Theoretical study of the gamma d -> pi(0)eta d reaction

Author(s)

Torres, A. Martinez ; Khemchandani, K. P. ; Oset, E.

• Document type: Journal article
• Source: PHYSICAL REVIEW C; v. 107, n. 2, p. 24-pg., 2023-02-03.

Abstract

We have done a theoretical study of the gamma d -> pi(0)eta d reaction starting with a realistic model for the gamma N -> pi(0)eta N reaction that reproduces cross sections and polarization observables at low energies and involves the gamma N -> Delta(1700) -> eta Delta(1232) -> eta pi N-0 process. For the coherent reaction in the deuteron we considered the impulse approximation together with the rescattering of the pions and the eta on a different nucleon than the one where they are produced. We found this second mechanism very important since it helps share between two nucleons the otherwise large momentum transfer of the reaction. Other contributions to the gamma d -> pi(0)eta d reaction, involving the gamma N -> pi(+/-)pi N-0' process, followed by the rescattering of the pi(+/-) with another nucleon to give eta and a nucleon, have also been included. We find a natural explanation, tied to the dynamics of our model, for the shift of the eta-d mass distribution to lower invariant masses, and of the pi(0)-d mass distribution to larger invariant masses, compared to a phase space calculation. We also study theoretical uncertainties related to the large momenta of the deuteron wave function involved in the process as well as to the couplings present in the model. Striking differences are found with the experimental angular distribution and further theoretical investigations might be necessary. (AU)

• FAPESP's process: 19/16924-3 - Properties of hadrons and hadron interactions
• Grantee: Kanchan Pradeepkumar Khemchandani
• Support Opportunities: Regular Research Grants
• FAPESP's process: 19/17149-3 - Tackling problems on Hadron Physics using effevtive field theories
• Grantee: Alberto Martinez Torres
• Support Opportunities: Regular Research Grants