New Insight into the Photoproduction of D-star meson in QCD

Abstract

In the framework of the model motivated by perturbative calculations in the fourth $O({\alpha }_s^3\alpha )$-order, the estimates for the $\gamma p$ cross-section of the $D^{\ast }$-meson production in the ZEUS experiment are performed. We factorize the hadronization of $(c\bar{q})$-state hardly produced in perturbative QCD, which allows us to take into account the higher twist terms in the powers of $1/p_T$ at $p_T\sim m_c$ and to correctly reproduce the c-quark fragmentation dominant at high $p_T\gg m_c$ to the given order of ${\alpha }_s$. We find a good agreement with the experimental data on the photoproduction, if the color-octet $(c\bar{q})$-state is taken into account, which yields $<O_{(8)}>\approx 0.33-0.49Ge{V}^3$.

Comments: 10 pages, LATEX file, 5 ps-figures, short corrections added