Ground-state energy of pionic hydrogen to one loop

J Gasser, MA Ivanov, Edisher Lipartia, M Mojzis, A Rusetsky

Research output: Contribution to journalArticlepeer-review

120 Citations (SciVal)


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.
Original languageEnglish
Pages (from-to)13-34
JournalEuropean Physical Journal C. Particles and Fields
Issue number1
Publication statusPublished - 2002

Subject classification (UKÄ)

  • Subatomic Physics


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