Search for B^ + →K^ + νν over ¯ Decays Using an Inclusive Tagging Method at Belle II.
| Author | :
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| Abstract | :
A search for the flavor-changing neutral-current decay B^{+}→K^{+}νν[over ¯] is performed at the Belle II experiment at the SuperKEKB asymmetric energy electron-positron collider. The data sample corresponds to an integrated luminosity of 63 fb^{-1} collected at the ϒ(4S) resonance and a sample of 9 fb^{-1} collected at an energy 60 MeV below the resonance. Because the measurable decay signature involves only a single charged kaon, a novel measurement approach is used that exploits not only the properties of the B^{+}→K^{+}νν[over ¯] decay, but also the inclusive properties of the other B meson in the ϒ(4S)→BB[over ¯] event, to suppress the background from other B meson decays and light-quark pair production. This inclusive tagging approach offers a higher signal efficiency compared to previous searches. No significant signal is observed. An upper limit on the branching fraction of B^{+}→K^{+}νν[over ¯] of 4.1×10^{-5} is set at the 90% confidence level. |
| Year of Publication | :
2021
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| Journal | :
Physical review letters
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| Volume | :
127
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| Issue | :
18
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| Number of Pages | :
181802
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| Date Published | :
2021
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| ISSN Number | :
0031-9007
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| URL | :
https://link.aps.org/abstract/PRL/v127/p181802
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| DOI | :
10.1103/PhysRevLett.127.181802
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| Short Title | :
Phys Rev Lett
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