Produkce identifikovaných hadronů v hluboce nepružném rozptylu na experimentu COMPASS

• Thesis title in Czech: Produkce identifikovaných hadronů v hluboce nepružném rozptylu na experimentu COMPASS
• Thesis title in English: Identified hadron production in deep-inelastic scattering at COMPASS
• Key words: DIS|SIDIS|COMPASS|struktura nukleonu|TMD PDF|RICH|identifikace hadronů
• English key words: DIS|SIDIS|COMPASS|nucleon structure|TMD PDF|RICH|hadron identification
• Academic year of topic announcement: 2023/2024
• Thesis type: diploma thesis
• Department: Department of Low Temperature Physics (32-KFNT)
• Supervisor: Mgr. Jan Matoušek, Ph.D.
• Author: Bc. Vendula Benešová - assigned and confirmed by the Study Dept.
• Date of registration: 18.02.2024
• Date of assignment: 19.02.2024
• Confirmed by Study dept. on: 19.02.2024
• Date and time of defence: 05.06.2025 09:00
• Date of electronic submission: 01.05.2025
• Opponents: Mgr. Petr Baroň, Ph.D.

Guidelines

- Study the ring-imaging Cherenkov (RICH) detector of COMPASS. Learn about the used analysis routines and its past performance.
- Evaluate and try to optimize the efficiency and purity of the RICH in hadron identification (using decays of rho, phi, and lambda particles).
- Optionally, test the possibility to use calorimetry to suppress electrons and positrons in the hadron sample.
- Study the distributions of identified hadrons in deep-inelastic scattering (DIS). Measure the multiplicity as a function of the transverse momentum as well as the azimuthal distribution of the hadrons.
- Optionally, study distributions of decaying neutral hadrons, such as rho0, phi, or K0, produced in DIS.
- Interpret the results in terms of transverse-momentum dependent PDFs and fragmentation functions.

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, Collins and Sivers asymmetries in muonproduction of pions and kaons off transversely polarised proton, Phys. Lett. B 744, 2015, http://arxiv.org/abs/arXiv:1408.4405
- 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
- A. Moretti: Study of the Transverse-Momentum-Dependent structure of the nucleon in Semi-Inclusive DIS, PhD thesis, University of Trieste, 2021, https://wwwcompass.cern.ch/compass/publications/theses/2021_phd_moretti.pdf
- PHAST: PHysics Analysis Software Tools. http://ges.web.cern.ch/ges/phast/index.html.
- ROOT data analysis framework. https://root.cern.ch/.

Preliminary scope of work in English

This work would be a continuation of the studies described in [V. Benešová, Hadron production in deep inelastic scattering of muons off protons at COMPASS experiment, Bachelor thesis, Charles University, 2023]. It would extend it by studying the distributions of hadrons as a function of their transverse momentum and especially by hadron identification. To better understand the complicated picture of the DIS, it is desirable to carry out a fully multi-dimensional measurement for identified hadron species (pi, K, p). One could also study the possibility to measure neutral pions and kaons and vector mesons such as rho from their decays. The large data sample collected by COMPASS in 2016-2017 on liquid hydrogen target allows such a measurement. The data collected in 2022 on polarised deuterium give in addition access to spin-dependent TMD PDFs, such as the polarisation of quarks in a transversely polarised nucleon (so-called transversity PDF) and the correlation between quark transverse momentum and nucleon transverse polarisation (Sivers TMD PDF). The comparison of the same observables on the proton (2016-2017) and isoscalar (2022) targets measured on the same apparatus and analysed within the same framework could also, together with the hadron identification, uncover possible differences in the distributions of quarks of different flavours.