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Title: Cross section for γ n π 0 n measured at the Mainz A2 experiment

Journal Article · · Physical Review C

The γ n → π 0 n differential cross section evaluated for 27 energy bins span the photon-energy range 290– 813 MeV (W = 1.195–1.553 GeV) and the pion c.m. polar production angles, ranging from 18° to 162°, making use of model-dependent nuclear corrections to extract π0 production data on the neutron from measurements on the deuteron target. Additionally, the total photoabsorption cross section was measured. The tagged photon beam produced by the 883 MeV electron beam of the Mainz Microtron MAMI was used for the π0-meson production. Our accumulation of 3.6 × 106 γ n → π 0 n events allowed a detailed study of the reaction dynamics. Our data are in reasonable agreement with previous A2 measurements and extend them to lower energies. The data are compared with predictions of previous SAID, MAID, and BnGa partial-wave analyses and to the latest SAID fit MA19 that included our data. Selected photon-decay amplitudes N * → γ n at the resonance poles are determined for the first time.

Research Organization:
Kent State Univ., Kent, OH (United States); George Washington Univ., Washington, DC (United States); Univ. of Massachusetts, Amherst, MA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Nuclear Physics (NP); German Research Foundation (DFG); Schweizerischer Nationalfonds; UK Science and Technology Facilities Council (STFC); Russian Foundation for Basic Research (RFBR); National Science Foundation (NSF)
Contributing Organization:
A2 Collaboration at MAMI
Grant/Contract Number:
SC0014323; FG02-01ER41194; SC0016583; SC0016582; FG02-88ER40415
OSTI ID:
1578073
Alternate ID(s):
OSTI ID: 1659121
Journal Information:
Physical Review C, Vol. 100, Issue 6; ISSN 2469-9985
Publisher:
American Physical Society (APS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 18 works
Citation information provided by
Web of Science

References (64)

Evaluation of the γ n π p differential cross section in the Δ -isobar region journal December 2012
Unitary isobar model --MAID2007 journal October 2007
Quasifree photoproduction of η mesons off protons and neutrons journal July 2014
Design of a tagged photon spectrometer for use with the Mainz 840 MeV microtron
  • Anthony, I.; Kellie, J. D.; Hall, S. J.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 301, Issue 2 https://doi.org/10.1016/0168-9002(91)90464-2
journal March 1991
Measurement of the H 1 ( γ⃗ , p⃗ ) π 0 Reaction Using a Novel Nucleon Spin Polarimeter journal January 2014
Total photoabsorption cross section for 4 He from 200 to 800 MeV journal March 1997
Scrutinizing the evidence for N ( 1685 ) journal March 2017
Review of Particle Physics text January 2008
Accurate Test of Chiral Dynamics in the γ p π 0 p Reaction journal August 2013
Updated analysis of N N elastic scattering to 3 GeV journal August 2007
Photoproduction of π 0 Mesons off Neutrons in the Nucleon Resonance Region journal April 2014
Pole positions and residues from pion photoproduction using the Laurent-Pietarinen expansion method journal June 2014
Parameterization dependence of T -matrix poles and eigenphases from a fit to π N elastic scattering data journal September 2012
Neutron Detection in the A2 Collaboration Experiment on Neutral Pion Photo-production on Neutron journal April 2018
Review of Particle Physics journal August 2018
Extracting the photoproduction cross sections off the neutron, via the γ n π p reaction, from deuteron data with final-state interaction effects journal September 2011
The Effect of Final State Interactions on Reaction Cross Sections journal December 1952
Introducing the Pietarinen expansion method into the single-channel pole extraction problem journal September 2013
Upgrade of the Glasgow photon tagging spectrometer for Mainz MAMI-C journal June 2008
Baryon photo-decay amplitudes at the pole journal June 2013
Recent developments in Geant4 journal August 2015
Some General Relations between the Photoproduction and Scattering of π Mesons journal July 1954
Measurement of K p η Λ near threshold journal October 2001
Amplitude analysis of γ n π p data above 1 GeV journal July 2012
Updated determination of N * resonance parameters using a unitary, multichannel formalism journal May 2019
Recent developments in Geant4
  • Allison, J.; Amako, K.; Apostolakis, J.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 835 https://doi.org/10.1016/j.nima.2016.06.125
journal November 2016
Helicity amplitudes for photoexcitation of nucleon resonances off neutrons journal June 2013
Threshold pion photoproduction on nucleons journal March 1992
Measurement of π 0 photoproduction on the proton at MAMI C journal August 2015
A new measurement of the neutron detection efficiency for the NaI Crystal Ball detector journal April 2015
Structures in K ± -Nucleon Total Cross Sections between 0.9 and 2.4 GeV/ c journal April 1970
Measurement of neutron detection efficiencies in NaI using the Crystal Ball detector
  • Stanislaus, T. D. S.; Koetke, D. D.; Allgower, C.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 462, Issue 3 https://doi.org/10.1016/S0168-9002(01)00180-2
journal April 2001
Angular distributions for single neutral pion photoproduction from neutrons at 450–800 MeV journal May 1972
First measurement of the polarization observable E and helicity-dependent cross sections in single π0 photoproduction from quasi-free nucleons text January 2017
Unified Chew-Mandelstam SAID analysis of pion photoproduction data journal July 2012
T and F asymmetries in π 0 photoproduction on the proton journal May 2016
The 1.5GeV harmonic double-sided microtron at Mainz University
  • Kaiser, K. -H.; Aulenbacher, K.; Chubarov, O.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 593, Issue 3 https://doi.org/10.1016/j.nima.2008.05.018
journal August 2008
Neutral Pion Photoproduction on Neutron journal December 2017
Photoproduction of π 0 mesons off protons and neutrons in the second and third nucleon resonance regions journal June 2018
A focal plane system for the 855 MeV tagged photon spectrometer at MAMI-B
  • Hall, S. J.; Miller, G. J.; Beck, R.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 368, Issue 3 https://doi.org/10.1016/0168-9002(95)00661-3
journal January 1996
Status Report on the Normal Conducting CW Racetrack Microtron Cascade "MAMI" journal August 1983
Analysis of pion photoproduction data journal November 2002
Total photoabsorption cross sections for H 1 , H 2 , and He 3 from 200 to 800 MeV journal January 1996
Threshold π 0 photoproduction on transverse polarised protons at MAMI journal November 2015
Extended partial-wave analysis of π N scattering data journal October 2006
Photon asymmetry measurements of $\overrightarrow{\gamma}p \rightarrow \pi^{0} p$ γ → p → π 0 p for $E_{\gamma}=$ E γ = 320-650 MeV journal November 2016
Incoherent pion photoproduction on the deuteron in the first resonance region journal July 2006
Pion-nucleon partial-wave analysis to 1100 MeV journal September 1985
First measurement of the polarization observable E and helicity-dependent cross sections in single π 0 photoproduction from quasi-free nucleons journal July 2017
High-precision, charge-dependent Bonn nucleon-nucleon potential journal January 2001
π 0 photoproduction on the proton for photon energies from 0.675 to 2.875 GeV journal August 2007
Phenomenological Analysis of Single-Pion Photoproduction journal June 1969
Photoproduction of neutral pions off neutrons in the energy region between 500 MeV and 900 MeV journal May 1973
On the extraction of cross sections for π0 and η photoproduction off neutrons from deuteron data journal March 2016
Recent Developments in Geant4 conference June 2014
Review of Particle Physics text January 2018
Review of Particle Physics text January 2012
Updated analysis of NN elastic scattering to 3 GeV text January 2007
Baryon photo-decay amplitudes at the pole text January 2013
On the Extraction of Cross Sections for pi0 and eta Photoproduction off Neutrons from Deuteron Data text January 2015
Measurement of pi^0 photoproduction on the proton at MAMI C text January 2015
Updated determination of $N^*$ resonance parameters using a unitary, multichannel formalism text January 2018
Analysis of Pion Photoproduction Data text January 2002
Extended Partial-Wave Analysis of piN Scattering Data text January 2006