Charm quark and meson production in association with single-jet at the LHC

We discuss charm quark/antiquark and charmed meson production in association with one extra jet (gluon, quark, antiquark) at the LHC. The calculations are performed both in collinear and $k_T$-factorization approaches. Different unintegrated gluon distribution functions are used in the $k_T$-factorization approach. Several predictions for the LHC are presented. We show distributions in rapidity and transverse momenta of $c/\overline{c}$ (or charmed mesons) and the associated jet as well as some two-dimensional observables. Interesting correlation effects are predicted, e.g., in azimuthal angles ${\phi }_{c\overline{c}}$ and ${\phi }_{c-\mathrm{jet}}$. We have also discussed a relation of the $2\to 2$ and $2\to 3$ partonic calculations in the region of large transverse momenta of charm quarks/antiquarks as well as the similarity of the next-to-leading order collinear approach and the $k_T$-factorization approach with the Kimber-Martin-Ryskin unintegrated parton distribution functions. Integrated cross sections for $D^0+\mathrm{jet}$ production for ATLAS detector acceptance and for different cuts on jet transverse momenta are also presented.

Figure 1

A diagrammatic representation of the mechanisms considered for the $pp\to c\overline{c}+\mathrm{jet}$ reaction.

Figure 2

Transverse momentum distribution of the $c$-quark (left panel) and associated jet (right panel) in the collinear approach.

Figure 3

Rapidity distribution of the $c$-quark (left panel) and associated jet (right panel) in the collinear approach.

Figure 4

Distribution in invariant mass of the $c$-quark jet (left panel) and $c\overline{c}$ system (right panel) in the collinear approach.

Figure 5

Distribution in the azimuthal angle between the $c$ quark and jet (left panel) and between $c$ quark and $\overline{c}$ antiquark (right panel) in the collinear approach.

Figure 6

Transverse momentum distribution of the $c$-quark (left panel) and associated jet (right panel) in the $k_T$-factorization approach with different uGDFs.

Figure 7

Rapidity distribution of the $c$-quark (left panel) and associated jet (right panel) in the $k_T$-factorization approach with different uGDFs.

Figure 8

Distribution in invariant mass of the $c$-quark jet (left panel) and $c\overline{c}$ system (right panel) in the $k_T$-factorization approach with different uGDFs.

Figure 9

Distribution in the azimuthal angle between the $c$ quark and jet (left panel) and between $c$ quark and $\overline{c}$ antiquark (right panel) in the $k_T$-factorization approach with different uGDFs.

Figure 10

Two-dimensional distributions in transverse momenta of initial gluons for three different uGDFs specified in the figure caption.

Figure 11

Transverse momentum distribution of the $c$-quark (left panel) and associated jet (right panel) in the $k_T$-factorization approach with the KMR uGDF and the extra cut on initial gluon transverse momenta.

Figure 12

Rapidity distribution of the $c$-quark (left panel) and associated jet (right panel) in the $k_T$-factorization approach with the KMR UGDF and the extra cut on initial gluon transverse momenta.

Figure 13

Distribution in the invariant mass of the $c$-quark jet (left panel) and $c\overline{c}$ system (right panel) in the $k_T$-factorization approach with the KMR uGDF and the extra cut on initial gluon transverse momenta.

Figure 14

Distribution in the azimuthal angle between the $c$ quark and jet (left panel) and between $c$ quark and $\overline{c}$ antiquark (right panel) in the $k_T$-factorization approach with the KMR uGDF and the extra cut on initial gluon transverse momenta.

Figure 15

Comparison of transverse momentum distributions of the $c$-quark (left panel) and associated jet (right panel) for the collinear approach (dotted) and the $k_T$-factorization approach with the KMR uGDF and the extra cut on initial gluon transverse momenta (solid).

Figure 16

Comparison of the rapidity distribution of the $c$-quark (left panel) and associated jet (right panel) in the collinear approach (dotted) and the $k_T$-factorization approach with the KMR uGDF and the extra cut on initial gluon transverse momenta (solid).

Figure 17

Comparison of the distribution in the invariant mass of the $c$-quark jet (left panel) and $c\overline{c}$ system (right panel) in the collinear approach (dotted) and in the $k_T$-factorization approach with the KMR uGDF and the extra cut on initial gluon transverse momenta (solid).

Figure 18

Comparison of the distribution in the azimuthal angle between the $c$ quark and jet (left panel) and between $c$-quark and $\overline{c}$-antiquark (right panel) in the collinear approach (dotted) and in the $k_T$-factorization approach with the KMR uGDF and the extra cut on initial gluon transverse momenta (solid).

Figure 19

Two-dimensional distribution in transverse momenta of the outgoing $c$ quark and $\overline{c}$ antiquark for the collinear and $k_T$-factorization approaches. The details are specified in the figure.

Figure 20

Two-dimensional distribution in transverse momenta of the outgoing $c$ quark and jet for the collinear and $k_T$-factorization approaches. The details are specified in the figure.

Figure 21

Two-dimensional distribution in the relative azimuthal angle between the $c$ quark and $\overline{c}$ antiquark and jet transverse momentum for the collinear and $k_T$-factorization approaches. The details are specified in the figure.

Figure 22

Transverse momentum distribution of $c$ quarks in the collinear (left panel) and $k_T$-factorization (right panel) approaches. We compare results of $2\to 2$ and $2\to 3$ partonic calculations. More detailed discussion is given in the main text.

Figure 23

Azimuthal angle correlation between $D^0$ meson and jet for the collinear and $k_T$-factorization approaches. The cuts are specified in the figure caption.