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1–6 Sept 2019
University of Surrey
Europe/London timezone

Three-Nucleon Force Effects in the FSI configuration of the d(n,nn)p Breakup

5 Sept 2019, 19:10
20m
University of Surrey

University of Surrey

Poster Posters Poster Session

Speaker

Prof. Hiroyuki Kamada (Kyushu Institute of Technology)

Description

We investigated three-nucleon force (3NF) effects in the Final State Interaction (FSI) configuration of the d(n,nn)p breakup reaction. Solutions of the 3N Faddeev equations [1] with the CDBonn nucleon-nucleon potential [2] and the Tucson-Melbourne 3NF [3] give access not only to the elastic scattering observables but also to the three-body breakup ones. In this contribution we focus on an integrated breakup cross section around the final state interaction condition for two neutrons:
d2σdΩ1dΩ2S0ΔSS0+ΔSd3σdΩ1dΩ2dSdS|Ω1=Ω2     (n+dp+(nn))                                     (1)
Here Ω1 and Ω2 represent the directions of the momenta of outgoing neutrons 1 and 2, respectively. For fixed Ω1 and Ω2, the arc-length variable S defines uniquely the three-nucleon kinematics, yielding a specific (E1,E2) point on the allowed kinematical curve in the (E1,E2) plane, where E1 and E2 are the kinetic energies of neutron 1 and 2, respectively. Choosing an appropriate starting point where S=0, S is calculated as a distance taken along the curve from its starting point:
S=dS=(dE1)2+(dE2)2                                                                                   (2)
where E1 and E2 are the kinetic energies of neutron 1 and 2, respectively. The FSI occurs at the condition E1=E2 at the parameter S=S0.

Fig.1 shows the integrated breakup cross section of Eq.(1) at the incident neutron laboratory energy Elab=200 MeV with the averaging width parameter ΔS= 20 MeV. The angle θlab is the laboratory scattering angle of nucleons 1 and 2, for which the FSI condition is realized.
Integrated final state interaction configuration breakup cross section for the incident neutron laboratory kinetic energy 200 MeV. The theoretical predictions based solely on a two-nucleon interaction (here the the CDBonn potential $[2]$) are represented by the dotted line, while the results obtained with the two-nucleon potential augmented by the the Tucson-Melbourne 3NF $[3]$ are shown with the solid line.
We found a large deviation between the theoretical predictions including or not including 3NF. Although the 3NF effects for the elastic scattering cross section are located predominantly in the region starting from middle up to backward scattering angles,the 3NF effects for the integrated FSI configuration breakup cross section are found also at forward scattering angles.

  1. W. Gloeckle, H. Witala, D. Hueber, H. Kamada, J. Golak, Phys. Rep. 274, 107 (1996).
  2. R. Machleidt, Phys. Rev. C 63, 024001 (2001).
  3. S. A. Coon, H. K. Han, Few Body Syst. 30,131 (2001).

Author

Prof. Hiroyuki Kamada (Kyushu Institute of Technology)

Co-authors

Prof. Henryk Witała (M. Smoluchowski Institute of Physics, Jagiellonian University) Prof. Jacek Golak (M. Smoluchowski Institute of Physics, Jagiellonian University) Prof. Roman Skibiński (M. Smoluchowski Institute of Physics, Jagiellonian University)

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