Observation of ${\pi }^{-}{K}^{+}$ and ${\pi }^{+}{K}^{-}$ atoms

DIRAC Collaboration

The observation of hydrogen-like $\pi K$ atoms, consisting of ${\pi }^{-}{K}^{+}$ or ${\pi }^{+}{K}^{-}$ mesons, is presented. The atoms have been produced by 24 GeV/$c$ protons from the CERN PS accelera…