Neutral kaon mixing from new physics: matrix elements in $N_f=2+1$ QCD

Abstract

We present results for matrix elements of $\Delta S=2$ four-fermion operators arising generically in models of new physics. These are needed to constrain such models using the measured values of ${\epsilon }_K$ and $\Delta M_K$. We use lattice QCD with 2+1 flavors of improved staggered fermions on lattices generated by the MILC collaboration. We extrapolate to the continuum from three lattice spacings ranging down to $a\approx 0.045$fm. Total errors are $\sim 5-6$, arising primarily from our use of one-loop matching between lattice and continuum operators. For two of the matrix elements, our results disagree significantly from those obtained using different fermion discretizations.

5 pages, 3 figures, added references

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Cited by in corpus (18)

• FLAG Review 2019
• FLAG Review 2021
• Towards the Identification of New Physics through Quark Flavour Violating Processes
• Present and Future K and B Meson Mixing Constraints on TeV Scale Left-Right Symmetry
• ΔS=2 and ΔC=2 bag parameters in the SM and beyond from Nf=2+1+1 twisted-mass LQCD
• FLAG Review 2024
• Towards grounding nuclear physics in QCD
• Neutral Kaon Mixing Beyond the Standard Model with $n_f=2+1$ Chiral Fermions Part 1: Bare Matrix Elements and Physical Results
• Heavy physics contributions to neutrinoless double beta decay from QCD
• Kaon BSM B-parameters using improved staggered fermions from $N_f=2+1$ unquenched QCD
• Lattice QCD Inputs for Nuclear Double Beta Decay
• Neutral Kaon mixing beyond the Standard Model
• Flavor from the Electroweak Scale
• Toolkit for staggered $\Delta S=2$ matrix elements
• Beyond the Standard Model B-parameters with improved staggered fermions in $N_f=2+1$ QCD
• Masses and decay constants of pions and kaons in mixed-action staggered chiral perturbation theory
• $K$ and $D$ oscillations in the Standard Model and its extensions from $N_f=2+1+1$ Twisted Mass LQCD
• Quark Flavor Physics Review