Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 2312.12507

Decoding the $B \to K νν$ excess at Belle II: kinematics, operators, and masses

Kåre Fridell·Mitrajyoti Ghosh·Takemichi Okui·Kohsaku Tobioka
View original source ↗Read source document ↗Export metadata ↓

Abstract

An excess in the branching fraction for $B^+ \to K^+ νν$ recently measured at Belle II may be a hint of new physics. We perform thorough likelihood analyses for different new physics scenarios such as $B \to KX$ with a new invisible particle $X$, or $B\to Kχχ$ through a scalar, vector, or tensor current with $χ$ being a new invisible particle or a neutrino. We find that vector-current 3-body decay with $m_X \simeq 0.6$ GeV - which may be dark matter - is most favored, while 2-body decay with $m_X \simeq 2$ GeV is also competitive. The best-fit branching fractions for the scalar and tensor cases are a few times larger than for the 2-body and vector cases. Past BaBar measurements provide further discrimination, although the best-fit parameters stay similar.

Explore related subjects

hep-phhep-ex

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Kåre Fridell, Mitrajyoti Ghosh, Takemichi Okui, Kohsaku Tobioka. 2024-07-10. Decoding the $B \to K νν$ excess at Belle II: kinematics, operators, and masses. https://doi.org/10.1103/physrevd.109.115006

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Exploring the Singlino-dominated Thermal Neutralino Dark Matter in the $Z_3$ invariant NMSSM

We examine the parameter space of the Next to Minimal Supersymmetric Standard Model (NMSSM) with Singlino-dominated neutralino $\widetildeχ_1^0$ as the lightest supersymmetric particle (LSP). Our study focuses on identifying the regions within this parameter space that produce a thermal relic abundance of $\widetildeχ_1^0$ smaller than the observed cold dark matter relic density while remaining consistent with constraints from LEP measurements, low-energy experiments, Higgs measurements, LHC data, and dark matter direct detection experiments. We identify the dominant annihilation modes of the LSP neutralino across varying LSP mass ranges $\sim \mathcal{O}(1)-\mathcal{O}(10^{3})~$GeV. Furthermore, we conduct a benchmark study to assess the production rates of triple-boson final states emerging from direct electroweakino pair production at the LHC. Drawing insights from these findings, we perform a detailed collider analysis to explore the future potential of probing the triple-boson final states involving a light Higgs boson at the high-luminosity LHC (HL-LHC).

hep-ph↗
arXiv2026

A Finite-History Interpretation of the AMS-02 Positron Spectrum

I examine whether the separation between the characteristic energy scales of cosmic-ray electrons and positrons can be understood as a finite-history effect, without introducing a separate dominant source specifically to generate the high-energy positron feature. In this description the positron retains the opposite Dirac phase orientation relative to ordinary matter clocks, while local interactions and positive physical energies remain unchanged. Reduced accumulated overlap with the matter-defined Galactic environment is represented by a single, approximately shape-preserving energy rescaling. An illustrative overlap benchmark moves the broad structure of an empirical electron reference near 10 GeV into the few-hundred-GeV region. A number-conserving spatial-dilution example provides an order-of-magnitude interpretation of the relative amplitude. The comparison uses the published AMS-02 electron spectrum directly, with fixed, rounded horizontal and vertical scales rather than optimized spectral parameters. Known populations, including pulsars, may contribute subleading components in this interpretation. The resulting characteristic-scale displacement and geometrical amplitude interpretation provide a possible physical account of the positron spectral hierarchy.

hep-ph↗
arXiv2026

A Common Antimatter Response in AMS-02 Positrons and Antiprotons

I present a common finite-history picture for the contrasting spectra of cosmic-ray positrons and antiprotons. Particles and antiparticles retain opposite Dirac phase orientations relative to ordinary matter clocks, while local interactions and positive physical energies remain unchanged. The finite-history description assigns their accumulated response a different overlap with the matter-defined Galactic environment. Its leading effect is represented by a single, approximately shape-preserving rescaling. For positrons, an illustrative overlap benchmark moves the broad structure of an empirical electron reference near 10 GeV into the few-hundred-GeV region, without introducing a separate dominant source specifically to generate that feature. A number-conserving spatial-dilution example provides an order-of-magnitude interpretation of the relative amplitude. For antiprotons, ordinary secondary production supplies an approximately power-law reference; a scale-neutral response preserves its index and gives a nearly constant antiproton-to-proton ratio. Direct comparisons with the published AMS-02 spectra illustrate these two outcomes using fixed, rounded scales. The resulting characteristic-scale displacement and spectral-index preservation provide a unified physical organization of two otherwise different antimatter observations.

hep-ph↗