Estimate of the Hadronic Production of the Doubly Charmed Baryon ${\Xi }_{cc}$ under GM-VFN Scheme

Abstract

Hadronic production of the doubly charmed baryon ${\Xi }_{cc}$ (${\Xi }_{cc}^{++}$ and ${\Xi }_{cc}^{+}$) is investigated under the general-mass variable-flavor-number (GM-VFN) scheme. The gluon-gluon fusion mechanism and the intrinsic charm mechanisms, i.e. via the sub-processes $g+g\to (cc){[}^3{S}_1{]}_{\bar{3}}+\bar{c}+\bar{c}$, $g+g\to (cc){[}^1{S}_0{]}_6+\bar{c}+\bar{c}$; $g+c\to (cc){[}^3{S}_1{]}_{\bar{3}}+\bar{c}$, $g+c\to (cc){[}^1{S}_0{]}_6+\bar{c}$ and $c+c\to (cc){[}^3{S}_1{]}_{\bar{3}}+g$, $c+c\to (cc){[}^1{S}_0{]}_6+g$, are taken into account in the investigation, where $(cc){[}^3{S}_1{]}_{\bar{3}}$ (in color {\bf $\bar{3}$}) and $(cc){[}^1{S}_0{]}_6$ (in color {\bf 6}) are two possible $S$-wave configurations of the doubly charmed diquark pair $(cc)$ inside the baryon ${\Xi }_{cc}$. Numerical results for the production at hadornic colliders LHC and TEVATRON show that both the contributions from the doubly charmed diquark pairs $(cc){[}^1{S}_0{]}_6$ and $(cc){[}^3{S}_1{]}_{\bar{3}}$ are sizable with the assumption that the two NRQCD matrix elements are equal, and the total contributions from the `intrinsic' charm mechanisms are bigger than those of the gluon-gluon fusion mechanism. For the production in the region of small transverse-momentum $p_t$, the intrinsic mechanisms are dominant over the gluon-gluon fusion mechanism and they can raise the theoretical prediction of the ${\Xi }_{cc}$ by almost one order.

Comments: 26 pages, 8 figures