We consider the production of Z bosons associated with heavy (charm and beauty) jets at the LHC energies using two scenarios based on the transverse momentum dependent (TMD) parton densities in a proton. The first of them employs the Catani-Ciafaloni-Fiorani-Marchesini gluon evolution and is implemented in the Monte-Carlo event generator PEGASUS. Here, the heavy quarks are always produced in the hard partonic scattering. The second scheme is based on the parton branching approach, currently implemented into the Monte-Carlo event generator CASCADE. In this scenario, the Z + jets sample is generated and then events containing the heavy flavor jet in a final state are selected. We compare the predictions obtained within these two TMD-based approaches to each other, investigate their sensitivity to the TMD gluon densities in a proton and estimate the effects coming from parton showers and double parton scattering mechanism. Additionally, we compare our predictions with the results of traditional (collinear) pQCD calculations performed at NLO accuracy. It is shown that the TMD-based results agree with the LHC experimental data collected at √(s) = 8 and 13 TeV. We discuss the sensitivity of observables to the quark distributions in a proton and present predictions to search for the intrinsic charm signal in forthcoming analyses of the LHC experimental data.

Recent results from the ATLAS experiment at the LHC on the charmonium production and on the B-c production and decays are presented. These include studies of the associated production of the J/psi meson and W boson, the measurement of J/psi and psi(2S) mesons differential production cross-sections, the measurement of the differential ratios of the B-c(+) and B+ production crosssections, and the new results on the B-c(+) decays to J/psi D-s((*)) final states. The results are obtained with pp collision data collected at centre-of-mass energies root s= 8 and 13 TeV.

This proceeding contribution presents the recent highlights of charm physics programme of the ATLAS experiment at the Large Hadron Collider. These include measurements of charmonia production both inppand nuclear collisions, charmonium pair production, studies of exotic states andBcmesons. Most of the shown results are obtained with the data collected during the LHC Run-1.

The cross section of associated production of a Z boson with heavy flavor jets in $pp$ collisions is calculated using the SHERPA Monte Carlo generator and the analytical combined QCD approach based on kt-factorization at small x and conventional collinear QCD at large x. A satisfactory description of the ATLAS and CMS data on the $p_T$ spectra of Z bosons and c-jets in the whole rapidity, y, region is shown. Searching for the intrinsic charm (IC) contribution in these processes, which could be visible at large y > 1.5, we study observables very sensitive to non-zero IC contributions and less affected by theoretical QCD scale uncertainties. One of such observables is the so-called double ratio: the ratio of the differential cross section of Z + c production in the central region of |y| < 1.5 and in the forward region 1.5 < |y| < 2.5, divided by the same ratio for Z + b production. These observables could be more promising for the search of IC at LHC as compared to the observables considered earlier.

The Flavour Changing Neutral Current processes are sensitive to New Physics contributions, in particular through additional electroweak loop amplitudes. The angular analysis of the decay of B 0 → μ + μ − K* 0 is presented. A number of angular coefficients are measured as a function of the invariant mass squared of the dimuon system using data collected by the ATLAS experiment at the LHC. Comparison is made to theoretical predictions, including for the observable P ′ 5 , for which there has been recent tension between theory and experiment. ATLAS result on the study of the B ( s ) 0 → μ + μ − rare decays is also presented.

This paper presents an overview of muon trigger and B-physics trigger of the ATLAS experiment. Main updates done during the preparation for Run 2 data-taking are outlined. Trigger performance results obtained with new experimental data and modelling are shown.

Processes leading to b-quark production at the LHC energies are simulated by using the Pythia generator. For proton-proton interactions at 7 and 14 TeV, the cross sections for b-quark production are evaluated for three mechanisms that are taken into account in the Pythia generator. These are quark-pair production, the excitation of sea quarks, and gluon splitting. Correlations of azimuthal angles of b-quark emission and properties of accompanying particles in events induced by the various mechanisms of b-quark production are calculated. The results are compared with data from the CDF experiment.