Measurement of the Neutrino Neutral-Current Elastic Differential Cross Section

TL;DR

This paper measures the neutrino neutral-current elastic differential cross section on mineral oil, fitting nucleon form factors to determine an axial mass and estimating the strange quark contribution to the nucleon spin.

Contribution

It provides the first measurement of the differential cross section as a function of four-momentum transfer and constrains the strange quark contribution to the nucleon spin.

Findings

Best-fit axial mass M_A=1.39±0.11 GeV

Strange quark contribution Δs=0.08±0.26

Differential cross section data supports nucleon form factor models

Abstract

We report a measurement of the flux-averaged neutral-current elastic differential cross section for neutrinos scattering on mineral oil (CH$_2$) as a function of four-momentum transferred squared. It is obtained by measuring the kinematics of recoiling nucleons with kinetic energy greater than 50~MeV which are readily detected in MiniBooNE. This differential cross-section distribution is fit with fixed nucleon form factors apart from an axial mass, $M_{A}$, that provides a best fit for $M_A= 1.39\pm0.11$~GeV. Additionally, single protons with kinetic energies above 350 MeV can be distinguished from neutrons and multiple nucleon events. Using this marker, the strange quark contribution to the neutral-current axial vector form factor at $Q^2 = 0$, $\Delta s$, is found to be $\Delta s=0.08\pm0.26$.