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$K^+\to \pi^+\nu\bar\nu$

Motivated by the new experimental information reported by the BNL--E787 Collaboration, we analyse the present impact and the future prospects opened by the measurement of $\br(K^+\to\pi^+\nu\bar\nu)$. Although still affected by a large error, the BNL--E787 result favours values of $\br(K^+\to \pi^+\...

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Detalles Bibliográficos
Autores principales: D'Ambrosio, Giancarlo, Isidori, Gino
Lenguaje:eng
Publicado: 2001
Materias:
Acceso en línea:https://dx.doi.org/10.1016/S0370-2693(02)01328-X
http://cds.cern.ch/record/530724
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author D'Ambrosio, Giancarlo
Isidori, Gino
author_facet D'Ambrosio, Giancarlo
Isidori, Gino
author_sort D'Ambrosio, Giancarlo
collection CERN
description Motivated by the new experimental information reported by the BNL--E787 Collaboration, we analyse the present impact and the future prospects opened by the measurement of $\br(K^+\to\pi^+\nu\bar\nu)$. Although still affected by a large error, the BNL--E787 result favours values of $\br(K^+\to \pi^+\nu\bar\nu)$ substantially larger than what expected within the Standard Model. As a result, this data already provide non-trivial constraints on the unitarity triangle, when interpreted within the Standard Model framework. We stress the importance of the clean relation between $\br(K^+\to \pi^+\nu\bar\nu)$, $\sin2\beta$ and $\Delta M_{B_d}/\Delta M_{B_s}$ that in the next few years could provide one of the deepest probes of the Standard Model in the sector of quark-flavour dynamics. A speculative discussion about possible non-standard interpretations of a large $\br(K^+\to \pi^+\nu\bar\nu)$ is also presented. Two main scenarios naturally emerge: those with direct new-physics contributions to the $s \to d \nu\bar\nu$ amplitude and those with direct new-physics effects only in $B_d$--$\bar B_d$ mixing. Realistic models originating these two scenarios and possible future strategies to clearly identify them are briefly discussed.
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institution Organización Europea para la Investigación Nuclear
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publishDate 2001
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spelling cern-5307242023-06-03T02:18:34Zdoi:10.1016/S0370-2693(02)01328-Xhttp://cds.cern.ch/record/530724engD'Ambrosio, GiancarloIsidori, Gino$K^+\to \pi^+\nu\bar\nu$Particle Physics - PhenomenologyMotivated by the new experimental information reported by the BNL--E787 Collaboration, we analyse the present impact and the future prospects opened by the measurement of $\br(K^+\to\pi^+\nu\bar\nu)$. Although still affected by a large error, the BNL--E787 result favours values of $\br(K^+\to \pi^+\nu\bar\nu)$ substantially larger than what expected within the Standard Model. As a result, this data already provide non-trivial constraints on the unitarity triangle, when interpreted within the Standard Model framework. We stress the importance of the clean relation between $\br(K^+\to \pi^+\nu\bar\nu)$, $\sin2\beta$ and $\Delta M_{B_d}/\Delta M_{B_s}$ that in the next few years could provide one of the deepest probes of the Standard Model in the sector of quark-flavour dynamics. A speculative discussion about possible non-standard interpretations of a large $\br(K^+\to \pi^+\nu\bar\nu)$ is also presented. Two main scenarios naturally emerge: those with direct new-physics contributions to the $s \to d \nu\bar\nu$ amplitude and those with direct new-physics effects only in $B_d$--$\bar B_d$ mixing. Realistic models originating these two scenarios and possible future strategies to clearly identify them are briefly discussed.Motivated by the new experimental information reported by the BNL--E787 Collaboration, we analyse the present impact and the future prospects opened by the measurement of $\br(K^+\to\pi^+\nu\bar\nu)$. Although still affected by a large error, the BNL--E787 result favours values of $\br(K^+\to \pi^+\nu\bar\nu)$ substantially larger than what expected within the Standard Model. As a result, this data already provide non-trivial constraints on the unitarity triangle, when interpreted within the Standard Model framework. We stress the importance of the clean relation between $\br(K^+\to \pi^+\nu\bar\nu)$, $\sin2\beta$ and $\Delta M_{B_d}/\Delta M_{B_s}$ that in the next few years could provide one of the deepest probes of the Standard Model in the sector of quark-flavour dynamics. A speculative discussion about possible non-standard interpretations of a large $\br(K^+\to \pi^+\nu\bar\nu)$ is also presented. Two main scenarios naturally emerge: those with direct new-physics contributions to the $s \to d \nu\bar\nu$ amplitude and those with direct new-physics effects only in $B_d$--$\bar B_d$ mixing. Realistic models originating these two scenarios and possible future strategies to clearly identify them are briefly discussed.Motivated by the new experimental information reported by the BNL--E787 Collaboration, we analyse the present impact and the future prospects opened by the measurement of $\br(K^+\to\pi^+\nu\bar\nu)$. Although still affected by a large error, the BNL--E787 result favours values of $\br(K^+\to \pi^+\nu\bar\nu)$ substantially larger than what expected within the Standard Model. As a result, this data already provide non-trivial constraints on the unitarity triangle, when interpreted within the Standard Model framework. We stress the importance of the clean relation between $\br(K^+\to \pi^+\nu\bar\nu)$, $\sin2\beta$ and $\Delta M_{B_d}/\Delta M_{B_s}$ that in the next few years could provide one of the deepest probes of the Standard Model in the sector of quark-flavour dynamics. A speculative discussion about possible non-standard interpretations of a large $\br(K^+\to \pi^+\nu\bar\nu)$ is also presented. Two main scenarios naturally emerge: those with direct new-physics contributions to the $s \to d \nu\bar\nu$ amplitude and those with direct new-physics effects only in $B_d$--$\bar B_d$ mixing. Realistic models originating these two scenarios and possible future strategies to clearly identify them are briefly discussed.Motivated by the new experimental information reported by the BNL-E787 Collaboration, we analyse the present impact and the future prospects opened by the measurement of B (K + →π + ν ν ̄ ) . Although still affected by a large error, the BNL-E787 result favours values of B (K + →π + ν ν ̄ ) substantially larger than what expected within the Standard Model. As a result, this data already provide non-trivial constraints on the unitarity triangle, when interpreted within the Standard Model framework. We stress the importance of the clean relation between B (K + →π + ν ν ̄ ) , sin2 β and ΔM B d / ΔM B s that in the next few years could provide one of the deepest probes of the Standard Model in the sector of quark-flavour dynamics. A speculative discussion about possible non-standard interpretations of a large B (K + →π + ν ν ̄ ) is also presented. Two main scenarios naturally emerge: those with direct new-physics contributions to the s→dν ν ̄ amplitude and those with direct new-physics effects only in B d – B ̄ d mixing. Realistic models originating these two scenarios and possible future strategies to clearly identify them are briefly discussed.hep-ph/0112135CERN-TH-2001-355CERN-TH-2001-355oai:cds.cern.ch:5307242001-12-10
spellingShingle Particle Physics - Phenomenology
D'Ambrosio, Giancarlo
Isidori, Gino
$K^+\to \pi^+\nu\bar\nu$
title $K^+\to \pi^+\nu\bar\nu$
title_full $K^+\to \pi^+\nu\bar\nu$
title_fullStr $K^+\to \pi^+\nu\bar\nu$
title_full_unstemmed $K^+\to \pi^+\nu\bar\nu$
title_short $K^+\to \pi^+\nu\bar\nu$
title_sort $k^+\to \pi^+\nu\bar\nu$
topic Particle Physics - Phenomenology
url https://dx.doi.org/10.1016/S0370-2693(02)01328-X
http://cds.cern.ch/record/530724
work_keys_str_mv AT dambrosiogiancarlo ktopinubarnu
AT isidorigino ktopinubarnu