Measurement of the very rare <it>K</it>(+)<it>-></it><mml:msup>pi+</mml:msup>nu nu<mml:mo stretchy="true"><overbar></mml:mover> decay

Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F21%3A10439669" target="_blank" >RIV/00216208:11320/21:10439669 - isvavai.cz</a>
Result on the web
<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=f1bqHid_D" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=f1bqHid_D</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1007/JHEP06(2021)093" target="_blank" >10.1007/JHEP06(2021)093</a>

Result language
angličtina
Original language name
Measurement of the very rare <it>K</it>(+)<it>-></it><mml:msup>pi+</mml:msup>nu nu<mml:mo stretchy="true"><overbar></mml:mover> decay
Original language description
The NA62 experiment reports the branching ratio measurement BR<mml:mfenced close=")" open="(">K+-> pi+nu nu <overbar></mml:mover></mml:mfenced>=<mml:mfenced close=")" open="(">10.6-3.4+4.0</mml:msubsup><mml:mfenced open="|">stat</mml:mfenced>+/- <mml:msub>0.9syst</mml:mfenced>x10-11 at 68% CL, based on the observation of 20 signal candidates with an expected background of 7.0 events from the total data sample collected at the CERN SPS during 2016-2018. This provides evidence for the very rare K+-> pi+nu <mml:mover accent="true">nu <mml:mo stretchy="true"><overbar></mml:mover> decay, observed with a significance of 3.4 sigma. The experiment achieves a single event sensitivity of (0.839 +/- 0.054) x 10(-11), corresponding to 10.0 events assuming the Standard Model branching ratio of (8.4 +/- 1.0) x 10(-11). This measurement is also used to set limits on BR(K+-> pi X+), where X is a scalar or pseudo-scalar particle. Details are given of the analysis of the 2018 data sample, which corresponds to about 80% of the total data sample.
Czech name
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Czech description
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Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10300 - Physical sciences

Project
<a href="/en/project/LTT17018" target="_blank" >LTT17018: Getting new knowledge of the microworld using the CERN infrastructure</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year
2021
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

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