Abstract
A vector portal between the Standard Model and the dark sector is a predictive and compelling framework for thermal dark matter. Through co-annihilations, models of inelastic dark matter (iDM) and inelastic Dirac dark matter (i2DM) can reproduce the observed relic density in the MeV to GeV mass range without violating cosmological limits. In these scenarios, the vector mediator behaves like a semi-visible particle, evading traditional bounds on visible or invisible resonances, and uncovering new parameter space to explain the muon (g- 2) anomaly. By means of a more inclusive signal definition at the NA64 experiment, we place new constraints on iDM and i2DM using a missing energy technique. With a recast-based analysis, we contextualize the NA64 exclusion limits in parameter space and estimate the reach of the newly collected and expected future NA64 data. Our results motivate the development of an optimized search program for semi-visible particles, in which fixed-target experiments like NA64 provide a powerful probe in the sub-GeV mass range. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000613335Publication status
publishedExternal links
Journal / series
The European Physical Journal CVolume
Pages / Article No.
Publisher
SpringerOrganisational unit
08718 - Crivelli, Paolo (Tit.-Prof.)
Funding
169133 - NA64 - Search for Dark Sectors in Missing Energy Events (SNF)
186181 - NA64 - Searching for Dark Sectors at the CERN SPS (SNF)
186158 - Development of Data Acquisition Systems based on Silicon Photomultipliers readouts to search for dark sectors in NA64 at CERN (SNF)
197346 - Study of Exotic Matter (SNF)
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