# New $μ$ Forces From $ν_μ$ Sources

**Authors:** Cari Cesarotti, Yonatan Kahn, Gordan Krnjaic, Duncan Rocha, Joshua Spitz  
**arXiv:** [2311.10829](https://arxiv.org/abs/2311.10829)  
**Date:** 2023-11-17  
**Summary page:** https://www.summarizepaper.com/en/arxiv-id/2311.10829v1/

## Key points

- Accelerator-based experiments are crucial for exploring new particles in particle physics
- Charged pion and kaon decays produce muon-neutrino beams and muons, allowing for detection of light new particles interacting with muons
- Previous studies at MiniBooNE and MicroBooNE established constraints on light muon-philic scalar particles through neutral pion production
- Results ruled out scalars with masses from 10 to 60 MeV, potentially addressing the muon $g-2$ anomaly
- SBND is projected to have sensitivity to these models, paving the way for future neutrino experiments focusing on forces interacting preferentially with muons
- Interest is growing in weakly-coupled particles as extensions of the Standard Model, offering insights into dark matter composition, hierarchy problem, and strong CP problem
- There is increasing emphasis on dedicated muon-beam experiments for studying muons directly and exploring experimental milestones
- By refining search strategies for new particles interacting with muons, researchers are driving towards groundbreaking discoveries in particle physics

## Summary

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In the realm of particle physics, accelerator-based experiments have played a crucial role in exploring new particles that could potentially answer fundamental questions about the universe. One such avenue of exploration involves charged pion and kaon decays, which produce muon-neutrino beams along with a powerful flux of muons. These experiments have the potential to detect light new particles that interact specifically with muons and decay into visible final states over significant distances. These elusive particles are generated through rare 3-body meson decays within the decay pipe or via interactions with muons in the beam dump, eventually decaying in a downstream detector. To showcase the effectiveness of this search strategy, previous studies conducted at MiniBooNE and MicroBooNE focused on neutral pion production in neutrino-induced neutral-current scattering ($\nu_\mu N \to \nu_\mu N \pi^0,~\pi^0\rightarrow \gamma\gamma$). By reanalyzing these studies, researchers were able to establish new leading constraints on light ($< 2m_\mu$) muon-philic scalar particles that decay into diphotons through loops involving virtual muons. The results of these investigations ruled out scalars with masses ranging from 10 to 60 MeV, offering a potential solution to the longstanding muon $g-2$ anomaly. Furthermore, projections were made regarding the sensitivity of SBND (Short-Baseline Neutrino Detector) to these models, laying out a roadmap for future neutrino experiments to conduct dedicated searches for forces that exhibit a preference for interacting with muons. Expanding on this research landscape, there is a growing interest in exploring weakly-coupled particles as extensions of the Standard Model. These particles could provide insights into unresolved mysteries such as dark matter composition, the hierarchy problem, and the strong CP problem. While most current searches focus on proton or electron beams, there has been an increasing emphasis on dedicated muon-beam experiments due to unexplored experimental milestones related to studying muons directly. In conclusion, by delving deeper into accelerator-based experiments and refining search strategies for new particles that interact with muons, researchers are paving the way for groundbreaking discoveries that could reshape our understanding of particle physics and address some of its most pressing questions.