Search for B^ + →K^ + νν over ¯ Decays Using an Inclusive Tagging Method at Belle II.
| Author | |
| 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 |
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2021
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| Journal |
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Physical review letters
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| Volume |
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127
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| Issue |
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18
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| Number of Pages |
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181802
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| Date Published |
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2021
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| ISSN Number |
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0031-9007
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| URL |
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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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