Some Features of the Hadronic $B_c^{(*)}$-meson Production at Large $p_T$

TL;DR

The paper investigates hadronic production of $B_c^{(*)}$ mesons at large $p_T$, challenging the validity of the fragmentation model in this regime. By performing the complete set of $O(\alpha_s^4)$ diagrams for $gg\rightarrow B_c^{(*)}+X$ and analyzing the role of recombination diagrams, it shows fragmentation fails to describe cross-sections across the accessible $p_T$ range and yields a different vector-to-pseudoscalar ratio. Convolution with proton structure functions at $\sqrt{s}=1.8$ TeV and realistic rapidity cuts provides concrete differential cross-sections and Run Ib event-rate estimates, underscoring the importance of full perturbative QCD calculations for heavy-quark hadronization. These results have direct implications for interpreting heavy-quark bound-state production at hadron colliders and for planning experimental searches for $B_c^{(*)}$ mesons.

Abstract

Calculations of the hadronic $B^{(*)}_c$-mesons production performed in the framework of the perturbative QCD taking into account $O(α_s^4)$ Feynmann diagrams are presented. A comparison of the exact calculations with those based on the fragmentation model of $\bar b\rightarrow B^{(*)}_c+X$ shows the large discrepancy between them. The exact calculations of the $B^{(*)}_c$-mesons production cross-sections as the function of $p_T$ at the energy of the FNAL Tevatron ($\sqrt{s}=1.8$ TeV) are given. The predicted ratio of the vector to the pseudoscalar state cross-sections is about $R\sim 3$ instead of $R\sim 1.4$ for the fragmentation model.