Karlsruhe 2024 – scientific programme
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T: Fachverband Teilchenphysik
T 125: Flavour physics 6
T 125.1: Talk
Friday, March 8, 2024, 09:00–09:15, Geb. 30.41: HS 4
Search for B→ µ ν at Belle and Belle II — Florian Bernlochner, Jochen Dingfelder, •Daniel Jacobi, and Markus Prim — Physikalisches Institut der Rheinischen Friedrich-Wilhelms-Universität Bonn
The leptonic B meson decay of B→ µ ν is highly CKM- and helicity-suppressed and represents a challenging signature to identify. Its decay rate is extremely sensitive to new physics contributions from leptoquarks or thus far unidentified charged scalar mediators. Within the context of the Standard Model, its discovery also allows for another avenue to determine the Cabibbo-Kobayashi-Matrix element Vub. Due to the two-body nature of the leptonic decay, however, the muon momentum is fixed in the rest frame of the decaying B meson. By boosting muon candidates into this rest frame frame, a better signal resolution and improved sensitivity can be achieved. For this, however, the full e+ e− → B B event needs to be analyzed and the kinematic properties of the accompanying B meson need to be reconstructed. This can be achieved with high efficiency using an inclusive reconstruction approach. We present the current status of a search for B→ µ ν using the full Belle and Run 1 Belle II data set of 1.07 ab−1. Control studies, using B−→ D0[→ K− π+]π− decays illustrate the accuracy of the employed inclusive reconstruction technique of the accompanying B meson information. The signal extraction relies on a full likelihood combination of both data sets, resulting in improved sensitivity.
Keywords: Leptonic; B-Meson; Inclusive; Belle; Belle II