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 $O(\alpha^3_s\alpha)$-order, the estimates for the $\gamma p$ cross-section of the $D^*$-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 $<O_{(8)} > \approx 0.33-0.49 GeV^3$.