20.500.12556/RUL-186679 Kalibracija simulacije in rekonstrukcije detektorja obročev Čerenkova pri Belle II Calibration of simulation and reconstruction of Aerogel RICH at Belle II V fiziki osnovnih delcev moramo biti zmožni rekonstruirati procese, ki se dogajajo v naših eksperimentih. Pri tem si pomagamo z detektorji za identifikacijo delcev, s katerimi določimo identitete delcev v končnih stanjih. Eden od takih detektorjev pri Belle II je detektor obročev Čerenkova, ki se večinoma uporablja za ločevanje med kaoni in pioni po celotnem kinematskem območju eksperimenta. Za razumevanje procesov v detektorjih in razumevanje podatkov, ki jih iz njih dobimo, si pomagamo s simulacijo, ki dobro poustvari merjene podatke. To ujemanje izboljšamo s kalibracijo posameznih delov simulacije in prilagoditvijo uporabljenih parametrov, kar je prvi cilj tega zaključnega dela. Drugi cilj je natančneje določiti prispevek ozadja za izračun funkcije verjetja, ki jo uporablja rekonstrukcijski algoritem ARICH pri določanju identitete delca. V obeh primerih smo dobili dobre rezultate in izboljšali ujemanje z merjenimi podatki. Za namen kalibracije smo uporabili mione iz $e^+e^- \rightarrow \mu^+\mu^-$ dogodkov, ki se pogosto uporabljajo za kalibracijo detektorjev, prispevke ozadja pa smo preučevali s protoni pod pragom za Čerenkovo sevanje in smo jih morali rekonstruirati sami. Preverili smo tudi učinkovitost ločevanja med kaoni in pioni ter opazili izboljšanje po kalibraciji. When it comes to particle physics experiments, we need to be able to reconstruct processes that happen in our detectors. For that we use detectors capable of identifying charged particles, one of such detectors at Belle II is aerogel RICH, which is mostly used for discriminating between kaons and pions in the whole kinematic region of the experiment. To understand what is happening in our detectors and the measurements that we get, we use simulations which recreate measured data and require calibration to get a good agreement between simulated and measured data. We are able to improve certain aspects of simulations by changing parameters used in them, which is part of this thesis' goal. Second thing we focused on, is improving background contribution for calculating PID likelihoods used by ARICH reconstruction algorithm, in order to achieve better agreement with observed data. We got good results in both of the tasks we set out to do, using common calibration data from $e^+e^- \rightarrow \mu^+\mu^-$ events as well as from reconstructed proton tracks to observe background contributions. For protons, we used tracks below Cherenkov radiation threshold and with them being uncommon for detector calibration studies, we had to reconstruct them ourselves. For each part of the calibration we observed improvement for both different particle types. Lastly, we checked particle identification performance for discriminating between kaons and pions and observed improvement after calibration. Belle II identifikacija delcev Čerenkovo sevanje detektor obročev Čerenkova kalibracija simulacija rekonstrukcija protoni mioni Belle II particle identification Cherenkov radiation RICH detector calibration simulation reconstruction protons muons true false false Slovenski jezik Angleški jezik Zaključna naloga 2026-09-04 08:15:07 2026-09-04 08:15:13 2026-09-05 04:33:56 0000-00-00 00:00:00 2026 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 162623 289909507 23138.pdf 23138.pdf 1 5BD766D67DE5287A72600CBEA9701FB6 58aecdcd2f3ae514a35233ee0386ad5aa1c3dc7c31326652e4a41dbe86cbf033 fdce20aa-a827-11f1-8bc5-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=246001 Fakulteta za matematiko in fiziko 0 0 0