Pion production in nucleon-nucleon collisions in chiral effective field theory with Delta(1232)-degrees of freedom

Abstract

A calculation of the pion-production operator up to next-to-next-to-leading order for s-wave pions is performed within chiral effective field theory. In the previous study [Phys. Rev. C 85, 054001 (2012)] we discussed the contribution of the pion-nucleon loops at the same order. Here we extend that study to include explicit Delta degrees of freedom and the 1/m_N^2 corrections to the pion-production amplitude. Using the power counting scheme where the Delta-nucleon mass difference is of the order of the characteristic momentum scale in the production process, we calculate all tree-level and loop diagrams involving Delta up to next-to-next-to-leading order. The long-range part of the Delta loop contributions is found to be of similar size to that from the pion-nucleon loops which supports the counting scheme. The net effect of pion-nucleon and Delta loops is expected to play a crucial role in understanding of the neutral pion production data.

29 pages, 12 figures

References in corpus (7)

• Chiral Perturbation Theory and Baryon Properties
• Bound state nature of the exotic Z_b states
• Remarks on N N -> N N pi beyond leading order
• Pion production in nucleon-nucleon collisions in chiral effective field theory: next-to-next-to-leading order contributions
• Bridging over p-wave pi-production and weak processes in few-nucleon systems with chiral perturbation theory
• Two-pion-exchange and other higher-order contributions to the $pp\to pp{\pi }^0$ reaction
• Impulse approximation in nuclear pion production reactions: absence of a one-body operator

Cited by in corpus (8)

• Effective Field Theory calculations of $NN\to NN\pi$
• Charge Symmetry Breaking in dd->4Heπ0 with WASA-at-COSY
• Nucleon-nucleon resonances at intermediate energies using a complex energy formalism
• Two-pion exchange for coupled-channel scattering of two heavy mesons
• Threshold pion production in proton-proton collisions at NNLO in chiral EFT
• $P$-wave dibaryon resonances in $pp$ elastic scattering and near-threshold pion production
• Importance of d-wave contributions in the charge symmetry breaking reaction $dd\to {}^4\text{He}{\pi }^0$
• Pion absorption from the lowest atomic orbital in 2H, 3H and 3He