Weak Neutral Current Axial Form Factor Using $(\bar{\nu })\nu$-Nucleon Scattering and Lattice QCD Inputs

Abstract

We present a determination of the neutral current weak axial charge $G_A^Z(0)=-0.654(3{)}_{\mathrm{stat}}(5{)}_{\mathrm{sys}}$ using the strange quark axial charge $G_A^s(0)$ calculated with lattice QCD. We then perform a phenomenological analysis, where we combine the strange quark electromagnetic form factor from lattice QCD with (anti)neutrino-nucleon scattering differential cross section from MiniBooNE experiments in a momentum transfer region $0.24\lesssim Q^2\lesssim 0.71$ GeV${}^2$ to determine the neutral current weak axial form factor $G_A^Z(Q^2)$ in the range of $0\lesssim Q^2\le 1$ GeV${}^2$. This yields a phenomenological value of $G_A^Z(0)=-0.687(89{)}_{\mathrm{stat}}(40{)}_{\mathrm{sys}}$. The value of $G_A^Z(0)$ constrained by the lattice QCD calculation of $G_A^s(0)$, when compared to its phenomenological determination, provides a significant improvement in precision and accuracy and can be used to provide a constraint on the fit to $G_A^Z(Q^2)$ for $Q^2>0$. This constrained fit leads to an unambiguous determination of (anti)neutrino-nucleon neutral current elastic scattering differential cross section near $Q^2=0$ and can play an important role in numerically isolating nuclear effects in this region. We show a consistent description of $G_A^Z(Q^2)$ obtained from the (anti)neutrino-nucleon scattering cross section data requires a nonzero contribution of the strange quark electromagnetic form factor. We demonstrate the robustness of our analysis by providing a post-diction of the BNL E734 experimental data.

Published Version (20 pages, 4 figures)

References in corpus (17)

• Extraction of Spin-Dependent Parton Densities and Their Uncertainties
• A first unbiased global determination of polarized PDFs and their uncertainties
• Status of non-standard neutrino interactions
• First simultaneous extraction of spin-dependent parton distributions and fragmentation functions from a global QCD analysis
• A percent-level determination of the nucleon axial coupling from Quantum Chromodynamics
• Precision Measurement of the Weak Charge of the Proton
• QCD Analysis of the Polarized World Data
• Proton and neutron electromagnetic form factors and uncertainties
• Progress and open questions in the physics of neutrino cross sections
• Quark spins and Anomalous Ward Identity
• Model independent extraction of the proton magnetic radius from electron scattering
• Determination of gluon polarization from deep inelastic scattering and collider data
• Parity-Violating Electron Scattering and the Electric and Magnetic Strange Form Factors of the Nucleon
• Lattice QCD and Neutrino-Nucleus Scattering
• New analysis concerning the strange quark polarization puzzle
• A Possible Resolution of the Strange Quark Polarization Puzzle ?
• Strange electromagnetic form factors of the nucleon with $N_f=2+1$ $\mathcal{O}(a)$-improved Wilson fermions

Cited by in corpus (5)

• Theoretical tools for neutrino scattering: interplay between lattice QCD, EFTs, nuclear physics, phenomenology, and neutrino event generators
• Relativistic energy-momentum tensor distributions in a polarized nucleon
• Axial transition form factors of octet baryons in the perturbative chiral quark model
• Neutral-current neutrino-nucleus scattering off I (127) and Cs (133): Coherent and incoherent contributions with electroweak refinements for odd-A nuclei
• Neutral-Current Neutrino Scattering from the Deuteron