Understanding the first measurement of $\mathcal{B}(B\to K\nu \bar{\nu })$

Abstract

Recently, Belle II reported on the first measurement of $\mathcal{B}(B^{\pm }\to K^{\pm }\nu \bar{\nu })$ which appears to be almost $3\sigma$ larger than predicted in the Standard Model. We point out the important correlation with $\mathcal{B}(B\to K^{\ast }\nu \bar{\nu })$ so that the measurement of that decay mode could help restraining the possible options for building the model of New Physics. We then try to interpret this new experimental result in terms of physics beyond the Standard Model by using SMEFT and find that a scenario with coupling only to $\tau$ can accommodate the current experimental constraints but fails in getting a desired $R_{D^{(\ast )}}^{\exp }/R_{D^{(\ast )}}^{\mathrm{SM}}$, unless one turns the other SMEFT operators that are not related to $b\to s\ell \ell$ or/and $b\to s\nu \nu$.

9 pages, 6 figures. Corrected some typos and improved the discussion

References in corpus (16)

• FLAG Review 2021
• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of 2021
• Two-Loop Electroweak Corrections for the K -> pi nu anti-nu Decays
• $SU(2)\times U(1)$ gauge invariance and the shape of new physics in rare $B$ decays
• Leptoquark model to explain the $B$-physics anomalies, $R_K$ and $R_D$
• On the single leptoquark solutions to the $B$-physics anomalies
• Measurement of the $B_s^0\to {\mu }^{+}{\mu }^{-}$ decay properties and search for the $B^0\to {\mu }^{+}{\mu }^{-}$ and $B_s^0\to {\mu }^{+}{\mu }^{-}\gamma$ decays
• Revisiting $B\to K^{(\ast )}\nu \bar{\nu }$ decays in the Standard Model and beyond
• Semileptonic form factors for $B\to D^{\ast }\ell \nu$ at nonzero recoil from 2 + 1-flavor lattice QCD
• Measurement of the phase difference between short- and long-distance amplitudes in the $B^{+}\to K^{+}{\mu }^{+}{\mu }^{-}$ decay
• Vector Leptoquarks Beyond Tree Level
• HighPT: A Tool for high-$p_T$ Drell-Yan Tails Beyond the Standard Model
• Search for $B^{+}\to K^{+}\nu \bar{\nu }$ decays using an inclusive tagging method at Belle II
• Tree-level contributions to the rare decays B+ --> pi+ nu anti-nu, B+ --> K+ nu anti-nu, and B+ --> K*+ nu anti-nu in the Standard Model
• Vector Leptoquarks Beyond Tree Level II: $\mathcal{O}({\alpha }_s)$ Corrections and Radial Modes
• Consequences of $b\to s{\mu }^{+}{\mu }^{-}$ anomalies on $B\to K^{(\ast )}\nu \bar{\nu }$, $B_s\to (\eta ,{\eta }^{\prime })\nu \bar{\nu }$ and $B_s\to \varphi \nu \bar{\nu }$ decay observables

Cited by in corpus (18)

• Decoding the $B\to K\nu \nu$ excess at Belle II: kinematics, operators, and masses
• $B\to K\nu \bar{\nu }$, MiniBooNE and muon $g-2$ anomalies from a dark sector
• Disentangling left and right-handed neutrino effects in $B\to K^{(\ast )}\nu \nu$
• Correlating $B\to K^{(\ast )}\nu \bar{\nu }$ and flavor anomalies in SMEFT
• The decay $B\to K+\nu +\bar{\nu }$ at Belle II and a massless bino in R-parity-violating supersymmetry
• Impact of new invisible particles on $B\to K^{(\ast )}{E}_{\mathrm{miss}}$ observables
• Searching for signatures of new physics in $B\to K\nu \overline{\nu }$ to distinguish between Dirac and Majorana neutrinos
• Right-handed interactions in puzzling $B$-decays
• Analysis of $q_{\mathrm{rec}}^2$-distribution for $B\to K{M}_X$ and $B\to K^{\ast }{M}_X$ decays in a scalar-mediator dark-matter scenario
• From the EFT to the UV: the complete SMEFT one-loop dictionary
• Resonant ALP-Portal Dark Matter Annihilation as a Solution to the $B^{\pm }\to K^{\pm }\nu \bar{\nu }$ Excess
• Scrutinizing dark-matter scenarios with $B\to (K,K^{\ast })\bar{\nu }\nu$ decays
• Search for $B^0\to K^{\ast 0}{\tau }^{+}{\tau }^{-}$ decays at the Belle II experiment
• Probing vector- vs scalar-mediator dark-matter scenarios in $B\to (K,K^{\ast })M_X$ decays
• Analysis of $B\to K{M}_X$ and $B\to K^{\ast }{M}_X$ decays in scalar- and vector-mediator dark-matter scenarios
• Belle II Constraints on the Non-Minimal Universal Extra Dimensional Model
• Dark Matter emission at Belle II and NA62 in Minimal Flavor Violation framework
• Search for the decay $B^{+}\to K^{+}{\tau }^{+}{\tau }^{-}$ using data from the Belle and Belle II experiments