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Benjamin Banto Oberhauser

Publications and source records attributed to Benjamin Banto Oberhauser.

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Feasibility of Low-Energy True Muonium Photoproduction

True muonium, the bound state of a muon and an antimuon, is a theoretically well-understood but experimentally unobserved exotic atom. Its purely leptonic nature makes it a sensitive probe for bound-state quantum electrodynamics and possible physics beyond the Standard Model. We present a feasibility study of low-energy true muonium production via near-threshold photoproduction on a fixed target. The study includes simulations of the signal and dominant background processes, estimates of the required photon fluxes, and an overview of possible gamma sources. We show that the proposed Gamma Factory at CERN could provide the necessary photon energies and rates for the production of true muonium. Furthermore, cut-based selections are shown to suppress the background below the expected signal level. Finally, we discuss possible physics opportunities beyond the first observation, including measurements of its lifetime, hyperfine splitting, and Lamb shift.

hep-ex

Constraining Light Thermal Inelastic Dark Matter with NA64

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.

hep-ph