Polarization phenomena in open charm photoproduction processes

Abstract

We analyze polarization effects in associative photoproduction of pseudoscalar ($\bar{D}$) charmed mesons in exclusive processes $\gamma +N\to Y_c+\bar{D}$, $Y_c={\Lambda }_c^{+}$, ${\Sigma }_c$. Circularly polarized photons induce nonzero polarization of the $Y_c$-hyperon with $x$- and $z$-components (in the reaction plane) and non vanishing asymmetries ${\mathcal{A}}_x$ and ${\mathcal{A}}_z$ for polarized nucleon target. These polarization observables can be predicted in model-independent way for exclusive $\bar{D}$-production processes in collinear kinematics. The T-even $Y_c$-polarization and asymmetries for non-collinear kinematics can be calculated in framework of an effective Lagrangian approach. The depolarization coefficients $D_{ab}$, characterizing the dependence of the $Y_c$-polarization on the nucleon polarization are also calculated.

Comments: 36 pages 13 figures