20.500.12556/RUL-178836 Model-agnostic likelihood for the reinterpretation of the $B^+ \to K^+\nu\bar{\nu}$ measurement at Belle II We recently measured the branching fraction of the $B^+ \to K^+\nu\bar{\nu}$⁢ decay using 362  fb$^{-1}$ of on-resonance $e^+e^-$ collision data under the assumption of Standard Model kinematics, providing the first evidence for this decay. To facilitate future reinterpretations and maximize the scientific impact of this measurement, we publicly release the full analysis likelihood along with all necessary material required for reinterpretation under arbitrary theoretical models sensitive to this measurement. In this work, we demonstrate how the measurement can be reinterpreted within the framework of the weak effective theory. Using a kinematic reweighting technique in combination with the published likelihood, we derive marginal posterior distributions for the Wilson coefficients, construct credible intervals, and assess the goodness of fit to the Belle II data. For the weak effective theory Wilson coefficients, the posterior mode of the magnitudes |$C_{\mathrm{VL}}+C_{\mathrm{VR}}$|, |$C_{\mathrm{SL}}+C_{\mathrm{SR}}$|, and |$C_{\mathrm{TL}}$| corresponds to the point (11.3, 0.0, 8.2). The respective 95% credible intervals are [1.9, 16.2], [0.0, 15.4], and [0.0, 11.2]. experimental nuclear physics physics of elementary particles eksperimentalna jedrska fizika fizika osnovnih delcev true false true Angleški jezik Slovenski jezik Članek v reviji 2026-01-30 11:19:36 2026-01-30 11:19:36 2026-03-13 10:48:16 0000-00-00 00:00:00 2025 0 0 Str. 092016-1-092016-10 iss. 9 Vol. 112 Nov. 2025 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 539.1 2470-0010 10.1103/pr66-sd36 266634243 pr66-sd36_(1).pdf pr66-sd36_(1).pdf 1 9C4D2809BC2D6CCA35D29AEA0E1B1F9C 09ed51bf6abef9d04af6514e503be8f114c483b9ba45ede22b69f4da412dc2d6 4cca196e-fdc5-11f0-a1ba-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=226847 https://journals.aps.org/prd/abstract/10.1103/pr66-sd36 0 51cb89db-fdc5-11f0-a1ba-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=226848 Fakulteta za matematiko in fiziko 0 0 0