DAPNIA-06-469 |
---|
Polarization effects in the reaction |
C. Adamuv sv c'in G. I. Gakh E. Tomasi-Gustafsson |
The electron positron annihilation reaction into four pion production has been studied, through the channel $e^++e^-\\rightarrow \\bar \\rho+\\rho $. The differential (and total) cross sections and various polarization observables for this reaction have been calculated in terms of the electromagnetic form factors of the corresponding $\\gamma^*\\rho\\rho $ current. The elements of the spin--density matrix of the $\\rho -$meson were also calculated. Numerical estimations have been done, with the help of phenomenological form factors obtained in the space--like region of the momentum transfer squared and analytically extended to the time-like region. |