English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

An analysis is given of the Belle II sensitivities and NA64 constraints onthe sub-GeV Dirac dark matter that interacts with charged leptons. We considertwo different types of interactions between sub-GeV Dirac dark matter and thecharged leptons: the EFT operators and the light vector mediators. We computethe Belle II mono-photon sensitivities on sub-GeV dark matter with 50 ab$^{-1}$data which are expected to be accumulated in the full Belle II runs. Althoughthe Belle II mono-photon sensitivities on the EFT operators are of similar sizeas the LEP constraints, Belle II can probe new parameter space of the lightvector mediator models that are unexplored by LEP. For both the EFT operatorsand the light vector mediator models, the Belle II mono-photon sensitivitiescan be several orders of magnitude stronger than the current dark matter directdetection limits, as well as the white dwarf limits. The light vector mediatorcan also be directly searched for by reconstructing the invariant mass of itsdi-lepton decay final states at Belle II, which is found to be complementary tothe mono-photon channel. We compute the NA64 constraints on the sub-GeV Diracdark matter and provide analytic expressions of the dark matter cross sectionin the Weizs\"acker-Williams approximation, for the EFT operators, and for thelight vector mediator models. We find that the current NA64 data (with $2.84\times 10^{11}$ electron-on-target events) provide strong constraints onsub-GeV dark matter. Although the NA64 constraints are found to be about oneorder of magnitude smaller than the Belle II sensitivities for the EFToperators, NA64 can probe some regions of the parameter space in the lightvector mediator models that are beyond the reach of Belle II.

Probing sub-GeV leptophilic dark matter at Belle II and NA64