====== TTP07-03 Spin asymmetries and correlations in Lambda-pair production through the radiative return method ======
 
 
   <hidden TTP07-03  Spin asymmetries and correlations in Lambda-pair production through the radiative return method >  Exclusive baryon pair production through the radiative return
  is a unique tool to determine the electric and the magnetic form factors
  in the timelike region over a wide range of energies. The decay of 
  $\Lambda$-baryons into $p +\pi^-$ can be used to measure
  their spin and to analyze
  spin-spin correlations in the  $\bar\Lambda\Lambda$ system.
  We evaluate the spin dependent hadronic tensor, which describes this reaction,
  calculate the corresponding cross section for 
  $e^+e^- \to \Lambda\bar\Lambda$ and $e^+e^- \to \Lambda\bar\Lambda\gamma$
  with subsequent decays of  $\Lambda$ and $\bar\Lambda$ and present a compact
  formula for the correlated distribution. We demonstrate that the relative
  phase between the electric and the magnetic form factor can be determined
  in this analysis by considering single spin asymmetries and correlated
  decay distributions. The reaction is implemented in the event generator
   PHOKHARA. It is demonstrated that the relative phase can be measured 
 with the event sample presently accumulated at $B$- factories.
 </hidden>
|**H. Czyz, A. Grzelinska and J.H. Kuhn**  | 
|**  Phys.Rev.  D75 074026 2007  **  |
| {{preprints:2007:ttp07-03.pdf|PDF}} {{preprints:2007:ttp07-03.ps|PostScript}} [[http://arxiv.org/abs/hep-ph/0702122|arXiv]]   |
| |