Speaker
Prof.
Andrzej Kupsc
(Uppsala University)
Description
The well-defined and simple, initial state makes a baryon-antibaryon
pair production at an electron-positron collider a perfect system to
test discrete symmetries in the baryon sector and to study baryon
properties. In particular the production yields are much enhanced
at the vector resonances such as J/psi and psi'. The spin
orientations of the baryon and antibaryon are correlated and, for spin
one-half baryons, the pair is produced either with parallel or
antiparallel helicites. The transitions to the respective helicity states
can acquire a relative phase, due to the strong interaction in the
final state, leading to a time-reversal-odd observable: a transverse
spin polarization of the baryons. The polarization could be
determined for hyperons using their weak decays. This effect was
recently observed
at BESIII in the J/psi->Lambda_bar Lambda process.
The polarization in baryon-antibaryon exclusive processes
allows novel type of experiments such as simultaneous determination of
the Lambda and Lambda_bar decay
asymmetries. In the talk the method will be described and the prospects
for the studies of
weak decays of hyperons and for CP tests in baryon sector will be
discussed.
Primary author
Prof.
Andrzej Kupsc
(Uppsala University)
Peer reviewing
Paper
Paper files:
