Light Dilaton in Rare Meson Decays and Extraction of its CP Property

Abstract

The dilaton $\varphi$ is a pseudo-Nambu-Goldstone boson associated with the spontaneous breaking of scale invariance in a nearly conformal theory, and couples to the trace of the stress-energy tensor. We analyze experimental constraints on a light dilaton with mass in the MeV-GeV range from rare meson decays. New model-independent inclusive bounds for the $b\to s\varphi$ transition largely exclude the parameter space of a light dilaton that could explain the muon $g-2$ anomaly. Despite similarities between a dilaton and a Higgs-portal scalar, the dilaton-photon coupling is enhanced compared to the Higgs-portal scalar due to contributions from loops of the conformal sector. Consequently, the shortened lifetime of the dilaton relaxes bounds from $K\to \pi$ + invisible searches at the NA62 experiment and constraints from the Big Bang Nucleosynthesis. We utilize this fact to search for the dilaton signature at a lepton collider such as the ongoing Belle II experiment. Further, we demonstrate how to extract the CP property of the dilaton using the variation of the differential cross-section of $e^{+}{e}^{-}\to e^{+}{e}^{-}\varphi$ with the azimuthal angle between the outgoing leptons.

arXiv comment14 pages, 5 figures

References in corpus (35)

• Gauge Theory Correlators from Non-Critical String Theory
• A Large Mass Hierarchy from a Small Extra Dimension
• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• Modulus Stabilization with Bulk Fields
• The anomalous magnetic moment of the muon in the Standard Model
• New Results on B->pi, K, eta Decay Formfactors from Light-Cone Sum Rules
• The muon $g-2$ and $\alpha (M_Z^2)$: a new data-based analysis
• Holography and Phenomenology
• Comments on the Holographic Picture of the Randall-Sundrum Model
• Radion Dynamics and Electroweak Physics
• Light scalar at LHC: the Higgs or the dilaton?
• Determining the Structure of Higgs Couplings at the LHC
• Revised constraints and Belle II sensitivity for visible and invisible axion-like particles
• Probing Light Thermal Dark-Matter With a Higgs Portal Mediator
• Flavor probes of axion-like particles
• Decay and Detection of a Light Scalar Boson Mixing with the Higgs
• Contributions of axion-like particles to lepton dipole moments
• A Higgslike Dilaton
• Coupling QCD-scale axion-like particles to gluons
• Radion Phenomenology in Realistic Warped Space Models
• Multi-lepton Signatures of a Hidden Sector in Rare B Decays
• Effective Theory of a Light Dilaton
• A Naturally Light Dilaton and a Small Cosmological Constant
• BBN for the LHC: constraints on lifetimes of the Higgs portal scalars
• A naturally light dilaton
• Constraining the Axion Portal with B -> K l+ l-
• Higgs Decay to Two Photons
• Implications of a Light "Dark Higgs" Solution to the $g_{\mu }-2$ Discrepancy
• A more attractive scheme for radion stabilization and supercooled phase transition
• Crunching Dilaton, Hidden Naturalness
• Higgs portal to dark matter and $B\to K^{(\ast )}$ decays
• Search for muon-philic new light gauge boson at Belle II
• The Light Radion Window
• Upper limits on branching ratios of the lepton-flavor-violating decays $\tau \to \ell \gamma \gamma$ and $\tau \to \ell X$
• Muon anomalous magnetic moment and penguin loops in warped extra dimensions

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• A comprehensive study of ALPs from $B$-decays
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