Hadronic production of ${\mathrm{\Xi }}_{cc}$ at a fixed-target experiment at the LHC

In the paper, we present a detailed discussion on the ${\mathrm{\Xi }}_{cc}$ production at a fixed target experiment at the LHC (After@LHC). The doubly charmed baryon ${\mathrm{\Xi }}_{cc}$ is produced via the channel, ${\rm Proton} + {\rm Proton}\to\Xi_{cc}+X$. In estimating its hadroproduction, we discuss three dominant subprocesses, e.g. $g+g\to {\mathrm{\Xi }}_{cc}+\bar{c}+\bar{c}$, $g+c\to \Xi_{cc}+\bar{c}$and$c+c\to \Xi_{cc}+g$. During the production, it shall first generate a binding diquark and then form the ${\mathrm{\Xi }}_{cc}$ baryon by grabbing soft light-quarks or gluons. We observe that both the two diquark configurations $(cc){[}^3{S}_1{]}_{\bar{\mathbf{3}}}$ and $(cc){[}^1{S}_0{]}_{\mathbf{6}}$ can have sizable contributions to the ${\mathrm{\Xi }}_{cc}$ production. Large number of ${\mathrm{\Xi }}_{cc}$ events can be generated at the After@LHC, whose total production cross section is larger than that of the SELEX experiment by about thirty-five times. It may also possible to study the properties of ${\mathrm{\Xi }}_{bc}$ at the After@LHC. More specifically, we shall have about $8.3\times {10}^6$ ${\mathrm{\Xi }}_{cc}$ events/year and $1.8\times {10}^4$ ${\mathrm{\Xi }}_{bc}$ events/year when its integrated luminosity approaches to $2$ fb${}^{-1}$/year. Thus, in addition to SELEX and LHC, the After@LHC shall provide another useful platform for studying the baryon properties.