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arXiv · hep-ex/0409053

Detection of $π^+π^-$atoms with the DIRAC spectrometer at CERN

The DIRAC collaboration
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Abstract

The goal of the DIRAC experiment at CERN is to measure with high precision the lifetime of the $π^+π^-$ atom ($A_{2π}$), which is of order $3\times10^{-15}$ s, and thus to determine the s-wave $ππ$-scattering lengths difference $|a_{0}-a_{2}|$. $A_{2π}$ atoms are detected through the characteristic features of $π^+π^-$ 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.

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The DIRAC collaboration. 2004-09-28. Detection of $π^+π^-$atoms with the DIRAC spectrometer at CERN. https://doi.org/10.1088/0954-3899%2F30%2F12%2F012

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