Probing novel TeV physics through precision calculations of scalar and tensor charges of the nucleon

TL;DR

This paper updates calculations of nucleon scalar and tensor charges using lattice QCD, aiming to probe new physics beyond the Standard Model at the TeV scale through precision matrix element determinations.

Contribution

It provides new lattice QCD results for nucleon charges relevant to testing scalar and tensor interactions in neutron beta-decay, including dependence on quark masses and lattice parameters.

Findings

Matrix elements depend on light quark masses and lattice spacing.

Renormalization constants are close to unity for HYP smeared HISQ lattices.

Preliminary estimates of matrix elements' dependence on simulation parameters.

Abstract

We present an update on the calculation of matrix elements of iso-vector scalar, axial and tensor charges between a neutron and a proton state. These matrix elements are needed to probe novel scalar and tensor interactions in neutron beta-decay that can arise in extensions of the Standard Model at the TeV scale. Our calculations are being done using valence clover fermions on dynamical N_f=2+1+1 HISQ configurations generated by the MILC Collaboration. We provide preliminary estimates of the dependence of these matrix elements on the light quark masses, lattice spacing, and the time separation between the source and sink of the nucleons. We also find that the renormalization constants calculated using the RI-sMOM scheme are close to unity for the HYP smeared HISQ lattices.