Bashkanov,
- R. Beck,
- M. Biroth,
- N.S. Borisov,
- A. Braghieri,
- W.J. Briscoe,
- S. Costanza,
- C. Collicott,
- A. Denig,
- E.J. Downie,
- P. Drexler,
- M.I. Ferretti-Bondy,
- S. Gardner,
- S. Garni,
- D.I. Glazier,
- D. Glowa,
- W. Gradl,
- M. Günther,
- G.M. Gurevich,
- D. Hamilton,
- D. Hornidge,
- G.M. Huber,
- A. Käser,
- V.L. Kashevarov,
- S. Kay,
- I. Keshelashvili,
- R. Kondratiev,
- M. Korolija,
- B. Krusche,
- A.B. Lazarev,
- J.M. Linturi,
- V. Lisin,
- K. Livingston,
- S. Lutterer,
- I.J.D. MacGregor,
- J. Mancell,
- D.M. Manley,
- P.P. Martel,
- V. Metag,
- W. Meyer,
- R. Miskimen,
- E. Mornacchi,
- A. Mushkarenkov,
- A.B. Neganov,
- A. Neiser,
- M. Oberle,
- M. Ostrick,
- P.B. Otte,
- D. Paudyal,
- P. Pedroni,
- A. Polonski,
- S.N. Prakhov,
- A. Rajabi,
- G. Reicherz,
- G. Ron,
- T. Rostomyan,
- A. Sarty,
- C. Sfienti,
- M.H. Sikora,
- V. Sokhoyan,
- K. Spieker,
- O. Steffen,
- I.I. Strakovsky,
- 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,
- M. Wolfes,
- L. Zana
Affiliations
- M. Dieterle
- Department of Physics, University of Basel, Basel, Switzerland
- L. Witthauer
- Department of Physics, University of Basel, Basel, Switzerland
- F. Cividini
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- S. Abt
- Department of Physics, University of Basel, Basel, Switzerland
- P. Achenbach
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- P. Adlarson
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- F. Afzal
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Bonn, Germany
- Z. Ahmed
- University of Regina, Regina, SK S4S 0A2, Canada
- C.S. Akondi
- Kent State University, Kent, OH, USA
- J.R.M. Annand
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
- H.J. Arends
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- M. Bashkanov
- SUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, UK
- R. Beck
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Bonn, Germany
- M. Biroth
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- N.S. Borisov
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
- A. Braghieri
- INFN Sezione di Pavia, Pavia, Italy
- W.J. Briscoe
- Center for Nuclear Studies, The George Washington University, Washington, DC, USA
- S. Costanza
- INFN Sezione di Pavia, Pavia, Italy
- C. Collicott
- Department of Astronomy and Physics, Saint Marys University, Halifax, Canada
- A. Denig
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- E.J. Downie
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- P. Drexler
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- M.I. Ferretti-Bondy
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- S. Gardner
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
- S. Garni
- Department of Physics, University of Basel, Basel, Switzerland
- D.I. Glazier
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
- D. Glowa
- SUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, UK
- W. Gradl
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- M. Günther
- Department of Physics, University of Basel, Basel, Switzerland
- G.M. Gurevich
- Institute for Nuclear Research, Moscow, Russia
- D. Hamilton
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
- D. Hornidge
- Mount Allison University, Sackville, New Brunswick E4L 1E6, Canada
- G.M. Huber
- University of Regina, Regina, SK S4S 0A2, Canada
- A. Käser
- Department of Physics, University of Basel, Basel, Switzerland
- V.L. Kashevarov
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- S. Kay
- SUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, UK
- I. Keshelashvili
- Department of Physics, University of Basel, Basel, Switzerland
- R. Kondratiev
- Institute for Nuclear Research, Moscow, Russia
- M. Korolija
- Rudjer Boskovic Institute, Zagreb, Croatia
- B. Krusche
- Department of Physics, University of Basel, Basel, Switzerland
- A.B. Lazarev
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
- J.M. Linturi
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- V. Lisin
- Institute for Nuclear Research, Moscow, Russia
- K. Livingston
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
- S. Lutterer
- Department of Physics, University of Basel, Basel, Switzerland
- I.J.D. MacGregor
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
- J. Mancell
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
- D.M. Manley
- Kent State University, Kent, OH, USA
- P.P. Martel
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- V. Metag
- II. Physikalisches Institut, University of Giessen, Germany
- W. Meyer
- Institut für Experimentalphysik, Ruhr Universität, 44780 Bochum, Germany
- R. Miskimen
- University of Massachusetts Amherst, Amherst, MA 01003, USA
- E. Mornacchi
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- A. Mushkarenkov
- Institute for Nuclear Research, Moscow, Russia
- A.B. Neganov
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
- A. Neiser
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- M. Oberle
- Department of Physics, University of Basel, Basel, Switzerland
- M. Ostrick
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- P.B. Otte
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- D. Paudyal
- University of Regina, Regina, SK S4S 0A2, Canada
- P. Pedroni
- INFN Sezione di Pavia, Pavia, Italy
- A. Polonski
- Institute for Nuclear Research, Moscow, Russia
- S.N. Prakhov
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- A. Rajabi
- University of Massachusetts Amherst, Amherst, MA 01003, USA
- G. Reicherz
- Institut für Experimentalphysik, Ruhr Universität, 44780 Bochum, Germany
- G. Ron
- Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904, Israel
- T. Rostomyan
- Department of Physics, University of Basel, Basel, Switzerland
- A. Sarty
- Department of Astronomy and Physics, Saint Marys University, Halifax, Canada
- C. Sfienti
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- M.H. Sikora
- SUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, UK
- V. Sokhoyan
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- K. Spieker
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Bonn, Germany
- O. Steffen
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- I.I. Strakovsky
- Center for Nuclear Studies, The George Washington University, Washington, DC, USA
- Th. Strub
- Department of Physics, University of Basel, Basel, Switzerland
- I. Supek
- Rudjer Boskovic Institute, Zagreb, Croatia
- A. Thiel
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Bonn, Germany
- M. Thiel
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- A. Thomas
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- M. Unverzagt
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- Yu.A. Usov
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
- S. Wagner
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- N.K. Walford
- Department of Physics, University of Basel, Basel, Switzerland
- D.P. Watts
- SUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, UK
- D. Werthmüller
- Department of Physics, University of Basel, Basel, Switzerland
- J. Wettig
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- M. Wolfes
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- L. Zana
- SUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, UK
- DOI
- https://doi.org/10.1016/j.physletb.2017.04.079
- Journal volume & issue
-
Vol. 770,
no. C
pp. 523 – 531
Abstract
The double-polarization observable E and the helicity-dependent cross sections σ1/2 and σ3/2 have been measured for the first time for single π0 photoproduction from protons and neutrons bound in the deuteron at the electron accelerator facility MAMI in Mainz, Germany. The experiment used a circularly polarized photon beam and a longitudinally polarized deuterated butanol target. The reaction products, recoil nucleons and decay photons from the π0 meson were detected with the Crystal Ball and TAPS electromagnetic calorimeters. Effects from nuclear Fermi motion were removed by a kinematic reconstruction of the π0N final state. A comparison to data measured with a free proton target showed that the absolute scale of the cross sections is significantly modified by nuclear final-state interaction (FSI) effects. However, there is no significant effect on the asymmetry E since the σ1/2 and σ3/2 components appear to be influenced in a similar way. Thus, the best approximation of the two helicity-dependent cross sections for the free neutron is obtained by combining the asymmetry E measured with quasi-free neutrons and the unpolarized cross section corrected for FSI effects under the assumption that the FSI effects are similar for neutrons and protons.
