Kaon mixing beyond the standard model with physical masses

2024/04/02 by Peter A. Boyle, Boyle, Peter A., Felix Erben +11 · 3 citations
Biochemistry, Genetics and Molecular Biology · Physics and Astronomy · #Astro and Planetary Science #FOS: Physical sciences #Geomagnetism and Paleomagnetism Studies #High Energy Physics - Lattice (hep-lat) #High Energy Physics - Phenomenology (hep-ph) #Ionosphere and magnetosphere dynamics

paper · pdf · doi:10.48550/arxiv.2404.02297

openalex publication_date 2024/04/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01

Abstract

We present non-perturbative results for beyond the standard model kaon mixing matrix elements in the isospin symmetric limit (m_u=m_d) of QCD, including a complete estimate of all dominant sources of systematic error. Our results are obtained from numerical simulations of lattice QCD with N_f = 2+1 flavours of dynamical domain wall fermions. For the first time, these quantities are simulated directly at the physical pion mass m_π~∼~139 MeV for two different lattice spacings. We include data at three lattice spacings in the range a = 0.11 - 0.07 fm and with pion masses ranging from the physical value up to 450 MeV. Compared to our earlier work, we have added both direct calculations at physical quark masses and a third lattice spacing making the removal of discretisation effects significantly more precise and eliminating the need for any significant mass extrapolation beyond the range of simulated data. We renormalise the lattice operators non-perturbatively using RI-SMOM off-shell schemes. These schemes eliminate the need to model and subtract non-perturbative pion poles that arises in the RI-MOM scheme and, since the calculations are performed with domain wall fermions, the unphysical mixing between chirality sectors is suppressed. Our results for the bag parameters in the MS scheme at 3 GeV are B_K~≡~B₁ = 0.5240(17)(54), B₂ = 0.4794(25)(35), B₃ = 0.746(13)(17), B₄ = 0.897(02)(10) and B₅ = 0.6882(78)(94), where the first error is from lattice uncertainties and the second is the uncertainty due to the perturbative matching to MS.

Cited by

• Application of Laplace filters to the analysis of lattice time correlators
• Lattice Calculation of Short-Range Contributions to Neutrinoless Double-Beta Decay π^-→π⁺ ee at Physical Pion Mass
• The flavour of SU(15) composite quarks and leptons

Related

• Beyond the Standard Model Kaon Mixing with Physical Masses
• Kaon Mixing Beyond the Standard Model
• Neutral Kaon mixing beyond the Standard Model
• BSM Kaon Mixing at the Physical Point
• Precision flavor physics from the lattice