ИСТИНА

The lifetime of pi+pi- mesons and difference of pion scattering lengths with isospin 0 and 2 have been measured in experiment DIRAC at CERN with accuracy 4.5% on the base of 21000 atomic pairs collected in 2001-2003. In 2010 the DIRAC collaboration has finished data taking in order to observe K+pi- and pi+K- and to make estimation of lifetime. This opens possibility to check prediction of QCD at low energy for pion-kaon scattering lengths. Also essential amount of pi+pi- atomic pairs (~22000) was taken. Now they used for calibration of the experimental setup, but it future we intend to improve accuracy of pion scattering length measurement. In 2012 data sample for search of long-lived pi+pi- atoms has been collected. Observation of such atoms allows to investigate possibility to measure Lamb shift in pi+pi- atoms. DIRAC experiment has been performed at PS CERN (proton beam energy 24 GeV). Results of simulation shows that essential gain in yield of pi+pi- and piK atoms could be achieved if measurement would be performed at 450 GeV proton beam (SPS CERN).