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After having announced the statistically significant observation (5.6~$sigma$) of the new exotic $pi K$ atom, the DIRAC experiment at the CERN proton synchrotron presents the measurement of the corresponding atom lifetime, based on the full $pi K$ data sample: $tau = (5.5^{+5.0}_{-2.8}) cdot 10^{-15}s$. By means of a precise relation ($<1%$) between atom lifetime and scattering length, the following value for the S-wave isospin-odd $pi K$ scattering length $a_0^{-}~=~frac{1}{3}(a_{1/2}-a_{3/2})$ has been derived: $left|a_0^-right| = (0.072^{+0.031}_{-0.020}) M_{pi}^{-1}$.
The results of a search for hydrogen-like atoms consisting of $pi^{mp}K^{pm}$ mesons are presented. Evidence for $pi K$ atom production by 24 GeV/c protons from CERN PS interacting with a nickel target has been seen in terms of characteristic $pi K$
The adapted DIRAC experiment at the CERN PS accelerator observed for the first time long-lived hydrogen-like $pi^+pi^-$ atoms, produced by protons hitting a beryllium target. A part of these atoms crossed the gap of 96~mm and got broken up in the 2.1
The branching fractions of the doubly Cabibbo-suppressed decays $D^+rightarrow K^-K^+K^+$, $D^+rightarrow pi^-pi^+K^+$ and $D^+_srightarrowpi^-K^+K^+$ are measured using the decays $D^+rightarrow K^-pi^+pi^+$ and $D^+_srightarrow K^-K^+pi^+$ as norma
The process $e^+e^- to K^+K^-pi^+pi^-$ has been studied in the center-of-mass energy range from 1500 to 2000,MeV using a data sample of 23 pb$^{-1}$ collected with the CMD-3 detector at the VEPP-2000 $e^+e^-$ collider. Using about 24000 selected even
A measurement of the rate for the wrong-sign decay D0 -> K+ pi- pi+ pi- relative to that for the right-sign decay D0 -> K- pi+ pi+ pi- is presented. Using 791 fb-1 of data collected with the Belle detector, we obtain a branching fraction ratio of R_W