Published March 2013 | Version v1
Journal article Metadata-only

Coherent photoproduction of π0- and η-mesons off 7Li

Creators

  • 1. University of Basel, Department of Physics, Basel (Switzerland)
  • 2. University of Mainz, Institut fuer Kernphysik, Mainz (Germany)
  • 3. University of Glasgow, School of Physics and Astronomy, Glasgow (United Kingdom)
  • 4. University of Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany)
  • 5. Petersburg Nuclear Physics Institute, Gatchina (Russian Federation)
  • 6. INFN, Sezione di Pavia, Pavia (Italy)
  • 7. University of Edinburgh, School of Physics, Edinburgh (United Kingdom)
  • 8. The George Washington University, Center for Nuclear Studies, Washington, DC (United States)
  • 9. University of California Los Angeles, Los Angeles, California (United States)
  • 10. Lebedev Physical Institute, Moscow (Russian Federation)
  • 11. University of Giessen, II. Physikalisches Institut, Giessen (Germany)
  • 12. Tomsk Polytechnic University, Laboratory of Mathematical Physics, Tomsk (Russian Federation)
  • 13. Mount Allison University, Sackville (Canada)
  • 14. Rudjer Boskovic Institute, Zagreb (Croatia)
  • 15. Institute for Nuclear Research, Moscow (Russian Federation)
  • 16. Kent State University, Kent, Ohio (United States)
  • 17. The Catholic University of America, Washington, DC (United States)

Description

Coherent photoproduction of π0-mesons from threshold (Eth ∼ 136 MeV) throughout the Δ-resonance region and of η-mesons close to the production threshold (Eth ∼ 570 MeV) for η has been measured for 7Li nuclei. The experiment was performed using the tagged-photon beam of the Mainz MAMI accelerator with the Crystal Ball and TAPS detectors combined to give an almost 4 π solid-angle electromagnetic calorimeter. The reactions were identified by a combined invariant-mass and missing-energy analysis. A comparison of the pion data to plane-wave impulse modelling tests the nuclear mass form factor. So far coherent η production had been only identified for the lightest nuclear systems (2H and 3He). For 3He a large enhancement of the cross section above plane-wave approximations had been reported, indicating the formation of a quasi-bound state. The present Li data for η production agree with a plane-wave approximation. Contrary to 3He, neither a threshold enhancement of the total cross section nor a deviation of the angular distributions from the expected form factor dependence were observed. (orig.)

Availability note (English)

Available from: http://dx.doi.org/10.1140/epja/i2013-13038-3

Additional details

Identifiers

DOI
10.1140/epja/i2013-13038-3;

Publishing Information

Journal Title
European Physical Journal. A
Journal Volume
49
Journal Issue
3
Journal Page Range
p. 1-14
ISSN
1434-6001

INIS

Country of Publication
Germany
Country of Input or Organization
Germany
INIS RN
44069448
Subject category
S73: NUCLEAR PHYSICS AND RADIATION PHYSICS;
Resource subtype / Literary indicator
Numerical Data
Descriptors DEI
ANGULAR DISTRIBUTION; COHERENT PRODUCTION; ETA MESONS; EXCITATION FUNCTIONS; EXPERIMENTAL DATA; INTEGRAL CROSS SECTIONS; LITHIUM 7; LITHIUM 7 TARGET; MEV RANGE 100-1000; PHOTONUCLEAR REACTIONS; PHOTOPRODUCTION; PIONS NEUTRAL
Descriptors DEC
BASIC INTERACTIONS; BOSONS; CROSS SECTIONS; DATA; DIFFERENTIAL CROSS SECTIONS; DISTRIBUTION; ELECTROMAGNETIC INTERACTIONS; ELEMENTARY PARTICLES; ENERGY RANGE; FUNCTIONS; HADRONS; INFORMATION; INTERACTIONS; ISOTOPES; LIGHT NUCLEI; LITHIUM ISOTOPES; MESONS; MEV RANGE; NUCLEAR REACTIONS; NUCLEI; NUMERICAL DATA; ODD-EVEN NUCLEI; PARTICLE INTERACTIONS; PARTICLE PRODUCTION; PIONS; PSEUDOSCALAR MESONS; STABLE ISOTOPES; TARGETS

Optional Information

Collaborations
The Crystal Ball at MAMI, TAPS, and A-Two Collaborations