Exclusive photoproduction of charmed D * vector mesons, , or

E. Tomasi-Gustafsson; M. P. Rekalo

doi:10.1140/epja/i2004-10005-1

EPJ

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2024 Impact factor 2.8

Hadrons and Nuclei

Eur. Phys. J. A (2004) 21: 469-478
https://doi.org/10.1140/epja/i2004-10005-1

Exclusive photoproduction of charmed D ^* vector mesons, $\gamma + N\rightarrow Y_c + \overline{D^*}$ , $Y_c = \Lambda_c^ +$ or $\Sigma_c$

E. Tomasi-Gustafsson¹^* and M. P. Rekalo²

¹ DAPNIA/SPhN, CEA/Saclay, 91191, Gif-sur-Yvette Cedex, France
² NSC Kharkov Institute of Physics and Technology, 61108, Kharkov, Ukraine

^* e-mail: etomasi@cea.fr

Abstract

The spin structure of the matrix element for the reactions $\gamma + N\rightarrow Y_c + {D}^*$ , where $Y_c = \Lambda_c^ + (2285)$ , $\Sigma_c(2455)$ are charmed baryons with spin 1/2, and D ^*(2010) is the vector charmed meson, can be parametrized, in collinear regime, in terms of three independent scalar amplitudes, which are functions of the photon energy $E_{\gamma}$ , only. In the framework of an effective Lagrangian approach generalized to charm photoproduction, we calculate the energy dependence of the differential cross-section, the density matrix element of $\overline{D}^*$ , $\rho_{11}$ , the asymmetry A _z in the collision of circularly polarized photons with polarized nucleons, and the polarization of the produced Y _c-hyperon, P _z, in the collision of circularly polarized photons with unpolarized target. All these polarization observables either vanish or are large, in absolute value, with a smooth $E_{\gamma}$ -dependence, and differ for $\Lambda_c^ +$ and $\Sigma_c$ production.