Total and differential cross sections for pion production via coherent isobar and giant resonance formation in heavy-ion collisions

1985 ◽  
Vol 63 (9) ◽  
pp. 1242-1248 ◽  
Author(s):  
P. A. Deutchman ◽  
J. W. Norbury ◽  
L. W. Townsend

A quantal many-body formalism is presented that investigates pion production through the coherent formation of a nucleonic isobar in the projectile and its subsequent decay to various pion charge states along with concomitant excitation of the target to a coherent spin–isospin giant resonance via a peripheral collision of relativistic heavy ions. Total cross sections as a function of the incident energy per nucleon and Lorentz-invariant differential cross sections as a function of pion energy and angle are calculated. It is shown that the pion angular distributions, in coincidence with the target giant resonance excitations, might provide a well-defined signature for these coherent processes.

1993 ◽  
Vol 08 (26) ◽  
pp. 4667-4678
Author(s):  
K.M. ABUMURAD

The Lorentz-invariant differential cross section (LIDCS) for π production in heavy ion collisions was studied through the two-step process, NN→NΔ→NNπ. A phenomenological interaction potential containing central and tensor terms was used. The effect of inclusion of the tensor term on the LIDCS was little. The target nucleus 12C was excited to one of its giant resonance states, Jπ=1+, T=1, while the projectile nucleus 16O was excited to an isobar Δ (M=1232 MeV , ΓΔ=115.11 MeV ) which decayed (NΔ→NNπ), giving a nucleon and a pion mπ=138 MeV . In comparison with available experimental data, the shape was reproduced, but the theoretical results were higher.


2009 ◽  
Vol 24 (02n03) ◽  
pp. 450-453
Author(s):  
◽  
T. SKORODKO ◽  
M. BASHKANOV ◽  
D. BOGOSLOWSKY ◽  
H. CALÉN ◽  
...  

The two-pion production in pp-collisions has been investigated in exclusive measurements from threshold up to Tp = 1.36 GeV . Total and differential cross sections have been obtained for the channels pnπ+π0, ppπ+π-, ppπ0π0 and also nnπ+π+. For intermediate incident energies Tp > 1 GeV , i.e. in the region, which is beyond the Roper excitation but at the onset of ΔΔ excitation the total ppπ0π0 cross section falls behind theoretical predictions by as much as an order of magnitude near 1.2 GeV, whereas the nnπ+π+ cross section is a factor of five larger than predicted. A model-unconstrained isospin decompostion of the cross section points to a significant contribution of an isospin 3/2 resonance other than the Δ(1232). As a possible candidate the Δ(1600) is discussed.


2014 ◽  
Vol 50 (11) ◽  
Author(s):  
V. V. Sargsyan ◽  
G. G. Adamian ◽  
N. V. Antonenko ◽  
A. Diaz-Torres ◽  
P. R. S. Gomes ◽  
...  

2005 ◽  
Vol 20 (02n03) ◽  
pp. 263-272
Author(s):  
PAOLO CAMERINI

The results of an extensive campaign of measurements of the π→ππ process in the nucleon and nuclei at intermediate energies are presented. Several differential cross-sections were measured following the detection of multiparticle (π+,π+π±) and (π+,π+π-p) events, which allowed to understand the general properties of the pion production reaction inside the nucleus. Particular attention was devoted to the study of the effects of nuclear matter on the π-π scalar-isoscalar system. The most relevant results are reviewed and compared to theories as well as to other recent experimental results.


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