Displaced Searches for Light Vector Bosons at Belle II

Abstract

With a design luminosity of 50 ab${}^{-1}$ and detectors with tracking capabilities extending beyond 1 m, the Belle II experiment is the perfect laboratory for the search of particles that couple weakly to the Standard Model and have a characteristic decay length of a few centimetres and more. We show that for models of dark photons and other light vector bosons, Belle II will be successful in probing regions of parameter space which are as of now unexplored by any experiment. In addition, for models where the vector boson couples sub-dominantly to the electron and quarks as compared to muons, e.g. in the $L_{\mu }-L_{\tau }$ model, Belle II will probe regions of mass and couplings compatible with the anomalous magnetic moment of muon. We discuss these results and derive the projected sensitivity of Belle II for a handful of other models. Finally, even with the currently accumulated data, $\sim 200$ fb${}^{-1}$, Belle II should be able to cover regions of parameter space pertaining to the X(17) boson postulated to solve the ATOMKI anomaly.

Published version. 19 pages, 8 figures. Minor Changes

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Cited by in corpus (10)

• Supernova Limits on Muonic Dark Forces
• Forecasting dark showers at Belle II
• Probing $R$-parity violation in $B$-meson decays to a baryon and a light neutralino
• Displaced Signals of Hidden Vectors at the Electron-Ion Collider
• Searching Dark Photons using displaced vertices at Belle II -- with backgrounds
• A comprehensive study of ALPs from $B$-decays
• Prospects of five-dimensional $L_{\mu }-L_{\tau }$ gauge interactions in the light of elastic neutrino-electron scatterings: The scope of the DUNE near detector
• Systematic analysis of search strategies for $L_{\mu }-L_{\tau }$ gauge bosons at Belle II
• Contributions to $Z^0$ decays from a X17 extension of the Standard Model
• Muon Beam Dump Experiments probe five-dimensional nature of $U(1{)}_{L_{\mu }-L_{\tau }}$