arXiv subjects

Joachim Weiss

Publications and source records attributed to Joachim Weiss.

2 recordsLinked to original sources

arXiv2024

A Leptonic ALP Portal to the Dark Sector

We discuss the leptonic ALP portal as a simple scenario that connects observed discrepancies in anomalous magnetic moments to the Dark Matter relic abundance. In this framework an axion-like particle in the multi-MeV range couples to SM leptons and a DM fermion, with mass above the ALP mass but below a GeV. The ALP contributes to $(g-2)_μ$ and $(g-2)_e$ dominantly through 2-loop Barr-Zee diagrams, while the DM abundance is generated by $p$-wave annihilation to ALP pairs. Constraints from beam-dump experiments, colliders and CMB probes are very stringent, and restrict the viable parameter space to a rather narrow region that will be tested in the near future.

hep-ph↗

arXiv2024

LHC tau-pair production constraints on $a_τ$ and $d_τ$

We point out that relevant constraints on the anomalous magnetic ($a_τ$) and electric ($d_τ$) moment of the tau lepton can be derived from tau-pair production measurements performed at the LHC. Our conclusion is based on the observation that the leading relative deviations from the Standard Model prediction for $pp \to τ^+ τ^-$ due to $a_τ$ and $d_τ$ are enhanced at high energies. Less precise measurements at hadron colliders can therefore offer the same or better sensitivity to new physics with respect to high-precision low-energy measurements performed at lepton machines. We derive bounds on $a_τ$ and $d_τ$ using the full LHC Run II data set on tau-pair production and compare our findings with the current best limits on the tau anomalous moments.

hep-ph↗