Neutral kaon mixing beyond the Standard Model with nf = 2 + 1 chiral fermions. Part 2: non perturbative renormalisation of the ΔF = 2 four-quark operators

• Published in: The journal of high energy physics Vol. 2017; no. 10
• Main Authors: Boyle, Peter A., Garron, Nicolas, Hudspith, Renwick J., Lehner, Christoph, Lytle, Andrew T.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 10.10.2017; Springer Berlin
• Subjects: BSM; chiral; Classical and Quantum Gravitation; DM; Elementary Particles; fermions; flavour; kaon; Lattice field theory simulation; Non-perturbative renormalization; particles; Physics; Physics and Astronomy; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Quantum Field Theories; Quantum Field Theory; Quantum Physics; quark; Regular Article - Theoretical Physics; Relativity Theory; RI-SMOM; String Theory; z-matrice; Lattice field theory simulation; Non-perturbative renormalization
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP10(2017)054

A bstract We compute the renormalisation factors ( Z -matrices) of the Δ F = 2 four-quark operators needed for Beyond the Standard Model (BSM) kaon mixing. We work with n f = 2+1 flavours of Domain-Wall fermions whose chiral-flavour properties are essential to maintain a continuum-like mixing pattern. We introduce new RI-SMOM renormalisation schemes, which we argue are better behaved compared to the commonly-used corresponding RI-MOM one. We find that, once converted to M S ¯ , the Z-factors computed through these RI-SMOM schemes are in good agreement but differ significantly from the ones computed through the RI-MOM scheme. The RI-SMOM Z -factors presented here have been used to compute the BSM neutral kaon mixing matrix elements in the companion paper [1]. We argue that the renormalisation procedure is responsible for the discrepancies observed by different collaborations, we will investigate and elucidate the origin of these differences throughout this work.