# Progress On Neutrino-Proton Neutral-Current Scattering In MicroBooNE

## TL;DR

This paper discusses the MicroBooNE experiment's progress in detecting low-$Q^2$ neutral-current neutrino-proton scattering events to measure the strange quark contribution to the proton spin, using a liquid argon TPC at Fermilab.

## Contribution

It reports on the status of observing isolated proton tracks as signatures of neutrino-proton interactions and evaluates MicroBooNE's sensitivity to the strange quark contribution to proton spin.

## Key findings

- Detection of isolated proton tracks underway
- Assessment of experiment's sensitivity to strange quark contribution
- Progress in measuring low-$Q^2$ neutral-current scattering

## Abstract

The MicroBooNE Experiment at the Fermi National Accelerator Laboratory, an 89-ton active mass liquid argon time projection chamber, affords a unique opportunity to observe low-$Q^2$ neutral-current neutrino-proton scattering events. Neutral-current neutrino-proton scattering at $Q^2 < 1$ GeV$^2$ is dominated by the proton's axial form factor, which can be written as a combination of contributions from the up, down, and strange quarks: $G_A(Q^2) = \frac{1}{2}[-G_A^u(Q^2)+G_A^d(Q^2)+G_A^s(Q^2)]$. The contribution from up and down quarks has been established in past charged-current measurements. The contribution from strange quarks at low $Q^2$ remains unmeasured; this is of great interest since the strange quark contribution to the proton spin can be determined from the low-$Q^2$ behavior: $\Delta S = G_A^s(Q^2=0)$. MicroBooNE began operating in the Booster Neutrino Beam in October 2015. I will present the status in observing isolated proton tracks in the MicroBooNE detector as a signature for neutral-current neutrino-proton events. The sensitivity of the MicroBooNE experiment for measuring the strange quark contribution to the proton spin will be discussed.