Glimpse of a Rare B Decay with Two Invisible Neutrinos at Belle II

Wednesday 21 Feb 2024, 16:00 → 17:00 Europe/London

Slavomira Stefkova (Karlsruhe Institute of Technology)

The decay of B+→K+νν̄ is mediated by flavor-changing neutral current. In the Standard Model, the rate for this elusive process is predicted to be 6×10^-6,  while enhancements are foreseen in many New Physics scenarios. 

Searching for B+→K+νν̄ decays is, however, experimentally challenging as this decay is not only rare but also contains two neutrinos, leaving no signature in the detector. In this colloquium, I will show you details of the newest measurement of the rate of B+→K+νν̄ decays, which is based on 362 fb^-1 of SuperKEKB electron-positron collision data collected at the Upsilon(4S) resonance by the Belle II experiment in Tsukuba, Japan. Using two different but complementary reconstruction techniques, we found, for the first time, evidence for the B+→K+νν̄ process. At the end of my colloquium, I will also highlight future opportunities in B-decays with invisible signatures.

1 Glimpse of a Rare B Decay with Two Invisible Neutrinos at Belle II

Speaker: Slavomira Stefkova

Seminar_Bristol_Stefkova_Feb2024_final.pdf