Evidence for B+ → K+ ν¯ν decays
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F24%3A10494120" target="_blank" >RIV/00216208:11320/24:10494120 - isvavai.cz</a>
Result on the web
<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=rm2BRxeoQy" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=rm2BRxeoQy</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1103/PhysRevD.109.112006" target="_blank" >10.1103/PhysRevD.109.112006</a>
Alternative languages
Result language
angličtina
Original language name
Evidence for B+ → K+ ν¯ν decays
Original language description
We search for the rare decay Bþ RIGHTWARDS ARROW Kþν-ν in a 362 fb-1 sample of electron-positron collisions at theϒð4SÞ resonance collected with the Belle II detector at the SuperKEKB collider. We use the inclusiveproperties of the accompanying B meson in ϒð4SÞ RIGHTWARDS ARROW BB- events to suppress background from other decaysof the signal B candidate and light-quark pair production. We validate the measurement with an auxiliaryanalysis based on a conventional hadronic reconstruction of the accompanying B meson. For backgroundsuppression, we exploit distinct signal features using machine learning methods tuned with simulated data.The signal-reconstruction efficiency and background suppression are validated through various controlchannels. The branching fraction is extracted in a maximum likelihood fit. Our inclusive and hadronicanalyses yield consistent results for the Bþ RIGHTWARDS ARROW Kþν-ν branching fraction of 1/22.7 0.5ðstatÞ 0.5ðsystÞ x10-5 and 1/21.1þ0.9-0.8ðstatÞþ0.8-0.5ðsystÞ x 10-5, respectively. Combining the results, we determine the branchingfraction of the decay Bþ RIGHTWARDS ARROW Kþν-ν to be 1/22.3 0.5ðstatÞþ0.5-0.4ðsystÞ x 10-5, providing the first evidence forthis decay at 3.5 standard deviations. The combined result is 2.7 standard deviations above the standardmodel expectation.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
—
OECD FORD branch
10300 - Physical sciences
Result continuities
Project
<a href="/en/project/GA22-18469S" target="_blank" >GA22-18469S: Studies of the Beyond Standard Model phenomena in the flavor sector with the Belle II Experiment</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Others
Publication year
2024
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Physical Review D
ISSN
2470-0010
e-ISSN
2470-0029
Volume of the periodical
109
Issue of the periodical within the volume
11
Country of publishing house
US - UNITED STATES
Number of pages
29
Pages from-to
112006
UT code for WoS article
001270351400001
EID of the result in the Scopus database
2-s2.0-85195461944