SEARCH FOR B+ → K+νν DECAYS WITH AN INCLUSIVE TAGGING METHOD AT THE BELLE II EXPERIMENT

Sumitted to PubDB: 2021-05-12

Category: Proceeding, Visibility: Public

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Authors	Filippo Dattola
Date	May 12, 2021
Belle II Number	BELLE2-CONF-PROC-2021-016
Abstract	This contribution illustrates a new search for the flavor-changing neutral-current decay B+ → K+νν performed by the Belle II experiment at the SuperKEKB asymmetric-energy electron-positron collider. In this study, a sample corresponding to an integrated luminosity of 63 fb−1 collected at the Υ(4S) resonance and an additional sample of 9 fb−1 collected at an energy 60 MeV below the resonance are used. A novel technique, based on an inclusive tagging method and exploiting the topological features of the B+ → K+νν decay, is employed and it provides a higher signal efficiency with respect to the methods used in the previous searches. No significant signal is observed. An upper limit of 4.1 × 10−5 is set on the B+ → K+νν branching fraction at the 90 % confidence level.