Non-perturbative renormalisation and improvement of non-singlet tensor currents in $N_\mathrm{f}=3$ QCD

L. Chimirri, P. Fritzsch, J. Heitger, F. Joswig, M. Panero, C. Pena, D. Preti
High Energy Physics - Lattice, High Energy Physics - Lattice (hep-lat)
HU-EP-23/51, IFT-UAM/CSIC-23-102, MS-TP-23-42, YITP-23-109
2023-09-07 16:00:00
Hadronic matrix elements involving tensor currents play an important r\^ole in decays that allow to probe the consistency of the Standard Model via precision lattice QCD calculations. The non-singlet tensor current is a scale-dependent (anomalous) quantity. We fully resolve its renormalisation group (RG) running in the continuum by carrying out a recursive finite-size scaling technique. In this way ambiguities due to a perturbative RG running and matching to lattice data at low energies are eliminated. We provide the total renormalisation factor at a hadronic scale of 233 MeV, which converts the bare current into its RG-invariant form. Our calculation features three flavours of O(a) improved Wilson fermions and tree-level Symanzik-improved gauge action. We employ the (massless) Schr\"odinger functional renormalisation scheme throughout and present the first non-perturbative determination of the Symanzik counterterm $c_\mathrm{T}$ derived from an axial Ward identity. We elaborate on various details of our calculations, including two different renormalisation conditions.
PDF: Non-perturbative renormalisation and improvement of non-singlet tensor currents in $N_\mathrm{f}=3$ QCD.pdf
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