2014/12/31 by Kaori Fuyuto, W.-S. Hou, Wei-Shu Hou +1 · 54 citations
Physics and Astronomy · #Black Holes and Theoretical Physics #Electron #Geometry #Large Hadron Collider #Lepton #Muon #Nuclear physics #Particle physics #Particle physics theoretical and experimental studies #Physics #Physics beyond the Standard Model #Quantum Chromodynamics and Particle Interactions #Scalar (mathematics) #hep-ph
paper · pdf · doi:10.1103/physrevlett.114.171802
published in Physical Review Letters 114(17), 171802 (American Physical Society) · 5 pages, 3 figures, title changed, version to appear in PRL
arxiv created 2015/04/26 · openalex publication_date 2015/04/29 · arxiv updated 2015/05/06 · openalex created_date 2016/11/30 · openalex updated_date 2026/08/05
Weakly interacting K\ensuremath→\ensuremathπX0 emission with m_X0\ensuremath≅m_\ensuremathπ0 is out of sight of the current K+\ensuremath→\ensuremathπ+\ensuremathν\ensuremathν study, but it can be sensed by the KL\ensuremath→\ensuremathπ0\ensuremathν\ensuremathν search. This evades the usual Grossman-Nir bound of B(KL\ensuremath→\ensuremathπ0\ensuremathν\ensuremathν)<1.4\ifmmode×\else\texttimes\fi10^\ensuremath-9; thus, the KOTO experiment is already starting to probe new physics. An intriguing possibility is the Z^\ensuremath' gauge boson of a weak leptonic force that couples to L_\ensuremathμ\ensuremath-L_\ensuremathτ (the difference between the muon and tauon numbers), which may explain the long-standing ``muon g\ensuremath-2'' anomaly, but is constrained by \ensuremathν_\ensuremathμN\ensuremath→\ensuremathν_\ensuremathμN\ensuremathμ+\ensuremathμ^\ensuremath- scattering to m_Z^\ensuremath'\ensuremath\lesssim400 MeV. An explicit model for K\ensuremath→\ensuremathπZ^\ensuremath' is given, which illustrates the link between rare kaon and B\ensuremath→K\ensuremathμ+\ensuremathμ^\ensuremath-, K(*)\ensuremathν\ensuremathν decays. Complementary to these searches and future lepton experiments, the LHC might discover the scalar boson \ensuremathφ responsible for light m_Z^\ensuremath' generation via \ensuremathφ\ensuremath→Z^\ensuremath'Z^\ensuremath'\ensuremath→2(\ensuremathμ+\ensuremathμ^\ensuremath-).