Friday, November 16 , 2001, 16:00
Dr. J. Schacher, Bern
Abstract:
The goal of DIRAC is to measure the \pi^+\pi^- atom (pionium)
lifetime with 10% precision. The magnetic double arm
spectrometer is detecting and analysing pionia, produced
in the high intensity 24 GeV/c proton beam of the CERN
Proton Synchrotron. Since the value of the pionium lifetime
of order 10^{-15} s is dictated by low energy strong
interaction, a precise measurement of this quantity enables
to study characteristic pion parameters in detail and
to submit QCD predictions, calculated in the framework of
chiral perturbation theory, to a severe check.
First evidence for pionium production and a very preliminary lifetime
evaluation will be presented.