Impacts of the intrinsic charm content of the proton on the ${\mathrm{\Xi }}_{cc}$ hadroproduction at a fixed target experiment at the LHC

In the present paper, we present detailed discussions on the hadronic production of ${\mathrm{\Xi }}_{cc}$ at a fixed target experiment at the LHC (After@LHC). The charm quarks in the hadron could be either extrinsic or intrinsic. By using the Brodsky-Hoye-Peterson-Sakai (BHPS) model as the intrinsic charm distribution function in the proton, we observe that even if by setting the proportion of finding the intrinsic charm in a proton as $A_{\mathrm{in}}=1\%$, the total cross sections for the $g+c$ and $c+c$ production mechanisms shall be enhanced by nearly two times. Thus, the number of ${\mathrm{\Xi }}_{cc}$ events to be generated at the After@LHC can be greatly enhanced. Since the total cross sections and differential distributions for the ${\mathrm{\Xi }}_{cc}$ production at the After@LHC are sensitive to the value of $A_{\mathrm{in}}$, the After@LHC could be a good platform for testing the idea of intrinsic charm.

Figure 1

Typical Feynman diagrams for the intrinsic mechanism through nonperturbative fluctuations of the proton state to the five-quark Fock state. The dashed lines stand for soft interactions.

Figure 2

Comparison of the $p_t$ distributions for the hadroproduction of ${\mathrm{\Xi }}_{cc}$ with and without intrinsic charm, $A_{\mathrm{in}}=1\%$ and $A_{\mathrm{in}}=0$, via the $g+g$ production mechanism at the After@LHC. Here, contributions from various intermediate diquark states have been summed up.

Figure 3

Comparison of the $y$ distributions for the hadroproduction of ${\mathrm{\Xi }}_{cc}$ with and without the intrinsic charm, $A_{\mathrm{in}}=1\%$ and $A_{\mathrm{in}}=0$, via the $g+g$ production mechanism at the After@LHC. Here, contributions from various intermediate diquark states have been summed up. $p_t>0.2\mathrm{GeV}$.

Figure 4

Comparison of the $x$ distributions for the hadroproduction of ${\mathrm{\Xi }}_{cc}$ with and without intrinsic charm, $A_{\mathrm{in}}=1\%$ and $A_{\mathrm{in}}=0$, via the $g+g$ production mechanism at the After@LHC. Here, contributions from various intermediate diquark states have been summed up. $p_t>0.2\mathrm{GeV}$.

Figure 5

The gluon PDF with and without intrinsic charm, $A_{\mathrm{in}}=1\%$ and $A_{\mathrm{in}}=0$, at different scales (${\mu }^2$).

Figure 6

Scale evolution of the intrinsic charm PDF defined in Eq. (5). $A_{\mathrm{in}}=1\%$.

Figure 7

Total charm PDF defined in Eq. (4) with various intrinsic charm components characterized by $A_{\mathrm{in}}=0\sim 1\%$. ${\mu }^2=5{\mathrm{GeV}}^2$.

Figure 8

The $p_t$ distributions of ${\mathrm{\Xi }}_{cc}$ for various intermediate diquark states at the After@LHC with the intrinsic charm component as $A_{\mathrm{in}}=1\%$, in which no $y$ cut has been applied.

Figure 9

The $y$ distributions of ${\mathrm{\Xi }}_{cc}$ for various intermediate diquark states at the After@LHC with the intrinsic charm component as $A_{\mathrm{in}}=1\%$. $p_t>0.2\mathrm{GeV}$.

Figure 10

The $\eta$ distributions of ${\mathrm{\Xi }}_{cc}$ for various intermediate diquark states at the After@LHC with the intrinsic charm component as $A_{\mathrm{in}}=1\%$. $p_t>0.2\mathrm{GeV}$.

Figure 11

The $x$ distributions of ${\mathrm{\Xi }}_{cc}$ for various intermediate diquark states at the After@LHC with the intrinsic charm component as $A_{\mathrm{in}}=1\%$. $p_t>0.2\mathrm{GeV}$.

Figure 12

The comparison of $p_t$ distributions for the hadroproduction of ${\mathrm{\Xi }}_{cc}$ under different choices of $A_{\mathrm{in}}$ at the After@LHC, where contributions from various production schemes, i.e., ($g+g$), ($g+c$), and ($c+c$), have been summed up. $p_t>0.2\mathrm{GeV}$ and no $y$ cut has been applied.

Figure 13

The comparison of $y$ distributions for the hadroproduction of ${\mathrm{\Xi }}_{cc}$ under different choices of $A_{\mathrm{in}}$ at the After@LHC, where contributions from various production schemes, i.e., ($g+g$), ($g+c$), and ($c+c$), have been summed up. $p_t>0.2\mathrm{GeV}$ and no $y$ cut has been applied.

Figure 14

The comparison of $\eta$ distributions for the hadroproduction of ${\mathrm{\Xi }}_{cc}$ under different choices of $A_{\mathrm{in}}$ at the After@LHC, where contributions from various production schemes, i.e., ($g+g$), ($g+c$), and ($c+c$), have been summed up. $p_t>0.2\mathrm{GeV}$ and no $y$ cut has been applied.

Figure 15

The comparison of $x$ distributions for the hadroproduction of ${\mathrm{\Xi }}_{cc}$ under different choices of $A_{\mathrm{in}}$ at the After@LHC, where contributions from various production schemes, i.e., ($g+g$), ($g+c$), and ($c+c$), have been summed up. $p_t>0.2\mathrm{GeV}$ and no $y$ cut has been applied.

Figure 16

The ${\kappa }_i$ ($i=g+c,c+c$) defined in Eq. (13) versus $p_t$ of ${\mathrm{\Xi }}_{cc}$ with the intrinsic charm component $A_{\mathrm{in}}=1\%$ at the After@LHC, in which contributions from different intermediate diquark states have been summed up. $p_t>0.2\mathrm{GeV}$ and no $y$ cut are applied.

Figure 17

The ${\chi }_i$ ($i=g+c,c+c$) defined in Eq. (14) versus $y$ of ${\mathrm{\Xi }}_{cc}$ with the intrinsic charm component $A_{\mathrm{in}}=1\%$ at the After@LHC, in which contributions from different intermediate diquark states have been summed up. $p_t>0.2\mathrm{GeV}$ and no $y$ cut are applied.