000004456 001__ 4456
000004456 005__ 20240802200919.0
000004456 037__ $$aBELLE2-PTHESIS-2024-015
000004456 041__ $$aeng
000004456 100__ $$aGéraldine Räuber
000004456 245__ $$aMeasurement of |Vus| using hadronic τ decays at Belle II
000004456 260__ $$aVienna$$bHEPHY$$c2024
000004456 300__ $$a186
000004456 500__ $$aPresented on 14 06 2024
000004456 502__ $$aPhD$$bVienna, TU Wien: Technische Universität Wien$$c2024
000004456 520__ $$aThis thesis presents a precise measurement of the CKM matrix element Vus using data collected at the Belle II experiment situated at the SuperKEKB electron- positron collider in Tsukuba, Japan. The measurement employs the ratio of branching fractions of tau lepton decays, denoted as RK/π, with both pion and kaon mesons in the final state, given by RK/π = B(τ− → K−ντ)/B(τ− → π−ντ). Selection criteria involve a tag side consisting of three charged particles, defining an overall 3×1- prong topology. The preliminary obtained result, RK/π = 0.06438 ± 0.00080, corre- sponds to a |Vus| value of 0.2229±0.0017, and takes into account only the main systematic uncertainty sources. Recognizing the systematic nature of this measurement, a dedicated study addressing leading systematic uncertainties is undertaken. Specifically, a performance assessment of pion identification corrections is conducted to enhance the reliability and precision of the measurement.
000004456 700__ $$aChristoph Schwanda$$edir.
000004456 700__ $$aGianluca Inguglia$$edir.
000004456 8560_ $$fgeraldine.raeuber@oeaw.ac.at
000004456 8564_ $$uhttps://docs.belle2.org/record/4456/files/BELLE2-PTHESIS-2024-015.pdf
000004456 980__ $$aTHESIS