Detection of ${\pi }^{+}{\pi }^{-}$atoms with the DIRAC spectrometer at CERN

Abstract

The goal of the DIRAC experiment at CERN is to measure with high precision the lifetime of the ${\pi }^{+}{\pi }^{-}$ atom ($A_{2\pi }$), which is of order $3\times 10^{-15}$ s, and thus to determine the s-wave $\pi \pi$-scattering lengths difference $|a_0-a_2|$. $A_{2\pi }$ atoms are detected through the characteristic features of ${\pi }^{+}{\pi }^{-}$ pairs from the atom break-up (ionization) in the target. We report on a first high statistics atomic data sample obtained from p Ni interactions at 24 GeV/$c$ proton momentum and present the methods to separate the signal from the background.

19 pages, 12 figures, 1 table

Cited by in corpus (12)

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• Chiral corrections to ${\pi }^{-}\gamma \to 3\pi$ processes at low energies
• Hadronic Atoms
• Measurement of the $\pi K$ atom lifetime and the $\pi K$ scattering length
• Energy and decay width of the pi-K atom
• A Complete Version of the Glauber Theory for Elementary Atom - Target Atom Scattering and Its Approximations
• Formation of $\pi \mu$ atoms in $K_{μ4} decay
• Investigation of $K^{+}{K}^{-}$ pairs in the effective mass region near $2m_K$