f_K/f_π in iso-symmetric QCD and the CKM matrix unitarity

2025/12/22 by Alessandro Conigli, Conigli, Alessandro, Julien Frison +3
Physics and Astronomy · #Quantum Chromodynamics and Particle Interactions #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies

paper · doi:10.48550/arxiv.2512.19294

Abstract

We present lattice results for f_K/f_π in the iso-symmetric limit of pure QCD (isoQCD) with N_f=2+1 flavours, along with a determination of |V_us|/|V_ud| and a study on the unitarity of the first row of the Cabibbo-Kobayashi-Maskawa (CKM) matrix after introducing strong isospin-breaking and QED effects. The results obtained are based on a combination of a Wilson unitary action and the mixed-action setup introduced in arXiv:2309.14154, arXiv:2510.20450. The combination of the two regularisations enables a more precise control over the continuum-limit extrapolation.

Citations

• Hadronic physics from a Wilson fermion mixed-action approach: Setup and scale setting
• Quark masses and low energy constants in the continuum from the tadpole improved clover ensembles
• Hadronic physics from a Wilson fermion mixed-action approach: Charm quark mass and D_(s) meson decay constants
• Low-mode deflation for twisted-mass and RHMC reweighting in lattice QCD
• Towards fully bayesian analyses in Lattice QCD
• Review of lattice results concerning low-energy particle physics
• Experimental determination of V_us from kaon decays
• Results for light pseudoscalar mesons

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