000002330 001__ 2330
000002330 005__ 20210407184332.0
000002330 037__ $$aBELLE2-TALK-CONF-2021-018
000002330 041__ $$aeng
000002330 088__ $$aBELLE2-TALK-DRAFT-2021-029
000002330 100__ $$aFilippo Dattola
000002330 245__ $$aSearch for B+ => K+ nu nubar
000002330 260__ $$aRencontres de Moriond 2021 - Electroweak Interactions & Unified Theories$$c2021-03-20
000002330 300__ $$amult. p
000002330 520__ $$aA search for the flavour-changing neutral current decay B+ → K+ ν ν is performed with an electron-positron collision data sample corresponding to 63fb−1 collected at the Υ(4S) resonance by the Belle II experiment. A novel measurement method is developed, which exploits topological properties of the decay that differ from both generic bottom-meson decays and light-quark pair-production. This inclusive tagging approach has the benefit of a higher signal efficiency compared to previous searches for this rare decay. As no significant signal is observed, an upper limit on the branching fraction of B+ → K+ ν ν of 4.4 × 10−5 is set at the 90% confidence level.
000002330 8560_ $$fdjaffe@bnl.gov
000002330 8564_ $$uhttps://docs.belle2.org/record/2330/files/BELLE2-TALK-CONF-2021-018.pdf