Studio esplorativo della produzione di heavy quark nella regione del continuo della spettro di dimuone in collisioni p-p a sqrt(s)=13 TeV misurate da ALICE

Heavy quarks, and in particular charm and bottom can be used as a tool to investigate the perturbative QCD sector since their heavy masses act like a cut-off scale in perturbation series. The Large Hadron Collider (LHC), one of the most important facilities investigating Standard Model predictions in hadronic collisions, is an ideal machine for these studies. Among the several experiments located at LHC, ALICE is mainly dedicated to the study of Quark-Gluon Plasma (QGP), an extended system of quarks and gluons in thermal equilibrium, through ultrarelativistic heavy-ion collisions. The ALICE experiment also studies proton-proton (pp) collisions, to explore fundamental aspects of QCD in elementary interactions. Heavy Flavour (HF) hadrons, containing at least one heavy quark, either charm (c) or beauty (b), are among the most important tools for these investigations, as both the production cross-section of the heavy quark pair and its subsequent hadronization to final hadronic states can be accurately estimated. In addition, data on HF production in pp serves as a reference for their production studies in heavy-ion collisions, where QGP formation leads to strong effects on their kinematic distributions. HF hadrons are generally produced in pairs by the hadronisation of quark-antiquark couples. They can be detected via several decay channels, and among them, by studying the production of unlike-sign muon pairs (dimuons) created in their semi-leptonic decays. My thesis work aims at exploring heavy quark production, studying, for the first time in ALICE, the continuum region of the dimuon invariant mass spectrum beyond 4 GeV/c^(2). The performed analysis uses one of the data samples collected by ALICE in p-p collisions at sqrt(s)=13 TeV, in 2018. In the continuum region, semi-leptonic decays of HF represents the main contributing physics process, with a smaller contribution related to the combinatorial background produced in pion and kaon decays and to the Drell-Yan process. HF hadrons were already studied by ALICE in the midrapidity region (|y|<0.5) via their hadronic decay, while this analysis is performed in the region covered by the ALICE muon spectrometer, 2.5<y<4. In the exploratory analysis discussed in this thesis, the raw dimuon spectra measured by ALICE are corrected for the product of acceptance and detection efficiency, assuming that the dimuon acceptance can be factorized as the product of the acceptances of the two detected muons. Then, the spectra are normalized to the number of inelastic pp interactions registered in the period under study, correcting for the bias related to the use of a dimuon trigger in the data taking. The PYTHIA8 Monte-Carlo event generator is then used in this work to provide a first estimate of the contribution to the dimuon spectrum coming from cc and bb pairs in the continuum region. Preliminary analyses testing different possible PYTHIA8 settings have been carried out, comparing the calculated HF yield with previous measurements performed at ALICE and LHCb through the hadronic decay channel. After this step, the PYTHIA8 dimuon invariant mass and transverse momentum distributions have been obtained and compared with the ALICE data. The performed comparison shows that heavy-quark pairs are the dominant contribution to the dimuon spectrum in the continuum region, with $\sim 70$\% of the dimuon yield being due to the decay of prompt open charm hadrons