Ground-state energy of pionic hydrogen to one loop
High Energy Physics - Phenomenology
2009-01-07 v2
Abstract
We investigate the ground-state energy of the pi- p atom (pionic hydrogen) in the framework of QCD+QED. In particular, we evaluate the strong energy-level shift. We perform the calculation at next-to-leading order in the low-energy expansion in the framework of the relevant effective field theory. The result provides a relation between the strong energy shift and the pion-nucleon S-wave scattering lengths - evaluated in pure QCD - at next-to-leading order in isospin breaking and in the low-energy expansion. We compare our result with available model calculations.
Cite
@article{arxiv.hep-ph/0206068,
title = {Ground-state energy of pionic hydrogen to one loop},
author = {J. Gasser and M. A. Ivanov and E. Lipartia and M. Mojzis and A. Rusetsky},
journal= {arXiv preprint arXiv:hep-ph/0206068},
year = {2009}
}
Comments
Version accepted for publication in Eur. Phys. J. C; Eq. (B8) corrected, comment after Eq. (B11) changed, additional minor changes in the text; preprint number added