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Multiplicities of hadrons in deep-inelastic scattering of muons on nucleons at COMPASS

Abstract : One of the goals of the COMPASS collaboration is the study of the nucleon spin structure. The question of the polarization of the sea quark is a burning issue in the hadronic physics, especially for the strange quark polarization. In order to better constrain the quark polarization, a precise knowledge of the quark Fragmentation Functions (FFs) into hadrons, which are the final state hadronisation of quark q into hadron h, is mandatory. The FFs can be extracted from hadron multiplicities produced in Semi-Inclusive Deep Inelastic Scattering (SIDIS). Data were taken at COMPASS from a 160 GeV/c muon beam scattering off a pure proton target (1H₂). This thesis presents the measurement of charged hadrons (pions, kaons and protons) multiplicities from SIDIS data collected in 2016. It also details the improvements brought to the DJANGOH event generator to better describe the inclusive and semi-inclusive radiative corrections in DIS that are then used as correction factors to the multiplicities. The data cover a large kinematical range : Q² > 1 (GeV/c)², y ε [0.1,0.7], x ε [0.004,0.4], W ε [5,17] GeV et z ε [0.2,0.85]. These multiplicities, which represent about 1800 data points in total, provide an important input for global QCD fit of world data at NLO, aiming at the FFs determination. The quark FFs into kaons are particularly awaited as they can better constrain the strange quark polarization.
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Submitted on : Tuesday, September 10, 2019 - 4:14:07 PM
Last modification on : Friday, May 29, 2020 - 3:51:36 AM
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  • HAL Id : tel-02283265, version 1



Nicolas Pierre. Multiplicities of hadrons in deep-inelastic scattering of muons on nucleons at COMPASS. Nuclear Experiment [nucl-ex]. Université Paris-Saclay; Johannes Gutenberg-Universität Mainz, 2019. English. ⟨NNT : 2019SACLS183⟩. ⟨tel-02283265⟩



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