DIRAC CollaborationAdeva Andany, BernardoLópez Aguera, María de los ÁngelesPló Casasús, MáximoRomero Vidal, AntonioSaborido Silva, Juan JoséZrelov, P.2025-01-292025-01-292009-04-06Physics Letters B Volume 674, Issue 1, 6 April 2009, Pages 11-160370-2693https://hdl.handle.net/10347/39263We present evidence for the first observation of electromagnetically bound π±K∓-pairs (πK-atoms) with the DIRAC experiment at the CERN-PS. The πK-atoms are produced by the 24 GeV/c proton beam in a thin Pt-target and the π± and K∓-mesons from the atom dissociation are analyzed in a twoarm magnetic spectrometer. The observed enhancement at low relative momentum corresponds to the production of 173 ± 54 πK-atoms. The mean life of πK-atoms is related to the s-wave πK-scattering lengths, the measurement of which is the goal of the experiment. From these first data we derive a lower limit for the mean life of 0.8 fs at 90% confidence level.engAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/DIRAC experimentExotic atomsScattering lengπK-scatteringthChiral perturbation220703 Física atómicajournal article10.1016/j.physletb.2009.03.001open access