13.01.2015 16:15

Experimental investigation of (π+π), (πK+), (π+K) atoms and tests of low-energy QCD precision predictions

Leonid Nemenov (CERN/Dubna)

Low-energy QCD allows to calculate the ππ and πK scattering lengths with high precision. There are accurate relations between this scattering lengths and the lifetimes of (π+π), (πK+), and (π+K) atoms.  The two experimental results on lifetime measurement of (π+π) as well as (πK+), (π+K) atoms are presented.  A different way to evaluate ππ scattering lengths is the Lamb shift measurement, which is possible for the long-lived (π+π) atoms.  The results of the experiment on the search for long-lived (π+π)-atoms are described. The (K+K) atoms and other atom yields will be discussed.  All experimental investigations of ππ and πK atoms were done at proton momentum Pp =24GeV/c.  The presented analysis shows that the atom production in the p-nuclear interactions is increasing more than one order of magnitude if the proton momentum Pp will be increased up to 450 GeV/c.  The large yield of dimeson atoms at Pp=450 GeV/c allows to significantly improve on the precision of (π+K), (πK+ ) atom lifetime measurements, to study the long-lived  π+π atoms and to evaluate their Lamb shift value.  In parallel it will be possible to increase the precision of the π+π atom lifetime measurement.  All these measurements allow to test the precise low-energy QCD predictions for πK and ππ scattering lengths with high accuracy. 

 

Category: Kernphysik