000004569 001__ 4569
000004569 005__ 20241022142705.0
000004569 037__ $$aBELLE2-MTHESIS-2024-022
000004569 041__ $$aeng
000004569 100__ $$aErmes Aviano
000004569 245__ $$aStudy of the reconstruction efficiency of π0 mesons from decays of the lepton τ at the Belle II experiment
000004569 260__ $$aTrieste$$bUniversità degli Studi di Trieste$$c2024
000004569 300__ $$amult. p
000004569 500__ $$aPresented on 18 10 2024
000004569 502__ $$aMSc$$bTrieste, Università degli Studi di Trieste$$c2024
000004569 520__ $$aThis experimental particle-physics thesis explores a novel approach to the determination of the π0 meson reconstruction efficiency, whose uncertainty is a significant limitation in measurements sensitive to beyond Standard Model physics. I aim to determine the π0 reconstruction efficiency by comparing the rates of τ− → π− π^0 ντ with τ− → π− ντ decays recorded with the Belle II detector in SuperKEKB electron-positron collisions. Since these decays have large branching fractions known with high precision, have little background, and cover a wide range in π0 momentum, this approach would enable a reduction of the uncertainty on the π0 efficiency by up to a factor of three over current determinations. I develop the method starting from a simplified simulated sample comprising τ-pairs only and validate it against samples of known efficiency. Next, I extend the study to a fully realistic simulated sample, demonstrating the feasibility and performance of the method in realistic conditions. Finally, I briefly discuss various aspects of the applicability of the method to data. The results demonstrate that the π0 efficiency approach conceptually works and yields performances superior to existing Belle II methods.
000004569 700__ $$aDiego Tonelli$$edir.
000004569 700__ $$aBenigno Gobbo$$edir.
000004569 700__ $$aSebastiano Raiz$$edir.
000004569 8560_ $$fermes.aviano@studenti.units.it
000004569 8564_ $$uhttps://docs.belle2.org/record/4569/files/BELLE2-MTHESIS-2024-022.pdf
000004569 980__ $$aTHESIS