Production of $χ_c$ pairs in $k_T$-factorization

Anna Cisek; Wolfgang Schäfer; Antoni Szczurek

Paper

Production of $χ_c$ pairs in $k_T$-factorization

Abstract

We calculate the production of pairs of

mesons with all possible combinations of

. The leading order production mechanism is the crossed-channel gluon exchange in the gluon-gluon fusion reaction. The building blocks are the vertices

for off shell gluons. We stick to the color-singlet model and calculate the gluon fusion vertices in the limit of heavy quarks with nonrelativistic motion in the bound state. These vertices are used to construct the

amplitudes. We then calculate hadron-level cross sections using the

-factorization approach. In our numerical predictions, we use the KMR-type unintegrated gluon distributions. Several differential distributions at the

center of mass energy

are shown. The salient feature of the

and

-channel gluon exchange are the broad distributions in rapidity difference

between

mesons.