Speaker
Description
A brief overview of the experimental evidence for the non-zero intrinsic charm (IC) contribution to the proton PDF is presented. The effect of intrinsic heavy quarks on the production of vector bosons accompanied by $c$ and $b$ jets in $pp$ collisions at the LHC is then investigated. The calculations are performed within the combined QCD approach, based on $k_T$-factorization at small transverse momenta and the use of collinear QCD factorization for the production of Z-bosons and heavy quark jets at large $p_T$. It is shown that the CMS data on the $p_T$ spectra of $Z$ and a charm-jet can be satisfactorily described in the rapidity region $|y|\leq 2.5$ without inclusion of the IC components. However, in the forward kinematical region, $1.5 \leq |y| \leq 2.5$, the IC signal becomes sizable at $p_T > 100$ GeV/$c$. We also predict a significant enhancement in the distribution of charm jets as a function of $\Delta y=|y_Z - y_c|,$ where $y_Z$ and $y_c$ are the rapidities of the Z-boson and the charm jet, respectively. Moreover, it is shown that charm jet production increases significantly at $x_F > 0.2$ when the IC component in the proton PDF is taken into account. We also highlight tests of the $c(x) $ vs. $\bar c(x)$ intrinsic charm asymmetry predicted by LGTH.
