Probing scalar and pseudoscalar new physics using rare kaon decays

2025/12/18 by G. D'Ambrosio, A. M. Iyer, D'Ambrosio, G. +5
Computer Science · Physics and Astronomy · #Computational Physics and Python Applications #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions

paper · doi:10.48550/arxiv.2512.16903

openalex publication_date 2025/12/18 · openalex created_date 2025/12/21 · openalex updated_date 2026/07/28

Abstract

Rare kaon decays provide sensitive tests of new physics. In this work, we focus on scalar and pseudoscalar operators, analysing the K→ πℓ⁺ℓ^- and K→ ℓ⁺ℓ^- decays. We highlight the complementary role of different modes: K⁺→π⁺ℓ⁺ℓ^-, in particular the forward-backward asymmetry in the muon channel as a clean probe of scalar effects, the stringent constraints from K_L→ μ⁺μ^-, and the discovery potential of future measurements of K_S→ μ⁺μ^- and K_L→ π⁰ ℓ⁺ℓ^-. The interplay between charged and neutral modes underscores the complementarity of NA62, the LHCb upgrade, and KOTO-II.

Citations

• Physics Briefing Book: Input for the 2026 update of the European Strategy for Particle Physics
• Experimental Study of Rare Kaon Decays at J-PARC with KOTO and KOTO II
• Kaon Physics: A Cornerstone for Future Discoveries
• Proposal of the KOTO II experiment
• High Intensity Kaon Experiments (HIKE) at the CERN SPS Proposal for Phases 1 and 2
• Flavour Physics with SuperIso
• Fundamental Composite Dynamics: A Review
• Theory and phenomenology of two-Higgs-doublet models
• Search for the decay K_S->e+e-

Related

• Rare strange particle decays
• Rare Kaon Decays
• Rare decays at the CERN high-intensity kaon beam facility
• Rare Kaon decays
• Prospects for K_L→π⁰νν, K_S→μ⁺μ^-, K_L→π⁰ ℓ⁺ℓ^- and ε^′/ε after the new K⁺→π⁺νν result from NA62