0000000000615802
AUTHOR
C. Garcia Recio
Chiral unitary theory: Application to nuclear problems
In this talk we briefly describe some basic elements of chiral perturbation theory, $\chi PT$, and how the implementation of unitarity and other novel elements lead to a better expansion of the $T$ matrix for meson meson and meson baryon interactions. Applications are then done to the $ \pi \pi $ interaction in nuclear matter in the scalar and vector channels, antikaons in nuclei and $K^-$ atoms, and how the $\phi$ meson properties are changed in a nuclear medium.
Eta bound states in nuclei
The energies and widths of bound states of the $\eta$ meson in different nuclei are obtained using the results for its selfenergy in a nuclear medium, which is evaluated in a selfconsistent manner using techniques of unitarized chiral perturbation theory. We find bound states in all studied nuclei (from $^{12}{C}$ on) and the half widths obtained are larger than the separation of the levels, what makes the experimental observation of peaks unlikely. We have paid a special attention to the region of nuclei where only the $1s$ state appears and the binding energies are of the order of magnitude of the half width, which would magnify the chances that some broad peak could be observed. This is …