Dalseno, Jeremy2022-08-302022-08-302022The European Physical Journal Plus 137, 806 (2022). https://doi.org/10.1140/epjp/s13360-022-03008-8http://hdl.handle.net/10347/29183A rescaling of the SU(2) isospin triangles constraining ϕ2 (α) that relies on measurements of the experimentally cleaner relative branching fractions, as opposed to those absolute, is proposed. Paving the way towards more systematically sustainable analysis, this method promises to eliminate a dominant systematic at Belle II amongst others, namely the uncertainty on the number of BB¯ pairs in data. Furthermore, a ϕ2 constraint in the B→ρρ system at LHCb that is more independent of Belle II input is shown to become viable even without a measurement of CP violation in B0→ρ+ρ−eng© The Author(s) 2022. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/Atribución 4.0 Internacionalhttp://creativecommons.org/licenses/by/4.0/journal article10.1140/epjp/s13360-022-03008-82190-5444open access