Related papers: Pionic correlations and meson-exchange currents in…
Meson-exchange currents (MEC) play a crucial role in the nuclear response to a leptonic probe, inducing the emission of two nucleons, the so-called 2p2h excitations. Here we report the results of our recent work \cite{Belocchi:2025eix}, in…
A brief discussion of the elastic pion-pion scattering amplitude to two loops in chiral perturbation theory is given. Some technical details of the evaluation of two-loop diagrams are addressed, and results relevant for the pionium decay…
A new tool which combines chiral perturbation theory and unitarity in coupled channels is applied with success to the study of the meson-meson interaction, extending the theoretical predictions up to sqrt{s} = 1.2 GeV, hence improving…
Pion exchange is the central ingredient to nucleon-nucleon interactions used in nuclear structure calculations, and one pion exchange (OPE) enters at leading order in chiral effective field theory. In the $^{2S+1}L_J={^1S_0}$ partial wave,…
Following recent studies of inclusive electron scattering from nuclei at high energies which focused on two-nucleon emission mediated by meson-exchange currents, in this work the superscaling behavior of such contributions is investigated.…
We discuss the two-pion exchange potential which emerges from a box diagram with one nucleon (the spectator) restricted to its mass shell, and the other nucleon line replaced by a subtracted, covariant $\pi N$ scattering amplitude which…
Leading-order electromagnetic loop corrections to the one-pion-exchange potential are computed within the framework of chiral perturbation theory. These corrections generate an effective nucleon-nucleon potential, $V_{\pi \gamma}$, which…
We present calculations of the two-pion-exchange contribution to proton-proton scattering at 90 degrees using form factors appropriate for representing the distribution of the constituent partons of the nucleon. Talk given at MENU2001,…
Our previous study of the near-threshold pp\to pp\pi^0 reaction based on a hybrid nuclear effective field theory is further elaborated by examining the momentum dependence of the relevant transition operators. We show that the two-pion…
The elastic backward proton-deuteron scattering is analyzed within a covariant approach based on the Bethe-Salpeter equation with realistic meson-exchange interaction. Contributions of the one-nucleon and one-pion exchange mechanisms to the…
We use a recently developed model of relativistic meson-exchange currents to compute the neutron-proton and proton-proton yields in $(\nu_\mu,\mu^-)$ scattering from $^{12}$C in the 2p-2h channel. We compute the response functions and cross…
A general derivation of the multi-pion correlation function for completely chaotic source is given. Its effects on the pion multiplicity distribution, two-pion interferometry are studied. A generalized multi-pion correlation function for a…
Parity-violating quasielastic electron scattering is studied within the context of the relativistic Fermi gas and its extensions to include the effects of pionic correlations and meson-exchange currents. The work builds on previous studies…
Elastic pion-pion and pion-nucleon scattering are reviewed in the context of chiral perturbation theory. Theoretical results from systematic low-energy expansions to O(p^6) for pion-pion and to O(p^3) for pion-nucleon scattering are…
Elastic scattering of pions from finite nuclei is investigated utilizing a contemporary, momentum--space first--order optical potential combined with microscopic estimates of second--order corrections. The calculation of the first--order…
Two-particle two-hole contributions to electroweak response functions are computed in a fully relativistic Fermi gas, assuming that the electroweak current matrix elements are independent of the kinematics. We analyze the genuine…
In close analogy to fermionic many-body theory the truncation of the bosonic BBGKY density matrix hierarchy on the two-body level leads to a coupled set of nonlinear equations of motion for the one-body density matrix and the two-body…
The process of two pion production in the electron-polarized proton scattering is investigated. In the Weizs\"acker-Williams approximation the differential spectral distributions and the spin-momentum correlations are considered. The spin…
The binding energy of nuclear matter including exchange and pionic effects is calculated in a quark-meson coupling model with massive constituent quarks. As in the case with elementary nucleons in QHD, exchange effects are repulsive.…
By a reformulation of the loop expansion in the Resonance-Spectrum-Expansion amplitude for meson-meson scattering, in terms of s-channel exchange of families of propagator modes, we obtain a formalism which allows for a wider range of…