Linear momentum transfer in pion accompanied 16O induced reaction on 232Th at 95 MeV per nucleon

doi:10.1016/0375-9474(88)90728-2

Nuclear Physics A

Volume 481, Issue 4, 16 May 1988, Pages 821-833

https://doi.org/10.1016/0375-9474(88)90728-2 Get rights and content

Abstract

Positive pions and protons emitted at 90° were measured in coincidence with two fission fragments in the reaction ¹⁶O + ²³²Th at 95 MeV/nucleon. The linear momentum transfer distribution has been determined from the folding angle between the fragments. The average momentum transfer is 2.5 GeV/c ± 0.2 GeV/c for a pionic reaction. An analysis in terms of impact parameter distributions leads to the conclusion that subthreshold pion production requires a large overlap of projectile and target density profiles.

References (24)

V. Bernard
Nucl. Phys.
(1984)
E. Chiavassa
Nucl. Phys.
(1984)
R. Shyam et al.
Nucl. Phys.
(1984)
J. Aichelin et al.
Phys. Lett.
(1984)
M. Prakash
Phys. Rev.
(1986)
D. Vasak et al.
Nucl. Phys.
(1984)
A. Aiello
preprint INFN
(1987)
S. Leray
J. de Phys.
(1986)
W. Benenson
Phys. Rev. Lett.
(1979)
T. Johansson
Phys. Rev. Lett.
(1982)
H. Noll
Phys. Rev. Lett.
(1984)

H. Heckwolf

Z. Phys.

(1984)

P. Braun-Munzinger

Phys. Rev. Let.

(1984)

Cited by (17)

Investigation of polar and azimuthal distributions of subthreshold pions at intermediate energies
1994, Physics Letters B
We present data on π⁰ emission coincident with projectile-like fragments from ³⁶Ar + ¹⁹⁷Au and ³⁶Ar + ¹²C reactions at 95 MeV/u. The pion polar and azimuthal distributions, obtained for different impact parameters, are interpreted in terms of strong final-state interactions. We propose to exploit pion shadowing as a probe of the competition between attractive and repulsive forces in nucleus-nucleus collisions.
Proton and subthreshold pion production correlated with light fragments: A statistical process?
1993, Nuclear Physics, Section A
Light fragments detected by large-area multidetectors have been measured in coincidence with charged pions and protons for reactions induced by 94 MeV/u ¹⁶O on Al, Ni and Au targets. The production of these particles is shown to obey the statistical decay of the system formed in the primary stage of the reaction, according to the participant/spectator pattern. Triggering pions and protons are emitted by the highly excited reaction zone, the characteristics of which are determined with the help of kinematical correlations. The compatibility between the statistical emission and characteristic reaction times calculated by a dynamical model is examined.
Neutral pion production in the reactions 16O+27Al, 58Ni, 208Pb at E<inf>lab</inf>=95 MeV/nucleon
1992, Nuclear Physics, Section A
The production of neutral pions has been studied in the ¹⁶O+²⁷Al, ⁵⁸Ni, ²⁰⁸Pb reactions at 95 MeV/nucleon. Inclusive pion differential distributions $d σ d p_{t}, d σ d T_{π}$ , and $d σ d Ω$ have been measured by detecting the two-pion decay γ-rays in a setup of 8 lead glass Cherenkov detector telescopes. The data are discussed in the framework of a moving thermal source model. It is shown that the shape of the pion energy spectra is better described if mean field effects on the primary pion-production cross section and pion reabsorption are included in the calculation.
A statistical description of pion production near the absolute threshold
1992, Nuclear Physics, Section A
We discuss a new version of the statistical approach to the finite excited systems, which permits us to include into consideration the finite particle number effects and effects of quantum statistics. Based on such an approach the model of subthreshold pion production is suggested. The results of the calculations show a good agreement with experimental data at the energy range 20–85 MeV/nucleon. Comparison with the evaporation model is presented.
Study of the CLAMSUD magnetic spectrometer focal plane by a simulation code
1991, Nuclear Inst. and Methods in Physics Research, A
A simulation of the performances of the CLAMSUD magnetic spectrometer as a pion detector was carried out by the code GEANT2. A survey of the geometry and the magnetic field of the CLAMSUD spectrometer is first presented. The investigation by means of the code GEANT2 of the spectrometer characteristics (such as solid angle and momentum resolution), pion discrimination by a ΔE-t analysis and muon contamination of pion spectra is reported.
Subthreshold production of pions in coincidence with light particles
1990, Nuclear Physics, Section A
He ions have been detected in coincidence with charged pions in the reactions ¹⁶O on ²⁷Al at E_lab = 94 MeV/u. We analyse velocity spectra and cross-sections of He ions emitted in the angular range 4⁰ ÷ 150⁰ in coincidence with charged pions detected at 90⁰. A two source emission mechanism of the helium particles and a pion statistical production from an equilibrated participant zone is stressed. The absolute yields at different angles are compared with results of a theoretical model for medium energy heavy ion reactions in the frame f a participant-spectator picture. A comparison of the pion energy spectra with Boltzmann-Nordheim-Vlasov calculations and a discussion on the time scale for pion emission is also presented.

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^☆: Experiment performed at GANIL, Caen.

¹: Permanent address: I.N.P. Krakow, Poland.

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Nuclear Physics A

Abstract

References (24)

Nucl. Phys.

Nucl. Phys.

Nucl. Phys.

Phys. Lett.

Phys. Rev.

Nucl. Phys.

preprint INFN

J. de Phys.

Phys. Rev. Lett.

Phys. Rev. Lett.

Phys. Rev. Lett.

Z. Phys.

Phys. Rev. Let.

Cited by (17)

Investigation of polar and azimuthal distributions of subthreshold pions at intermediate energies

Proton and subthreshold pion production correlated with light fragments: A statistical process?

Neutral pion production in the reactions <sup>16</sup>O+<sup>27</sup>Al, <sup>58</sup>Ni, <sup>208</sup>Pb at E<inf>lab</inf>=95 MeV/nucleon

A statistical description of pion production near the absolute threshold

Study of the CLAMSUD magnetic spectrometer focal plane by a simulation code

Subthreshold production of pions in coincidence with light particles

Linear momentum transfer in pion accompanied 16O induced reaction on 232Th at 95 MeV per nucleon☆

Abstract

Nucl. Phys.

Nucl. Phys.

Nucl. Phys.

Phys. Lett.

Phys. Rev.

Nucl. Phys.

J. de Phys.

Phys. Rev. Lett.

Phys. Rev. Lett.

Phys. Rev. Lett.

Z. Phys.

Phys. Rev. Let.

Linear momentum transfer in pion accompanied ¹⁶O induced reaction on ²³²Th at 95 MeV per nucleon☆