Florian Bernlochner, ; Jochen Dingfelder, ; Anna-Maria Heyn, ; Markus Prim, ; Munira Khan

26 February 2024
DPG 2024

Abstract: The ratio of the ϒ(4𝑆) → 𝐵+𝐵− and ϒ(4𝑆) → 𝐵0 ¯𝐵0 decay rates, 𝑅±0, represents a crucial input quantity to convert measured yields into branching fractions at 𝑒+𝑒− 𝐵-factory experiments. The most precise present day determinations rely on isospin assumptions. We present the status of a novel approach to determine the 𝐵± and 𝐵0 production fraction using an inclusive approach. It relies on analyzing the reconstructed number of charged tracks in a collision event. On average the decay of two 𝐵 mesons results in about 10 charged final state particles and if perfectly reconstructed, the number of charged tracks from 𝐵± and 𝐵0 differ by two. In this talk, we explore the experimental feasibility to determine 𝑅±0 from a careful analysis of the number of charged tracks in a collision event. Contributions from continuum processes are suppressed using multivariate methods and the template shapes on the number of charged tracks are determined using fully hadronic control channels of self-tagging decays.

Keyword(s): Experimental Flavor Physics; ; Belle II; ; Branching Fraction Measurements