Studium struktury hadronů prostřednictvím procesů DIS a Drell-Yan
| Thesis title in Czech: | Studium struktury hadronů prostřednictvím procesů DIS a Drell-Yan |
|---|---|
| Thesis title in English: | Hadron structure studies via DIS and Drell-Yan processes |
| Key words: | DIS|SIDIS|TMD PDF|RICH|Drell-Yan|struktura hadronu |
| English key words: | DIS|SIDIS|TMD PDF|RICH|Drell-Yan|hadron structure |
| Academic year of topic announcement: | 2025/2026 |
| Thesis type: | dissertation |
| Thesis language: | |
| Department: | Department of Low Temperature Physics (32-KFNT) |
| Supervisor: | Mgr. Jan Matoušek, Ph.D. |
| Author: |
| Guidelines |
| - Study the distributions of hadrons in deep-inelastic scattering (DIS) at COMPASS. Measure the multiplicity as a function of the transverse momentum as well as the azimuthal distribution of the hadrons.
- Try to improve the methods developed for the proton target data and apply them to the isoscalar target DIS data from 2022. - In particular: - try to improve RICH reconstruction by optimising the likelihood fit, perhaps removing backgrounds with a neural network. - prepare Monte Carlo simulations of the 2022 setup modifying the earlier setups. - Interpret the results in terms of transverse-momentum dependent PDFs and fragmentation functions. - Prepare simulations for future Drell-Yan experiments (AMBER or LHCspin), with the goal to optimise the setups and check the feasibility of the experiments. |
| References |
| - COMPASS Collaboration: The Compass Experiment at CERN, Nucl. Instr. Meth. 577, 2007, http://arxiv.org/abs/hep-ex/0703049.
- COMPASS Collaboration: Measurement of azimuthal hadron asymmetries in semi-inclusive deep inelastic scattering off unpolarised nucleons, Nucl. Phys. B 886, 2014, http://arxiv.org/abs/arXiv:1401.6284 - COMPASS Collaboration: Transverse-momentum-dependent multiplicities of charged hadrons in muon-deuteron deep inelastic scattering, Phys. Rev. D 97, 2018, http://arxiv.org/abs/1709.07374 - C. Chatterjee, Performance study of the RICH at COMPASS experiment for hadron identification in SIDIS physics, University of Trieste, 2020, https://wwwcompass.cern.ch/compass/publications/theses/2020_phd_chatterjee.pdf - COMPASS, High-statistics measurement of Collins and Sivers asymmetries for transversely polarised deuterons, Phys. Rev. Lett. 133 (2024) 101903, DOI: 10.1103/PhysRevLett.133.101903, CERN-EP-2023-308, https://inspirehep.net/arxiv/2401.00309. - S. Arnold, A. Metz, and M. Schlegel, “Dilepton production from polarized hadron-hadron collisions,” Phys. Rev. D79 (2009) 034005, arXiv:0809.2262 [hep-ph]. - B. Adams et al., “Letter of Intent: A New QCD facility at the M2 beam line of the CERN SPS (COMPASS++/AMBER),” Tech. Rep. CERN-SPSC-2019-003, SPSC-I-250, CERN, Geneva, Switzerland, 2018. arXiv:1808.00848 [hep-ex]. - F. Metzger et al., “Kaon beam simulations employing conventional hadron beam concepts and the RF separation technique at the CERN M2 beamline for the future AMBER experiment,” JACoW IPAC2023 (2023) TUPM070. - A. Accardi, et al., "LHCspin: a Polarized Gas Target for LHC", CERN-PBC-Notes-2025-008, [arXiv:2504.16034 [hep-ex]]. |
| Preliminary scope of work in English |
| The hadron structure is determined by the QCD, yet it cannot be calculated from the first principles due to its non-perturbative nature at low energies. In inelastic particle collisions, the hadron structure is described by parton distribution functions (PDFs), which need to be measured but are universal among different processes.
COMPASS experiment at CERN collected a unique data set on deep inelastic scattering (DIS) of muons off a transversely polarised deuteron target in 2022. DIS is a powerful tool to access parton distribution functions that describe the proton and neutron structure in the context of inelastic high-energy collisions. While the analysis of the observables depending on the target polarisation is being finalised, accessing polarisation-independent ones requires a precise Monte Carlo model of the apparatus, treatment of backgrounds, and corrections for QED radiative effects. Overcoming these obstacles allows one to access the transverse momentum and azimuthal angle distributions of final-state hadrons. These results, combined with those from a proton target soon to be published, and with other world data, could reveal the transverse momentum and polarisation of quarks within the proton and neutron. New experiments are being prepared at CERN: AMBER is aiming to access the pion sea quark PDF by studying the Drell-Yan production of muon pairs in pion-nucleon scattering, and as the first one after NA2 access the kaon PDFs. It should also be able to check the violation of the Lam-Tung rule, which can also be studied in existing COMPASS data. The LHCspin project proposes to insert a polarised gas target in front of the LHCb detector into the LHC beam. Such a bold design would allow accessing a unique kinematic region between the lower-energy fixed targets and colliders, complementing the electron-proton EIC that is being built in the US. A polarimeter calibration setup may appear in the LHC beam as soon as 2030, perhaps already bringing physics results. The study may be conducted in cooperation with University of Trieste in the framework of a 'cotutelle' agreement. |