Speaker
Rafal Maciula
(Institute of Nuclear Physics PAN)
Description
Part 1:
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We discuss production of charmed mesons in proton-proton collisions at the LHC. The cross section for inclusive production of $c \bar c$ pairs is calculated in the framework of the $k_{\perp}$-factorization approach. Taking wide range of $x$ values necessary for the calculation we use and test several unintegrated gluon distributions from the literature. Some of them include effect of small-$x$ saturation and fullfil Balitsky-Kovchegov evolution equation. Theoretical uncertainties of the model related to the choice of renormalization and factorization scales as well as due to the quark mass are also discussed. Results of the $k_{\perp}$-factorization approach are compared to NLO parton model and FONLL predictions. The hadronization of charm quarks is included with the help of
different fragmentation functions found for the production of charm in $e^+ e^-$ collisions. Sensitivity of our predictions to the choice of the model of fragmentation is also shown. Inclusive differential distributions in transverse momentum and (pseudo)rapidity of several
charmed mesons ($D^0$, $D^{\pm}$,$D^{*\pm}$,$D^{\pm}_{S}$) will be presented and compared to recent results of the ALICE, ATLAS
and LHCb collaborations. Furthermore, we also consider production of different pairs of charmed mesons ($D^0 {\bar D}^0$, $D^0 D^-$, $D^+ D^{-}_{S}$ etc.) in unique kinematics of forward rapidities of the LHCb experiment. Kinematical correlations in azimuthal angle $\varphi_{D\bar D}$ and invariant mass $M_{D \bar D}$ distributions are presented and compared to LHCb data.
Part 2:
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We discuss production of electrons/muons from semileptonic decays of charm and bottom mesons in proton-proton collisions at the LHC. The cross section for inclusive production of $c \bar c$ and $b \bar b$ pairs is calculated in the framework of the $k_{\perp}$-factorization approach. Here, the KMR and Jung unintegrated gluon distribution functions, used recently for description of charm and bottom cross sections at the LHC, are applied. Theoretical uncertainties of the model related to the choice of renormalization and factorization scales as well as due to the quark mass are also discussed. Results from the $k_{\perp}$-factorization approach are compared to FONLL predictions. The hadronization of charm and bottom quarks is included with the help of the Peterson fragmentation functions. The semileptonic decay functions found by fitting recent semileptonic data obtained by the CLEO and BABAR collaborations are used. In this context some effects of non-zero motion of D and B mesons in the laboratory frame and related modifiactions of the decay functions are also discussed. Inclusive differential distributions in transverse momentum and (pseudo)rapidity of leptons for several kinematical regions will be presented and compared to recent results of the ALICE, ATLAS and CMS collaborations. Furthermore, kinematical correlations between two leptons are also studied, including invariant mass spectra.
Author
Rafal Maciula
(Institute of Nuclear Physics PAN)
Co-author
Antoni Szczurek
(Institute of Nuclear Physics)
