Abstract

Tensor currents are the only quark bilinear operators lacking a non-perturbative determination of their renormalisation group (RG) running between hadronic and electroweak scales. We develop the setup to carry out the computation in lattice QCD via standard recursive finite-size scaling techniques, and provide results for the RG running of tensor currents in N_f=0 and N_f=2 QCD in the continuum for various Schrödinger Functional schemes. The matching factors between bare and renormalisation group invariant currents are also determined for a range of values of the lattice spacing relevant for large-volume simulations, thus enabling a fully non-perturbative renormalization of physical amplitudes mediated by tensor currents.

Highlights

  • Hadronic matrix elements of tensor currents play an important rôle in several relevant problems in particle physics

  • We develop the setup to carry out the computation in lattice QCD via standard recursive finite-size scaling techniques, and provide results for the renormalisation group (RG) running of tensor currents in N f = 0 and N f = 2 QCD in the continuum for various Schrödinger Functional schemes

  • The matching factors between bare and renormalisation group invariant currents are determined for a range of values of the lattice spacing relevant for large-volume simulations, enabling a fully non-perturbative renormalization of physical amplitudes mediated by tensor currents

Read more

Summary

Introduction

Hadronic matrix elements of tensor currents play an important rôle in several relevant problems in particle physics. Some prominent examples are rare heavy meson decays that allow to probe the consistency of the Standard Model (SM) flavour sector (see, e.g., [1,2,3] for an overview), or precision measurements of β-decay and limits on the neutron electric dipole moment (see, e.g., [4,5,6] for an up-to-date lattice-QCD perspective). One of the key ingredients in these computations is the renormalization of the current. Partial current conservation ensures that non-singlet vector and axial currents require at worst finite normalizations, and fixes the anomalous dimension of scalar and pseudoscalar densities to be

Preti: address since December 2017
Renormalization group
Schrödinger Functional renormalization schemes
Perturbative study
Perturbative scheme matching
One-loop cutoff effects in the step scaling function
Non-perturbative computations
Continuum extrapolation of SSFs
Fits to continuum step-scaling functions
Determination of the non-perturbative running factor
Hadronic matching
Non-perturbative running
Conclusions
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call