pi(-)p atom in ChPT: strong energy-level shift
arXiv:hep-ph/0009206 · doi:10.1016/S0370-2693(00)01185-0
Abstract
The general formula of the pi(-)p atom strong energy-level shift in the 1s state is derived in the next-to-leading order in the isospin breaking, and in all orders in chiral expansion. Isospin-breaking corrections to the level shift are explicitly evaluated at order p^2 in ChPT. The results clearly demonstrate the necessity to critically reaccess the values of the piN scattering lengths, extracted from the energy-level shift measurement by means of the potential model-based theoretical analysis.
16 pages, LaTeX-file, 1 Figure